Capillary electrophoresis (applications)
28
Hadamard-transform spectroscopy
40
Optical
46
spectrometry
Chromatography
56
Capillary electrophoresis (Instruments)
58
Mass
59
spectrometry
Thermal analysis
March 18, 1991 C&EN
Crisis...
63
Rapid change has been a constant companion of the analytical community. Mostly that change has been driven by the relentless evolution of existing analytical techniques, occasionally punctuated by the appearance of new ones. That process continues. Recent years, however, have seen influential changes taking place as well in the business and laboratory environments in which the instruments are marketed and used. For 20
t Laboratory
instrument manufacturers, the business environment has been affected by the pressures of shifting markets, such as the growth of environmental and biomedical, and the development of new business areas, such as customer service. There are pressures developing as well out of the global nature of the business—most recently the prospects for firms that will be facing a unified European market at the end of 1992. For practitioners and laboratory
managers, the lab environment is also changing. It is being affected by t h e t e c h n o l o g y of n e t w o r k i n g , which is propelling communications and information handling to new levels of sophistication. Such are the forces at work on the analytical community. Over the years, the Pittsburgh Conference & Exposition on Analytical Chemistry & Applied Spectroscopy has been an occasion for their manifestation. The just-ended 1991 conference and ex-
New Text Pittsburgh Conference makes stop in Chicago
| _
_ WSUfggF^
^s^gl^gm
position is no exception, furnishing various images of ongoing change. One example of ongoing change relating to markets comes from the experience of mass spectrometer manufacturer Finnigan MAT. At a press briefing, Finnigan MAT presi dent Τ. Ζ. Chu noted that in 1990, the company's worldwide market was split into biomedical, 26%; envi ronmental, 25%; industrial analyti cal, 23%; research and education, 14%; and food, energy, and natural
111'
As is customary for the Pittsburgh Conference & Exposition on Analytical Chemistry & Applied Spectroscopy, it was an other big production early this month, when the 42nd edition went on the boards at Chicago's McCormick Place. It marked the conclusion of the conference and exposition's most recent northern sojourn, as the organizers set sights on New Orleans. The Crescent City will play host to the 43rd outing next March. But it was quite a show in the Windy City. With more than 950 exhibitors and technical programs occupying more than half a million square feet of area, this year's Pittsburgh Conference was the largest in the organization's history. Conference organizers hoped to leave a lasting mark on Chicago. Designating March 4 - 8 as Science Week, confer ence officials worked with Chicago-area business leaders, the Board of Education, local members of the American Chemical Society, and the Museum of Science & Industry to demonstrate to high school science students how scientific principles are at work around them. Some 1500 students and more than 60 teachers attended the conference as guests during the week, viewing exhibits and hearing ac companying lecture-demonstrations. Altogether, science education benefits from the Pitts burgh Conference total more than $500,000 annually. Among the programs sponsored by the conference are col lege grants and scholarships to high school seniors, awards to high school teachers for outstanding performance, starter grants for young professors, library subscriptions, science center endowments, and distinctive philanthropic projects at a national level. Originating 42 years ago in Pittsburgh, the conference has long since outgrown the facilities of many of the cities it has stopped in during that time. But it is still organized by volunteers from the Spectroscopy Society of Pittsburgh and the Society for Analytical Chemists of Pittsburgh. In the following articles, C&EN editors James Krieger, Stephen Stinson, Ward Worthy, and Ron Dagani survey this year's conference for a current view of business, research, and products in the analytical marketplace.
resources, 12%. It was the first year that biomedical surpassed environ mental, which five years ago was about 40%. But the changes are more complex than just shifts in percentages. The specific nature of the markets is changing very rapidly, Chu points out. For example, he says, a year or two ago, the majority of the envi ronmental market would have im plied an Environmental Protection Agency contract laboratory program
type of user. Today, there is more rapid growth in dioxin analysis with high-resolution mass spectrometry, herbicides analysis with liquid chro matography/mass spectrometry, and a greater emphasis on trace-level pesticide analysis for food a n d drinking water with ion trap MS. Also, Chu says, there is a gradual shift in importance from primarily EPA-mandated methods to a larger role being played by the Food & Drug Administration. March 18, 1991 C&EN
21
A different dimension of change is being brought to the business environment by growth in the customer service sector. An example of the effect this has had is provided by Hewlett-Packard. Dieter Hoehn, vice president and general manager of Hewlett-Packard's analytical products group, noted at a press briefing in Chicago that customer In one way or another, networking was a theme running throughout the exhibits of a variety of instrument, computer, and software companies. Among those making a point of networking (clockwise from below): Sun Microsystems, Molecular Design Ltd., Beckman, Varian, Hewlett-Packard, and IBM (
I R - I H - V T W
r
t o r 1 . i h o r . i h >r\ •
22
March 18, 1991 C&EN
Vlw conn
< . : : 1 ? | > 1111'
' uT
\u!> >!•;•;• •
support has evolved into a major competitive differentiator in the industry. "For HP Analytical/' he says, "customer service has passed the $100 million level and requires an increasing portion of our assets, people, and dollars." Customer service has come a long way from its roots in a service department that was mainly devoted to hardware maintenance, notes Charles G. Walker III, customer support manager of HP's analytical products group. Its growth and change are being driven by a number of factors, Walker says. Among them: pressure from the global economy to maximize return from equipment investment, the need to automate laboratories and to train people to make up for the shortage of skilled labor, and the growing sophistication of measurement and computation solutions. Collectively, Walker says, these factors are reshaping a customer support environment that presents tremendous business opportunities, but daunting challenges as well. "The successful customer support organization in the '90s," he says, "will require, in addition to excellent people and leading-edge technology, a real commitment to managing it as a business." There is another change sweeping through the analytical community, however, affecting manufacturer and user alike. By whatever name the concept is called—integrated laboratory, unified laboratory, synergy—networking is an area atumble with activity. The concept has been gaining ground for several years, but now embodiments of it are emerging rapidly. Across the board, instrument manufacturers have embraced the concept, computer and workstation manufacturers are promoting it, and applications software developers are applying their efforts to it. The concept is one of communication. Large laboratories have many different types of instrumentation made by many different manufacturers. They produce data at very different rates and in vastly different amounts. And they operate with a wide variety of computer systems, from PCs to workstations to minicomputers to centralized mainframe
To Ordinary Draw Programs, It Could Be ACaterpillar. Introducing ISIS™/Draw: the only drawing program with "chemical intelligence." ISIS/Draw knows structure representation standards—automatically understanding aromaticity, recognizing valence limits, and even sprouting bonds in the proper direction. And because ISIS/Draw runs in a windowing environment, you can cut and
Only ISIS/Draw Knows Its Friedelin.
paste structures and reactions into other application software including word processing, presentation graphics, and spreadsheet programs to create professional-quality reports, documents, and presentations. Plus, you can move structures across different platforms because ISIS/Draw is the only package available on all the popular desktop computers. Your company can finally standardize its chemical drawing system corporate-wide, even if differ— • : —_____ ^~ " ^-'-- ~ ~ •*- ent departments use different == T
computers. Best of all, ISIS/Draw is from Molecular Design Limited, the world leader in chemical information management. As the first building block of our new Integrated Scientific Information System (ISIS)—ISIS/Draw can be your first step towards a complete corporate information solution. For details, call 800-MDL-0064 now. You'll agree, ISIS/Draw is the only intelligent choice.
Always look your best ISIS/Draw helps you quickly and easily create professional-quality presentations.
®
Molecular Design Ltd
Switzerland, (41) 61-632180; England, (44) 252-513054. ISIS is a trademark of Molecular Design Limited.
CIRCLE 8 ON READER SERVICE CARD March 18, 1991 C&EN
23
computers. Added to all this is the growing popularity of laboratory in formation m a n a g e m e n t systems (LIMS) for h a n d l i n g laboratory scheduling and the flow of laborato ry information. The result is an elec tronic babel, with few instruments or computers able to communicate directly or meaningfully with each other. One difficulty is that different makes and types of computers use incompatible operating systems. IBM PCs and compatibles, for exam ple, generally use Microsoft Corp/s MS-DOS. Digital Equipment VAX computers use VMS. Apple's Macin tosh computers have their own. And there are others. A way around the difficulty is to connect the different instruments and computers through a local area network (LAN). Such a network might incorporate just a few instru ments and associated PCs with a PC or workstation as a file server. A large LAN might include a LIMS and have a mainframe computer connected to the network. Different labs can be networked together at a given site, as can different sites within a company. With networking developing in popularity the way it is, industry standards assume a growing impor tance. Various efforts are under way. For example, in Chicago, an initial effort aimed at developing one type of standard was announced by a task group of the Analytical Instrument Association, a 60-member interna tional trade association for manufac turers and suppliers of high-tech nology instruments for chemical analysis. The association's communi cation standard working group in cludes representatives from Beckman, Digital Equipment, Dionex, Hewlett-Packard, Hitachi Instru ments, Perkin-Elmer, Shimadzu Sci entific Instruments, Spectra-Physics Analytical, Varian Associates, and Waters Chromatography Division of Millipore. The first analytical technique to be addressed by ΑΙΑ is chromatog r a p h y — t h e most common tech nique—with other techniques to fol low. What the task group has devel oped is a communication standard for the interchange of chromatogra phy data between instruments and 24
March 18, 1991 C&EN
computer data systems of different manufacturers. A demonstration version has been successfully tested by several vendors, and following review by remaining task g r o u p members, other vendors, and a rep resentative group of end users, a documented standard will be issued. The ΑΙΑ standard for chromatog raphy data communications has two parts. The first is a list of key words (numbers and text) that provide the information to be exchanged be tween the systems. There are four types of information, including raw
data, processed results data, methods conditions, and Good Laboratory Practice (GLP) compliance informa tion. The demonstration version ad dresses the first two types. The sec ond part of the standard is a soft ware utility tool, called netCDF, which provides the simple com mands and internal algorithms to make the format translations be tween the systems. This utility is added to each system. As for individual approaches to networking, different instrument and computer manufacturers are tai loring their approaches with slight ly different twists. These often differ depending on the types of instru ments or computers the vendors make or on differing corporate phi losophies or capabilities. Instrument manufacturer Varian Associates, for example, unveiled in Chicago what it calls its Star net work program to install and support
Instrument makers ponder coming European market With Europe an important market for analytical instruments, manufacturers of those instruments both in the U.S. and in Europe are understandably concerned with developments there. What, for example, will be the effects of the unified market in the European Community coming at the close of 1992? And what busie ness opportunities might spring from the o struggle of Eastern European countries to ;convert centralized communistic sys tems to western-style economies? e Some thoughts on these issues were ivoiced by a panel of analytical instru it ment industry executives at a breakfast e hosted during the Pittsburgh Conference s by Centcom Ltd., the advertising sales n management company for American Chemical Society publications. l·· At one time people feared that the de ν velopments in Eastern Europe would slow Ϊ, down the integration process of the EC, il says Hans-Guenter Hohmann, general s manager of Hewlett-Packard analytical's European business unit. "Time was taken n away from politicians during 1990 in order x to cope with this dramatic change," Hoh h mann says. "But I think they are now back k on track." ), With the opening of Eastern Europe, it Hohmann says, it has become evident h that making up for the social and eco-
nomic differences that developed in the post-World War II period between Eastern and Western Europe will require more to be done than people had expected. But Hohmann is optimistic about the prospects. There is pressure from the people in Eastern Europe to make up the differences quickly, so large investments must also be made quickly to avoid social problems. This, Hohmann believes, offers great opportunities for investors who have long-term views and are willing to work closely with the peopie in those countries, The basic understanding needed, Hohmann says, is that there is a time frame regarding the needs of the countries in Eastern Europe. It means, he says, that certain products will be asked for at certain times. Meanwhile, in Western Europe, the market unification slated for 1992 is drawing nearer. Hermann Vodicka, president of Mettler Toledo Group, challenges at least some of the conventional wisdom about it. The EC currently includes 12 countries with a total population of some 350 million, Vodicka notes, "and you very often read in the media that this is going to be the biggest homogeneous marketplace in the world." The homogeneous marketplace will
Novell/Ethernet local area networks in analytical laboratories (Circle 372). The company says it will team with major network suppliers in the U.S., Canada, and Europe to supply the network products and services. It has signed a letter of intent with NYNEX Business Centers to supply networks throughout the U.S. Varian points out that NYNEX Business Centers has 77 sales branches in 28 states, offering design, installation, support, and maintenance of local area networks as part of its services. Varian notes some of the advantages of a network. For example, data stored on a file server can be shared by anyone on the network. This means that a laboratory manager can access raw, digitized chromatograms or spectra and review, reprocess, and report them from his or her office. Instrument and computer manufacturer Hewlett-Packard, which last come, Vodicka believes, but not so soon and not so comprehensively as the phrase implies. There will be a common tax law, he says, but at different levels, although this by itself is not a reason that a homogeneous market shouldn't be possible. A more important question, Vodicka says, is will there be a common currency? "Not in the next 10 years," he answers, "and perhaps not in the coming 15 to 20 years." Vodicka points out that the strength of a currency is the expression of the efficiency of an economy, and if weaker
year introduced its unified laboratory concept, an instrument/computer/networking strategy for allowing diverse computers to share data, this year brought out a series of HP ChemLAN products (Circle 373) as a part of that concept. Complete HP ChemLAN packages include standard high-speed wiring, industrystandard networking software, and application-specific ChemLAN software. The latter is integrated into the analytical application so networking can be performed within HP ChemStation software. HP ChemLAN automatically converts disparate data-file formats between MS-DOS and an HP 1000 r u n n i n g RTE-A software so data from one can be used on the other. Instrument techniques that can be connected on the network with appropriate server computers are GC, LC, MS, infrared spectrometry, and GC/atomic-emission detection.
economies are added to a strong economy, the performance of the strong economy becomes diluted. That is equivalent to subsidizing the weaker economies. "With the selfishness that is around," he says, "I just don't see that." What has come to be called Fortress Europe will occur, Vodicka believes, since there are strong pressure groups for the trade protectionism the name signifies. So he foresees that because of local-content requirements—percentage figures are being defined now— companies that are inside the EC will have an advantage. The conclusions deriving from all these considerations for his own company, Vodicka says, are that first, the firm will not have only one company in the EC that will do the distribution, marketing, sales, accounting, and so on. Rather, he says, "we will continue in every single country with our affiliated companies. We will continue to maintain warehouses in each country, so as to avoid delays owing to strikes, union activities, or inadequate transportation. We will continue to have various production sites in a number of countries, also so as to cope better with the various labor markets and the unions. Our invoicing will continue in local currencies, through local accounting and collection departments. And even payment terms will continue to be Vodicka: question of common currency
HP ChemLAN provides a number of networking functions, including remote data-file conversion (to convert data from MS-DOS to HP 1000 RTE-A file formats, for example); remote data analysis (to perform data analysis on remote computers with more power than the user's local computer); remote printing (to increase printing speed and quality at lower cost by using one central printer); file transfer (to move data and reports easily and quickly to where they're needed); and logging of network activity (to maintain records of file transfers and errors to ensure data integrity and to help meet GLP requirements). Perkin-Elmer, through its PE Nelson Systems operation, terms its networking approach its Laboratory Computing Architecture. The architecture is designed to provide a systems strategy for automating an entire laboratory or just certain por-
different in those countries. We will continue to recruit local people in each country. . . . We will continue to pay taxes locally, and levels will vary. And we will continue to pay salaries at varying levels in these different countries." Riccardo Pigliucci, vice president of Perkin-Elmer's instrument division, largely agrees with Vodicka that there is not going to be a homogeneous Europe. There are some big impediments, he says, language being one. Although English is becoming more of a standard across Europe, he says, there is no question that salesmen will always be able to sell better in their own languages. And advertising and literature will continue in the various languages. So the cost of translating manuals and turning out brochures will continue. "There's nothing magic that at midnight, Dec. 31, 1992, you can have all English brochures," Pigliucci says. "It's not going to work that way." On currency, Pigliucci believes that maybe there will be a united currency. But even in that case, he says, it would only lead to more pressure for more homogeneous pricing policies around Europe. "The competitive edge," he says, "will remain with the company that has a local presence. Local presence, with local people, will still be the competitive winning edge—even in Europe, even after 1992."
March 18, 1991 C&EN
25
tions. And it provides for entry and evolution at any point, such as an analog-to-digital interface, integrator, PC-based workstation, or VAXbased centralized multiuser system. Some of the new products from PE Nelson are designed to play into that philosophy. One is the Model 1020 Personal Integrator (Circle 374), a unit that takes up only 12 inches of bench space, has a built-in screen, and has a hard disk for longterm data storage. It is designed to be completely compatible with PCs and larger systems and it can be used with all commercial liquid and gas chromatographs. The company's Turbochrom 3 chromatography data system (Circle 375) is also designed with multivendor chromatography automation in mind. It combines PE Nelson chromatography data-handling software, Microsoft Windows software, and IBM PC technology into three new packages: low-cost single instrument, multi-instrument (up to 15), and reprocessing for network applications. It, too, is compatible with all commercially available liquid and gas chromatographs. Synergy is the name Beckman has chosen to describe its concept for networking (Circle 376). It is a plan for using industry-standard PC networks to provide bidirectional communications for Beckman chromatography and capillary electrophoresis s y s t e m s a l o n g w i t h o t h e r Beckman and third-party instruments, for example, to sample management and reporting systems, such as Beckman's PC-based EasyLIMS or Lab Manager LIMS. Beckman, incidentally, has now added a structured query language SQL Pipeline to its Lab Manager LIMS (Circle 377) that provides access to Rdb/VMS (Digital Equipment) or Oracle (Oracle Corp.) databases. As with other computer companies, workstation manufacturer Sun Microsystems is promoting networking, in its case extolling the advantages of UNIX-based workstations over PCs. UNIX, it points out, facilitates hardware connection to a network through the ability to communicate with DOS. And since the workstations are more powerful than PCs, the company says, they provide something of mainframe power at near PC cost. They have 26
March 18, 1991 C&EN
the capability for multitasking (simultaneously running a number of applications using the workstations' windowing capabilities); they can control up to 20 instruments; they can do compute-intensive work like molecular modeling; and they can handle gigabyte-size databases. At the Pittsburgh Conference, Sun provided the computing showcase for software written by other parties for its workstation UNIX platform. Among them were three new products: • Xerox Chemical Illustrator, first introduced by Xerox Corp. in 1990 for the Xerox 6085, 6085 Model 2, and PC AT compatibles, is now available on Sun UNIX workstations (Circle 378). It is a drawing tool for creating chemical structures, and allows a user to select easily from among 70 different types of bonds and rings, with user-defined defaults for size, width, and constraint angles. It includes a large set of editing features. • Daylight Chemical Information Systems Inc. has a set of three chemical software tools available now for the Sun UNIX platform: Smiles, a chemical structure specification language designed for chemical information processing; Thor, a structureoriented database system that, using Smiles as a primary key, is designed for fast, consistent retrieval of a variety of data types in databases of any size; and Castor, a compact chemical database designed as a reference tool for chemists (Circle 379). • Labtech Chrom/RT, introduced by Laboratory Technologies Corp., is a comprehensive chromatography software package that combines realtime data collection, peak integration, report generation, and LIMS support into one package (Circle 380). A multi-instrument program, it runs on all standard computer platforms, including UNIX, DOS/Windo ws3, and OS/2.
A good example of the trend toward software being written for multiple platforms comes from Molecular Design Ltd. In Chicago, MDL introduced ISIS/Draw, a new chemical drawing package that is the first part of a new integrated scientific information system, t h e whole scheduled for introduction in April at the national meeting of the American Chemical Society. Designed to help chemists create chemical structures and reactions rapidly, ISIS/Draw (Circle 381) recognizes structure representation standards, hence automatically positions atoms and bonds the way a chemist would, MDL says, sprouting new chemical bonds in a chemically logical direction. It also understands aromaticity and places double bonds accordingly, and it automatically places hydrogen bonds properly. It knows how bonds should fuse as structures are built up with templates, and it recognizes valence limits, warning if a limit is exceeded. MDL says a major benefit of ISIS/ Draw is that it runs in the windowing environment of the major computing platforms. It has the same look and feel on each platform, MDL explains, although it adheres to the standards of the windowing environment for that platform. The Macintosh version, MDL says, looks like a Macintosh program, and the Microsoft Windows version looks like a Windows program. The advantage for the corporate user, MDL says, is that a company need offer only a single set of training and internal support programs, regardless of which platforms individual sites or departments use. As for the multiple platforms, ISIS/Draw will be available for Apple Computer's Macintosh workstations, IBM PCs and PS/2s running Microsoft Windows on DOS, Digital Equipment's VAX/VMS workstations, IBM PS/2 workstations running Presentation Manager on the OS/2 operating system, HewlettPackard's HP 9000 graphic workstations running the HP-UX operating system, and Fujitsu's FMR line of PCs through the Kanji version of Microsoft Windows. Microsoft Windows and Macintosh versions will be the first releases, with the remainder available later in 1991. •
New
New
^KBBBSSmki
i^Bmsia
Text
Text
$$M%Mi$$ä&-s .
i.imiB&BBB^Bm
1 • >^:^^^^·ϋψ^ϊν^
CE
PC-based LIMS
GE
wm:'^-
n
EasyLIMS" HPliC
Systeri Gold
Your productive link to industry standard computing in separation science Finally, you're free to automate multi ple laboratory operations your way using the most popular hardware and software available. Synergy™ is a coor dinated plan that allows you to con nect multiple existing LC's, GC's and other instrumentation to our versatile laboratory information management systems, PC-based EasyLIMS™ or VAX*-based Lab Manager™ LIMS. You can also connect System Gold™ HPLC with P/ACE™ Capillary Electrophoresis—a combination of two complementary technigues with single-point control for advanced LC/CE automation. The synergistic possibilities are endless and the choice is yours.
The results: • Increased productivity through "paperless" operation of your lab, from sample receipt to sample reporting. • Dramatic savings from greater sample throughput. • Enhanced data integrity via auto matic transfer of sample results from instruments to LIMS. • Better GLP/GMP compliance from improved control over data, methods and reports. • Improved decision making capabili ties with immediate access to sample information. CIRCLE 3 ON READER SERVICE CARD
Synergy. The coordinated plan that gives you the freedom to use stand ard computing platforms to create powerful instrument networks. It's our commitment to be your productive link to industry standard computing in separation science. For the synergistic details, contact Beckman Instruments, Inc., 1050 Page Mill Road, Palo Alto, CA 94304. (415)857-1150.
BECKMAN *VAX is a trademark of Digital Equipment Corporation.
Capillary electrophoresis While exhibitors were showing new instrument developments in capil lary electrophoresis on the exposi tion floor, speakers in the technical sessions were reporting on new ap plications of the various techniques. Among them: • Norberto A. Guzman, analytical biochemist at Hoffmann-La Roche, Nutley, N.J., described an analyte concentrator that he uses to isolate preparative amounts of purified an tibodies or other proteins. • Analytical chemistry professor Lloyd M. Smith of the University of Wisconsin, Madison, told his audi ence that capillary electrophoresis can sequence DNA 100 times as fast as slab gel methods. • Tshenge Demana, a graduate student in the group of analytical chemistry professor Michael D. Morris at the University of Michi gan, Ann Arbor, said that a modula tion in analyte velocity speeds sepa rations and improves resolutions of DNA fragments. • Analytical chemistry professor James W. Jorgenson of the Universi ty of North Carolina, Chapel Hill, has improved separations of very similar proteins by a two-dimen sional coupling of high-perfor mance liquid chromatography with capillary electrophoresis. • Chemistry professor Shigeru Terabe of Himeji Institute of Tech nology, Japan, told of the thermody namic studies that led him to cau
tion the need for tight temperature control in the micellar electrokinetic chromatography (MEKC) method that he pioneered. • Jinping Liu, a graduate student with analytical chemistry professor Milos V. Novotny at Indiana Uni versity, Bloomington, reported the application of Novotny's new fluo rescent derivatizing reagent to sepa rations of simple sugars and biologi cally important oligosaccharides. • Also in Novotny's group, post doctoral fellow Jiri Snopek, who is on leave from Charles University, Prague, Czechoslovakia, has used cyclodextrins as aids in resolutions of enantiomers. The current intense interest in capillary electrophoresis exempli fied by these research results stems from the technique's remarkable separation capabilities: It's possible to develop millions of theoretical plates in reproducible, quantitative ly reliable separations of attomole (10~18 mole) amounts of proteins, DNA, carbohydrates, and monomolecular compounds in minutes to less than an hour. Variants include use of open-tube capillaries, polyacrylamide gel-filled capillaries, sur factants for the MEKC of Terabe's,
Capillary electrophoresis sequences DNA
_Ji JU
k-Λ X
JLJJ i
L
I
G A A T T C . G A G C T C G G T A C C C G G G G A T C C T C T A G A G T C Schematic representation of data indicating the sequence of the first three dozen bases of a bacteriophage M13 derivative 28
March 18, 1991 C&EN
and isotachophoresis ("same-speed migration") for preconcentration of analytes. The small sample requirements of capillary methods are a boon to biol ogists studying vanishingly small amounts of rare compounds. Indeed, analytical chemistry professor An drew G. Ewing of Pennsylvania State University has analyzed con tents of cytoplasm from single neu rons this way. But the small sample capacities also limit chemists' ability to detect or study further such small amounts. This is the problem that Guzman of Hoffmann-La Roche set out to solve with his analyte concentrator. While still at Princeton Biochemicals in New Jersey, Guzman devised a minute chamber in line with the capillary to accumulate certain sub stances from successive analyses to collect microgram amounts. His col laborators were biochemist Maria A. Trebilcock of Princeton Biochemi cals and veterinarian Juan P. Advis of Rutgers University. In his Pittsburgh Conference pa per, Guzman described filling the chamber with immobilized protein A from Staphylococcus aureus. Protein A has an affinity for immunoglobu lin A, so antibodies from biotechnological samples accumulate there. Guzman has also immobilized mono clonal antibodies in such chambers to concentrate the particular ana lytes that they bind. The Nutley investigator treats particles of control-pore glass with γ-aminopropyltriethoxysilane to coat surfaces with 7-aminopropyl groups. He next treats particles with p-phenylene diisocyanate, which yield p e n d a n t isocyanatophenyl groups. He finally treats the parti cles with protein A or antibody, whose molecules bind to particle surfaces through pendant or termi nal amino groups. He begins constructing the ana lyte concentrator chamber by put ting glass beads into a segment of capillary. Heating sinters these to a porous glass frit that seals one end of the chamber. He then puts the control-pore glass particles into the capillary. Finally, he seals them in side with a second plug of sintered glass beads. Guzman described use of a pro-
earch the Chemical Journal Files on STN International ! On STN International, youll find full-text information from primary journals published by some of the world's leading scientific organizations. They're valuable sources for the comprehensive information you need, such as experimental procedures and data, new chemical names, etc. Importantly, they provide you with the original article in its entirety. Full-text chemistry databases on STN include: CJACS—Produced by the American Chemical Society, GACS is available only on STN. GACS contains the complete—and searchable—Englishlanguage text of the 22 ACS Primary Journals, including more than 90,000 records from 1982 to present. CJAOAC—CIAOAC is produced by the Association of Official Analytical Chemists. This database provides the full-text of the peer-reviewed Journals of the Association of Official Analytical Chemists. More than 907 records dating from 1987 are contained in GAOAC. CJELSEVIER-The GELSEVIER database contains full-text records from publications of Elsevier Science Publishers B.V. More than 2,400 records dating from January, 1990 will be added yearly to the database. Citations in GELSEVIER are in English, French, and German. CJRSC—This English-language file contains documents published in ten peer-reviewed journals of The Royal Society of Chemistry. GRSC contains more than 10,000 records covering 1987 to the present.
YES! I'd like further information on full-text chemistry searching on STN,
CJWILEY-The GWILEY database contains documents published in five polymer journals of John Wiley & Sons, Inc. More than 5,000 records of full-text articles, communications, and notes are contained within GWILEY.
Name Title Affiliation
I I
Address
I
Telephone.
I
CJVCH—An English-language database, GVCH contains records for documents published in Angewandte Chemie and provides access to research papers in the field of chemistry. GVCH is produced by VCH Verlagsgesellschaft in the Federal Republic of Germany.
Mail to: STN International c/o Chemical Abstracts Service Marketing Dept. 39190 P.O. Box 3012 Columbus, OH 43202 USA
It's easy to get started searching full-text databases on STN. Simply fill out the attached coupon and we'll send you a complete kit of information on the databases listed above and an STN sign-up kit.
STN INTERNATIONAL
POLYMERS & PLASTICS New books from the American Chemical Society
Fire and Polymers: Hazards Identification and Prevention Gordon L. Nehon, Editor This new volume provides an examination of the ongoing research in fire andpolymers. Thirty-four chapters are divided into five sections covering: fire toxicity; fire retardants and fire retardant commodity plastics; fire retardancy in engineering plastics; fire and cellulosics; fire performance, test, and risk. ACS Symposium Series No. 425 640 pages (1990) Cloth. ISBN 0-8412-1779-3 $99.95
Barrier Polymers and Structures William J. Koros, Editor Provides solid coverage on this rapidly changing field. Offers discussions on structure-property relationships of Saran materials and nylons, approaches to engineering around the sensitivity of barrier polymers to humidity, characterization of sorption kinetics in several glassy polymers for a broad spectrum of penetrants, complex barrier structures, and flavor scalping. ACS Symposium Series No. 423 416 pages (1990) Cloth. ISBN 0-8412-1762-9 $89.95
Sound and Vibration Damping with Polymers Robert D. Corsaro and L.H. Sperling, Editors This state-of-the-art volume examines blends and interpenetrating networks for their ability to damp over broad temperature and frequency ranges. Background material is presented as well as information on fillers, plasticizers, additives, new instrumentation, and theory. ACS Symposium Series No. 424 480 pages (1990) Cloth. ISBN 0-8412-1778-5 $99.95
Handbook of Plastics Testing Technology Vishnu Shah Offers up-to-date methods and guidelines for testing plastics. Provides step-by-step methods for accurately testing the five basic properties of plastics: mechanical, thermal, electrical, weathering, and optical. Covers tests for tensile strength, elevated temperature performance, electrical resistance, dielectric strength, photoelasticity, flammability, and water absorption. Published by Wiley-Interscience 493 pages (1984) Cloth. ISBN 0-471-07871-9 $89.95
Bonding Energetics in Organometallic Compounds TobinJ. Marks, Editor A broad, up-to-date, and in-depth overview of the current state of knowledge in this field is the focus of this new volume. It brings together carefully reviewed contributions from leading experimental researchers studying organometallic bonding energetics in the gas phase, in solution, and on well-characterized surfaces. The latest theoretical developments are also presented. ACS Symposium Series No. 428 292 pages (1990) Cloth. ISBN 0-8412-1719-2 $64.95
Rubber-Toughened Plastics C. Keith Riew, Editor Examines the development of theoretical and practical approaches of toughness and improvements for both thermosets and thermoplastics. Three major themes focus on fracture mechanics and failure mechanisms vs. toughness; morphology and mechanical properties vs. toughness; and chemistry and physics of toughening vs. toughness. Advances in Chemistry Series No. 222 468 pages (1989) Cloth. ISBN 0-8412-1475-1 $89.95
Agricultural and Synthetic Polymers: Biodegradability and Utilization J. Edward Glass and Graham Swift, Editors Offers an unbiased review of biodegradable synthetic polymers and polymers from renewable resources. Examines the state-of-the-art in commodity plastics degradation and disposal, and the greater utilization of agricultural polymers in industrial applications. Biodegradation, photodegradation, and chemical degradation are addressed and various uses for agricultural polymers are explored. ACS Symposium Series No. 433 328 pages (1990) Cloth. 0-8412-1816-1 $69.95
To order CALL TOLL FREE 1-800-227-5558 In Washington OX. area call 872-4363 or mail payment to: American Chemical Society, Distribution Office, Dept. 75,1155 Sixteenth Street, NW, Washington, DC 20036
The Best Software for Chemists at t h e Best Prices from The American Chemical Society ACS Software brings you two of the most popular software programs for analytical chemists... Analytical Chemistry by Open Learning (AC0L) Gets up to speed on major analytical methods With this interactive software/text teaching tool, you can quickly learn how to operate analytical instruments with skill and proficiency. ACOL provides ideal training for technicians and scientists, covering both the philosophy and basics of the best-known instrumentation techniques. Realistically simulates the analytical environment ACOL modules provide training, continuing education, and updating in seven of the most widely used analytical methods. Each package consists of a software-based training disk and a text that complements it. The software offers interactive experience in making decisions during an analysis, and provides immediate feedback on the computer screen, simulating instrument output. ACOL programs cover seven top analytical techniques • • • • • • •
Atomic Absorption Spectroscopy Gas Chromatography High Performance Liquid Chromatography Polarography Radiochemistry Fluorescence Spectroscopy Quantitative IR and UV
Software and book (all programs); books also sold separately, call for full details. Tor each program: List price $395 Member price $335 Academic price $295
UN-PLOT IT Plus Automated digitizing for PCs and MACs Mow you can automatically digitize strip chart output, (x,y) recorder output, instrumental output, published graphs, old graphs, shapes, figures, and just about anything else. The data is saved in ASCII format and an be imported into almost any commercial graphics package. You can also use our software to re-scale and re-plot graphs, integrate peak areas, smooth data, perform regression analysis, take derivatives, etc. Simple, logical menus make the use of Vfi-PLOT-IT-Plus a breeze. Choose from "line follow" mode, raster scan mode, and manual mode to match your data and your requirements. In addition, UN-PLOT-IT Plus delivers accuracy of 0.05 mm; speed of up to 200 points per minute; the ability to store up to 5,000 data points; and much more. List price $385 Member price $325 ia Academic price $345
2819 489.8966 38.32133
Hardware requirements: IBM: IBM PC and compatibles, HPGL compatible; pen plotter
J^L^JuJ
Mac: Any Macintosh; 256K RAM; pen plotter. Produced by: Silk Scientific, Inc.
Hardware requirements: IBM PC or compatibles; EGA or VGA graphics board; color monitor. Produced by: ACOLf Thames Polytechnic
To order these and other ACS Software products, call TOLL FREE 1-800-227-5558. In Washington, DC, call (202) 872-4363. Or fax your order to (202) 872-6067.
ROSPECTUS PRODUCT PROSPECTUS
Try on aM our Tebol 99 application hats... Get your FREE, 8-page brochure full of Tebol 99 high-purity TBA* facts and chemical applications.
How to Succeed atGC Fittingly, Tebol 99 alcohol improves products, increases yields, shortens reaction times, lowers ethylene pressures, raises molecular weights, lowers gel requirements, completes monomer conversions, and much more. to//ARCO Chemical now, tollfree, at 1-800-321-7000. And try Tebol 99 alcohol on for size. Or, simply circle the Reader Service number for the new, 8-page Tebol 99 alcohol brochure.
Send for our new 8-page, 4/color brochure detailing the proper calibration gas mixtures, carrier and fuel gases, and equipment necessary for success in gas chromatography. The brochure lists 11 common detectors and indicates the preferred gases and applications. Also offered are additional publications that will be useful in your work with GC. To get your free copy, circle the Reader Service Number.
„*Su"* * « *
J®**0*m
ertiary Butyl Alcohol
Matheson
ARCO Chemical
c
'Gas Products
W o r l d Leader in Specialty G a s e s & Equipment
30 Seaview Drive · Secaucus, NJ 07096-1587
CIRCLE 29 ON READER SERVICE CARD
CIRCLE 29 ON READER SERVICE CARD
Now Available from Air Products.
PFANSTIEHL
Economical Mixed Polycycloaliphatic Amines
The Start Of Something Big: Ribonolactone D-Ribono-1, 4-lactone and its 2,3-O-isopropylidene derivative have been the starting points for the synthesis of a wide variety of natural products, C-glycosides and carbocycles. We now offer both of these important chiral starting materials, in addition to our wide selection of other sugar lactones. All are available in quantities to meet your needs; research through scale-up. Write or call for a technical brochure and price list and see how Ribonolactone can be the start of something big for you.
MPCA Composition
Η,Ν
^ ^ Η,Ν
Η Λ Γ " ^ H,N
Samples Available. Other Dia m ines a va ila ble. Call us at 1-800-345-3148 or 1-215-481-6799 More than chemicals.Chemistry.
PRODUCTS
t^
D1991 Air Products and Chemicals, Inc.
CIRCLE 2 ON READER SERVICE CARD
PFANSTIEHL LABORATORIES, I N C . The source for carbohydrate chemistry 1219 Glen Rock Avenue/Waukegan, IL 60085-0439 Tel.: 1-708/623-0370ΑΤΌΙΙ Free: 1 -800/383-0126 FAX:708/623-9173/Telex 25-3672 Pfanlab 75-P
MAKING TMII6S WORK CIRCLE 16 ON READER SERVICE CARD
CIRCLE 20 ON READER SERVICE CARD
Now handle small volume pressure reactions.
PARR BENCH TOP MICRO REACTORS Parr's Series 4590 25 ml or 50 ml Micro Reactors handle liquids and gases under heat and pressure with vigorous stirring and automatic temperature control. They are rated for use at a maximum 3000 psig (20.68 Mpa) working pressure at 275°C. Simple, easy operation is due in part to unique screw cap closure and convenient well placed controls. Very little space is needed on bench, within fume hood or glove box. Call or write for Bulletin 4590. PARR INSTRUMENT COMPANY 211 Fifty-Third Street Moline, IL 61265 309-762-7716 Telex: 270226
CIRCLE 28 ON READER SERVICE CARD
tein A chamber to study antibodies of patients with light-heavy chain defects. He also used antibodies against methamphetamine to dem onstrate detection of that substance in urine. While accumulating anti gen-antibody complexes in the con centrator, he carries out electro phoresis with a sodium tetraborate buffer at pH 8.3. When ready to elute the concentrated antibody or other analyte for detection and fur ther study, he changes to a sodium acetate buffer at pH 3.8. He can prepare l-μζ amounts of materials in 15 hours of successive injections. This is enough for such further studies as mass spectrome try. Alternatively, he performs suc cessive injections until the amount of material eluted from the concen trator can be detected by fluores cence with conventional light sourc es, avoiding costly lasers. In addition to studying contents of single cells, Guzman says concen trators might be used to characterize samples from in-vivo microdialysis in brains of animals (C&EN, Dec. 3, 1990, page 29). In this technique, a hair-thin probe is surgically inserted into a target tissue. Buffer flows down an outer portion and any add ed drug or test compound enters tis sue fluid by osmosis t h r o u g h a membrane. Drug metabolites, hor mones, or neurotransmitters of in terest pass by osmosis from tissue fluid into the probe and are carried out for analysis in 100-femtogram amounts. The acceleration in DNA sequenc ing reported by Smith of Wisconsin points the way toward improved techniques that will be needed for the human genome project. Work ing with graduate students John A. Luckey and Howard Drossman, in strumentation specialist Anthony J. Kostichka, research professor David A. Mead, and undergraduates Jon D'Cunha and Tracy B. Norris, Smith used the DNA sequencing chemis try now available on automated slab gel sequencers. This chemistry involves four dif ferent reactions to incorporate the four bases of DNA into fragments for detection. The Madison scientists insert the DNA segment to be se quenced into single-stranded bacte riophage M13mpl9 and infected Es
555, and 590 nm, respectively. The resulting capillary gel electropherogram is a series of peaks of different "colors." Each sequential peak rep resents a fragment of DNA of mo lecular weight one nucleotide long er than the previous one. The se q u e n c e of c o l o r s e n a b l e s t h e Wisconsin researchers to read out the DNA sequence. One advantage of Smith's tech cherichia coli bacteria with the phage. nique is that with improvement, sci They then incubate the phage am entists may be able to use the phage plified in the culture with a short, from one plaque on a petri dish of E. fluorescently labeled primer se coli, rather than go through exten quence, a DNA polymerase called sive cloning. This would shorten the Bst, and four deoxyribonucleotides time and lower the cost of sequenc bearing adenine, cytosine, guanine, ing. Each plaque of phage on a "lawn" of E. coli contains 1 ng of and thymine. In one of the four reactions called DNA, w h e r e a s S m i t h ' s m e t h o d the adenine reaction, for example, needs 4 ng. Ironically, the success of the capil the Wisconsin research workers add less of deoxyadenylic acid than of lary gel electrophoretic method the others and also include dide- leads Smith to think that the future oxyadenylic acid. At each point may lie in a return to slab gel tech where the bacteriophage template niques with ultrathin, 10- to 100calls for adenine, the lesser concen tration of deoxyadenylic acid slows the rate of incorporation, and there Reductive amination forms is then an increased probability that dideoxyadenylic acid might be in amino sugars... serted instead. A DNA fragment with dideoxyadenylic acid at the end CH2NH2 QHO could not propagate beyond that OH 4-OH NH 3 point. HO^HO 0 H The product of this reaction is NaBH3CN +OH thus a mixture of roughly equal OH OH amounts of DNA fragments from CH2OH CH2OH several to 800 nucleotides in length, all ending with dideoxyadenosine. . . . which can form Three other reactions with dideoxyfluorescent derivatives cytidylic, -guanylic, or -thymidylic acids are also carried out. The prod C0 2 H ucts of all four reactions are com bined. The primer for each reaction is covalently labeled with a different flu orescent dye from among fluoresce in, Z ' ^ - d i m e t h o x y - O ' - d i c h l o r o fluorescein, tetramethylrhodamine (with four methyl groups replacing the ethyls of rhodamine B), and rhodamine X. Nicknamed FAM, JOE, TAMRA, and ROX, derivatives of these dyes suitable for linking are available from Applied Biosystems, Foster City, Calif. Smith designed a detector for cap illary gel electrophoresis with 50-50 N-sugar beam splitters, band pass filters, and photomultiplier tubes to detect fluo rescence from each dye at 495, 525, March 18, 1991 C&EN
35
μπι-thick gel slabs on optically pol ished glass. This is because the speed of current sequencing ma chines results from running many sequencings on parallel tracks of the same slab. The corresponding ma chine for capillary work would need many parallel capillaries, which might be difficult to achieve. Such ultrathin slabs could dissi pate heat from high electric fields efficiently, so that the same 5- to 30kV fields might be used in slabs as with capillaries to attain the speed of capillary separations. Smith's group has achieved sequences of 400 bases in 25 minutes on ultrathin slabs. Assuming slabs might be made reusable and that sequences can be run on 50 parallel tracks per slab, he estimates that sequences of 600,000 bases per day is theoretical ly possible. Speeding the separation of DNA fragments at improved resolution is the object of Morris7 group at Michi gan. The method described by his graduate student Demana is analyte velocity modulation. Working with graduate students Maureen Lanan and Chang-Yuh Chen, Demana uses a signal genera tor to superimpose a sine wave of 500 volts per cm peak-to-peak am plitude and 107 Hz over a constant 250 volt-per-cm constant dc field. The overall effect of this is to move DNA molecules forward through the gel and then move them back ward part of the way. During the motion forward, the
molecules become highly oriented. The backward motion allows them to relax. The result is faster motion through the gel network. Demana says the sine-wave signal allows the coupling of the alternating field with molecular motions to occur more efficiently than the squarewave signals others have used. Also, by arranging detection at the frequency of the ac field, the de tector can more narrowly focus on small amounts. The narrower focus of analyte velocity m o d u l a t i o n might lend itself to detection of DNA fragments by ultraviolet absorbence rather than fluorescence. Improving resolution of capillary electrophoresis is also the aim of Jorgenson of Chapel Hill. His solution is development of two-dimensional methods in which the output of one technique such as HPLC is further analyzed by capillary electrophore sis. Jorgenson described progress with this approach in work with re search professors Michelle Bushey and Curtis Monnig and graduate students Alvin Moore and Anthony Lemmo. The aim of the project was to in-
Analyte concentrator accumulates antibodies in sample for later elution at a different pH Capillary wall
Antigen (protein A)
Antibody
Controlled-pore glass particle
Porous glass frit
Antibody 36
March 18, 1991 C&EN
crease peak capacity, which is the number of peaks that can be separat ed in any one HPLC column or elec trophoresis capillary. The peak ca pacity of a two-dimensional method is the product of the two individual peak capacities. Thus, by combining two methods with peak capacities in the h u n d r e d s , one can devise a method with total peak capacities in the tens of thousands. This approach assumes that peaks are uniformly distributed over the range of each method. In actual practice, it usually turns out that peaks are bunched in regions, lead ing to a residual overlap of perhaps one third of peaks if there are truly tens of thousands of components present. Jorgenson reminded his listeners that to be truly successful, the two dimensions of a separation should be orthogonal. By this he means that the two methods used should sepa rate components according to com pletely different physicochemical properties. Reversed-phase HPLC separates components according to hydrophobicity, whereas capillary electrophoresis separates them by electrical charge and somewhat by molecular size. The North Carolina chemists pass the eluant from HPLC through a six-port valve. They collect one min ute's eluant in a 10-μί loop in the valve. Then they rotate the valve to pass the contents of the loop past the opening of the electrophoresis capillary. Though most of the loop content is rejected as waste, the whole loop passes past the capillary opening so that the whole loop is sampled. By this method, the Chapel Hill workers are able to distinguish be tween horse and bovine heart-cytochrome C, which differ by only three amino acids in a sequence of 104. They digest the two proteins with trypsin. Two-dimensional HPLC-CE contour maps show peaks characteristic of each. And recasting the data in a so-called gray-scale map gives instant visual recognition of tailing of some peaks. Still, Jorgenson is working to in ject the entire contents of the loop into the capillary for truly complete sampling. In one approach, his group adsorbs the contents of the
O^COMVt i*Ci4/ 4^ciutici^l
New SFE system extracts your samples in minutes, not days Say goodbye to tedious liquid-extraction sample prep for GC, HPLC, and UV-vis analyses. Supercritical fluid extraction (SFE) is faster and more efficient; uses inexpensive, nontoxic solvents like CO2; and allows easy control of selectivity via fluid pressure/density. And with Isco's new extraction system, SFE just became even more powerful and accessible.
Ρρ*~~ ^ftf^
•:,;
•
The SFX™2-10 extractor uses quick-load sample cartridges up to 10 ml. Two independent extraction chambers give you efficient, continuous operation.
•
Capture extractants off-line in minimal solvent volume for immediate analysis.
•
New high-capacity syringe pumps handle any SFE or SFC technique at flows from 0.1 μΐ to 40 ml/min and up to 10,000 psi.
W^£
Digital multi-pump controller lets you quickly set up and recall extraction conditions, including programmable modifier addition. CIRCLE 35 ON READER SERVICE CARD
Phone today, (800)228-4250. Isco, Inc. P.O. Box 5347 Lincoln NE 68505 Tel: (402)464-0231 Fax: (402)464-4543 Isco Europe AG, Briischstr. 17 CH8708 Männedorf, Switzerland Fax: (41-1)920 62 08
ISCO
loop in a minute cartridge of HPLC column packing material placed at the opening of the capillary. Then they elute all of the adsorbed substances into the capillary with an aqueous-organic solvent mixture. Use of the absorption cartridge increases sensitivity 100 times, according to Jorgenson. His group can detect the naphthalenedialdehyde derivative of glycine at 2 X 10~8 mole this way. Though electrophoresis generally uses capillaries up to 100-cm long, those of the North Carolina group are only 15-cm long. This is because electrophoresis must be complete in 55 seconds to analyze the next minute's eluant from HPLC. Even faster electrophoresis in very short capillaries might come from a multiplex method developed at UNC. The group focuses a laser on a length of capillary only 1.2-cm long. They use a beam splitter to divide the laser beam into one beam of 92% strength close to the injection point and a second beam of 8% slightly farther down. Then they inject fluorescein derivatives of glycine, arginine, and phenylalanine continuously into the capillary. The first laser beam "bleaches" the fluorescence by saturating excited states. At intervals, the researchers turn off the bleaching beam. The concentration of ground-state molecules passing through the capillary increases. These are detected by the second beam as a probe beam. The research workers alternate between bleach and no-bleach at a certain frequency and transform the data to yield an electropherogram. This multiplexing method is so fast that they are able to see cis and trans forms of an alanylproline derivative. This offers possibilities of studying kinetics of conformational changes occurring on a time scale of seconds. The reason that investigators are able to use high electrical fields in capillary electrophoresis stems from uniform heat dissipation from capillaries only 80 jum in diameter. Thus, no temperature gradients or laminar flow results that might degrade resolution. But heating from the electrical field, called joule heating, does occur, l e a d i n g to t e m p e r a t u r e changes. 38
March 18, 1991 C&EN
Terabe of Himeji Institute studied enthalpies and entropies of dissolution of analytes in surfactant micelles. His work demonstrates the importance of controlling temperature in micellar electrokinetic chromatography. He measures the relative retention times of water solvent, micelles, and a series of alkylphenol analytes at different field strengths. These enable him to calculate capacity factors and distribution coefficients, which are proportional to enthalpies and entropies of dissolving phenol molecules in micelles. They are also inversely proportional to the absolute temperature in the capillary. This indirect measurement of capillary temperature has guided Terabe to cool the capillary to values that yield favorable enthalpies and entropies for good resolution of the phenols. The Himeji investigator credits tight temperature control to use of a P/ACE System 2000 instrument, which features liquid rather than air cooling. Liu of Indiana reported on the extension of Novotny's fluorescent reagent to detection of carbohydrates (C&EN, Nov. 5, 1990, page 35) in work with graduate student Osamu Shirota. Oligosaccharides are important in pathogen-antibody binding, cell-cell recognition, and functions of receptor proteins bound to cell membranes. Studies of such oligosaccharides are difficult, because they lack convenient chromophores for detection. Novotny's reagent is 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde. The aldehyde and benzoyl carbonyl groups react with primary amino groups of such sugars as glucosamine and galactosamine to form l-(4-carboxyphenyl)pyrrolo [3,4-b]quinolin-2-yl derivatives. Liu treats such sugars as glucose with sodium cyanoborohydride and ammonia, which convert the aldehyde to an
aminomethyl group for reaction with the reagent. The pyrroloquinolinyl derivatives are fluorescent, whereas the derivatizing reagent is not. Also, fluorescence occurs at about 450 nm (blue), which is within reach of a 442-nm helium-cadmium laser but far away from 220-nm fluorescences of peptides in glycoproteins. Research Corp. Technologies, Tucson, has filed for patents on this reagent and will license them on behalf of Indiana University.
Six-port valve weds LC to capillary electrophoresis Buffer solution Electrophoresis capillary
From liquid chromatograph Waste •
Running mode: Eluate from liquid chromatograph (red) flows through 10-JLLL loop and out to waste Buffer solution (green) flows past opening of electrophoresis capillary, some is taken into the capillary and the rest goes to waste Buffer solution Electrophoresis capillary Loop Paper wick
From liquid chromatograph
\ WasteInjection mode: Buffer solution displaces 1 0-|LLL aliquot from loop past opening of electrophoresis capillary, where some of it is taken in Meanwhile, eluate from liquid chromatograph flows directly to waste
DIALOG GIVES YOUR NEW PRODUCT HELP AT EVERY TURN.
These days, finding your way through the maze of govern merit regulations, patent developments and marketplace tracking is next to impossible without up-to-the-minute, accurate information. That's where DIALOG comes in. After all, for vital chemical, regulatory and business data, where else would you look than in the world's largest online information service? Only DIALOG offers immediate access to thousands of industry and trade journals covering all the latest developments in the chemistry field. With DIALOG, all you need is a PC to check new patents and trademarks, identify chemical structures graphically or gather
research on environmental issues. You'll even locate the latest research results before they're published, by scanning conference papers from sessions worldwide. But you won't waste a minute plowing through irrelevant material, because DIALOG helps you go straight to your specific need. So if you're involved in bringing a new product to market, ask your corporate librarian or information specialist about DIALOG. You may also contact us directly at 800-3-DIALOG (800-334-2564) or FAX at 415-858-7069. Call now. Because the sooner you get the information you need, the
^ ^ 1 ^ 3 1 ^ T ^ ^ INFORMATION SERVICES, INC.
SOOner yOU Can
M ^ W H A A ^
return to work.
Bringing you the world's knowledge.
A Knight-Ridder Company |£G
©1990 Dialog Information Services, Inc. 3460 Hillview Avenue, Palo Alto, 94304. All rights reserved. DIALOG is a servicemark of Dialog Information Services,Inc..Registered U.S. Patent and Trademark Office.
CIRCLE 6 ON READER SERVICE CARD
Snopek worked on resolution of racemates with graduate student Helena Soini of the University of H e l s i n k i , F i n l a n d , w h o is also spending some time in Novotny's group. Such resolutions by capillary methods could find use in studies of chiral drugs in order to meet forthcoming Food & Drug Administration requirements for information about contents of individual enantiomers. The Indiana workers use a form of electrokinetic chromatography with cyclodextrins in place of surfactants, a-, j8-, and 7-cyclodextrins are cyclohexa-, -hepta-, and -octaglucosides, respectively. Roughly cylindrical in shape, their molecules bear hydrophilic hydroxyl groups on outside surfaces and have hydrophobic interiors. Samples studied are various mixtures of the racemic drugs chloramphenicol, ketotifen, pseudoephedrine, and thioridazine. The Bloomington workers find that addition of methyl- or hydroxyethylcellulose to cyclodextrin solution aids separation of enantiomers. The researchers have developed a two-dimensional method in which electrophoresis in a capillary with 7-cyclodextrin is followed by further separation in one with 2,6-dimethyl-0-cyclodextrin. They also have devised an analyte preconcentration technique involving capillary isotachophoresis. In isotachophoresis, a zone of sample is sandwiched in the capillary between zones of leading and trailing electrolyte. Though the leading and trailing electrolytes have different electrophoretic mobilities, migration of all three zones occurs at the same speed. This is because a separation of zones would lead to loss of electrical conductivity. In addition, components of the sample zone become separated and focused into narrow bands. Preconcentration into narrow bands reduces the amount of sample needed for subsequent capillary electrophoresis. Moreover, the electrophoresis step can be done in the same capillary as the isotachophoresis. In this version of a two-dimensional method, the electrophoresis step adds the needed selectivity. • 40
March 18, 1991 C&EN
Hadamard-transform spectroscopy The number of research groups using Hadamard-transform spectroscopy continues to grow, and some of these reported their progress in Chicago. Applications are divided between acquisition of many spectral lines at once and reduction of damage to samples by laser light. The technique has been commercialized in a series of new instruments. On the exposition floor, D.O.M. Associates, of Manhattan, Kan., showed a dispersive nearinfrared Hadamard-transform spectrophotometer, a stationary Hadamard-transform interferometer, and a Hadamard-transform Raman instrument for a neodymium-YAG (yttrium-aluminum-garnet) laser. Meanwhile, in the technical sessions, graduate students from the group of analytical chemistry professor Michael D. Morris at the University of Michigan, Ann Arbor, described formation of two- and threedimensional Raman spectroscopic images. Also, chemistry professor Thomas J. Vickers of Florida State University, explained how to distribute laser power over sample surfaces to minimize damage. And workers in the group of chemistry professor William G. Fateley at Kansas State University, discussed refinements in Hadamard instrumental methods to acquire spectra. In Hadamard-transform spectroscopy, masks with patterns of lighttransmitting and opaque slits are used to project patterns of light onto a sample. The changing patterns of transmitting/opaque slits encode the light according to a matrix of ones and zeroes of a matrix. The matrices used are derived from a family of matrices discovered by mathematics professor Jacques Salomon Hadamard at the Universi-
ty of Bordeaux, France, in 1893. Hadamard matrices give characteristic results when converted to other matrices called transposes and multiplied by their own transposes. It is this property of Hadamard matrices that allows computers to decode spectral data. Graduate student Keilee L. Liu at Michigan described the combination of a fluorescence microscope and a 256- X 256-pixel charge-coupled-device detector to form Raman spectral images (C&EN, March 19,1990, page 26). Working with Morris and graduate student Li H. Chen, he defocused a n e o d y m i u m - Y A G laser beam through the microscope lens to cover the entire sample area. This had the advantage of reducing laser energy at any one spot. The Raman-scattered light passed back through a dichroic filter, through a Hadamard mask, and impinged after focusing to a single line of coded light. In Raman spectroscopy, a small amount of excitation light is scattered from the sample. Part of the excitation light interacts with vibrational modes of sample molecules, some shifted to lower and some to higher wavelengths. The difference between wavelengths of excitation and scattered light is the Raman spectrum of the sample. The Hadamard mask is formed by photolithography of chromium on glass. A stepper motor moves the mask one slit-width at a time to yield a new pattern of slits. Lenses compress the image from each pattern along the y-axis to yield a "thick line" representing the x-axis. This passes through a spectrograph to the CCD. The CCD is "read" by moving electrical charges in each pixel to the bottom and the data Hadamard-transformed according to matrix algebra by a microcomputer. The Ann Arbor group has used the technique to image a cluster of crystals of N,N-dimethyl-p-nitroaniline according to both the symmetric N - O stretch of the nitro groups at 1310 cm' 1 and the C-N stretch of the phenyl-NH 2 bond at 1370 cm"1. They also have mapped a laminate of polystyrene and polyethylene according to the benzene C-C stretch at 1600 cm - 1 and the CH 2 wagging
Not even a
^ w cottee
'even days a week, twenty-four hours a day. For over three years, a QE automated NMR analytical spectroscopy system ran experiments at Searle Labs in Chicago with only a few hours of downtime. This sterling work record helped Searle gather high quality data from both fully automated macro and manual routine experiments. Today, two QE automated systems: • Accommodate the experiments of over 30 chemists &» Operate 24 hours a day, seven days a week • Perform both manual and fully automatic macro experiments during the day • Perform fully automatic macro programs at night and on weekends • Adapt to a demanding user schedule of 15 and 30 minute time slots
Work smarter with the new QE Plus With more speed and efficiency, the new QE Plus does the job even better—to meet your needs for automated performance day after day, year after year. For more information on the new QE Plus, write 255 Fourier Ave., Fremont, CA 94539 for a full color QE Plus brochure. Or call 800-543-5934. And get to work.
G E N MR Instruments Put us to the test. © Copyright 1990 General Electric Company 1568 CIRCLE 27 ON READER SERVICE CARD
The Last Three Generation* Your Lab Has Three Week ' O U R T E S T I N G H A S T O BE D O N E QUICKLY. A N D ACCURATELY. A N D IT H A S T O BE R I G H T THE FIRST T I M E . " — Dan Vollmer
J K V a n Vollmer is the lab ^ ^ ^ ^ ^ ^ d i r e c t o r for Waste Stream Technology in Buffalo, New York. Vollmer and his team support Waste Stream's remediation operation by performing critical point-in-time analysis on soil samples from prospective remediation projects. Old industrial sites and landfills contaminated by crude oil, coal tar, benzene, and other volatile aromatics. Waste that has been buried — and often reburied — for decades. "When we remediate a site, we don't just haul it away," Vollmer says. "We elim inate it. And the method we
use means that we just can't afford downtime. Ever." Testing is done with PerkinElmer gas chromatographs. Waste Stream performs the remediation by spraying the site with bacteria which use the contaminant as their carbon source. The bacteria "eat" the contaminant. "But some 'bugs' work better than others," Vollmer explains. "So first, we do a treatability study. We introduce different bacteria to soil samples, and test the samples at seven-day intervals for three weeks. Then we compare those data to see what kind of degradation rates we're getting. Data handling is the crux of the matter." Data handling is done with a PE Nelson data station. In a sample treated with bacteria, the c o n t a m i n a n t concentration changes constantly.
Testing complex soil samples for aromatic hydrocarbons contributes to a heavy sample schedule.
Timing is critical. You can't stop the bugs.
riave Buried The Problem* Γο Uncover The Solution. J\eliable, accurate instruments; complete data handling integra tion; unparalleled service and support; Perkin-Elmer supplies environmental labs with everything they need for everything they do. "Our test results not only have to be right," Vollmer says. "They have to be right — right now. So it's impor tant that our instruments are up and running. And that we have a quick response to any problems." The lab relies on PerkinElmer service. Chromatography, spectros copy, elemental analysis. Instruments, data handling, service. Perkin-Elmer and PE Nelson supply environmen tal chemists around the world with everything they need for everything they do. ;?;
Like the affordable and versatile Model 3100 Atomic Absorption Spectrometer equipped with flow injection; the fast and flexible ELAN 5000 Inductively Coupled PlasmaMass Spectroscopy system; the ruggedly dependable, totally integrated AutoSystem Gas Chromatograph; the revolu tionary Model 1020 Personal Integrator. Or uniquely conve nient PE XPRESS, ready to ship in-stock consumables in 24 firs.* Whatever the application, whatever the problem. From Efficient and reliable chromato graphic data handling enhances laboratory productivity.
methodologies required by the EPA to deadlines imposed by hungry bacteria. Perkin-Elmer provides solutions to environ mental problems through total integration. *u.s omy FOR LITERATURE CALL:
1-800-762-4000*
RKIN ELMER A protective suit is needed when collecting potentially toxic soil samples. Circle reader service numbers for: #12 General Information #14 AA3100 #13 AutoSystem GC #15 1020 Intearator
Perkin-Elmer Corporation, 761 Main Avenue, Norwalk, CT 06859 U.S.A. Bodenseewerk Perkin-Elmer GmbH, Postfach 10 11 64, D-7770 Ueberlingen, Federal Republic of Germany Perkin-Elmer Ltd., Maxwell Road, Beaconsfield, Bucks HP9 1QA, England
of both polystyrene and polyethyl ene backbones at 1450 cm"1. In related work, graduate student A n u r a g Govil d e s c r i b e d t h r e e dimensional imaging. Working with Morris and Li, he focused the micro scope at different levels within the sample. Then he isolated each level by subtracting images from immedi ately above and below. Vickers of Florida State outlined the importance of modulating laser energy in resonance Raman spectros copy. In this method, excitation light matches the absorption maximum of a chromophore and is reemitted in special intensity in resonance. But the intense ultraviolet light that would match the chromophores of biologically important analytes can photolyze samples, saturate ex cited states, and produce nonlinear optical effects. With pulsed lasers in
INSTRUMENTATION
i*91S particular, one that delivers 20nanosecond pulses at 20 Hz is "on" only 4 X 10"Vo of the time. Thus to generate 10 mW of average power, individual pulses must be 25-kW blasts. Working with chemistry professor Charles K. Mann and graduate stu dent Jianxong Zhu, Vickers replaced the slit in the spectrograph of a con ventional multichannel Raman spec trophotometer with a Hadamard mask. This enabled the Tallahassee
workers to defocus the laser beam over a wide area of sample, direct t h e scattered l i g h t t h r o u g h t h e mask, and collect the coded light with a 512-element diode array de tector. Thus all the laser light was used without sample damage. The mask was made by etching slit openings 0.4-mm wide in the de sired pattern in a brass strip 0.6-mm thick. There were 13 such slit or noslit elements in the pattern. Manual, sequential movement of the mask with a micrometer one slit-width at a time produced seven patterns, each seven slits wide, corresponding to the ones and zeroes of a 7 X 7 Hadamard-derived matrix. A micro computer performed the matrix al gebra needed to recover the spec trum from the sequential diode ar ray images. The Florida State chemists dem-
ln brief from the Pittsburgh Conference. Unit measures interfacial tensions dynamically A device to measure liquid-liquid interfacial tension from 0.1 to 100 dynes per cm, dynamics of interfacial tension reduction, and interfacial viscosity was described by Kevin Hool of Dow Chemical's central research engineering lab oratory, Midland, Mich. Working with Brad Schuchardt, Tim Bailey, and Suzanne Hendricks, Hool machined a steel block with an inlet tube and a cavity to a projecting tungsten carbide capillary. They immersed the block in a beaker of aqueous solution and metered an organic liquid to the capillary at 0 to 2 ml_ per hour. Interfacial tensions are inversely proportional to the cube roots of volumes of droplets that break off the capillary tip and sink (denser than water) or rise (less dense). An optical detector counts droplets, and the Midland workers calculate droplet volume according to total milliliter versus time. Titration with add ed surfactant yields critical micelle concentration. Graphs of tension versus flow rate give characteristic signatures for surfactants. Regenerable chemiluminescent sensor devised Coating electrodes with Nation resin containing immobi lized ths(2,2-bipyridyl)ruthenium(ll) [Ru(bpy)32+ for short] creates regenerable sensors that work by chemiluminescence, according to graduate student Therese M. Downey of the University of Illinois, Urbana. Working with chemis try professor Timothy A. Nieman, she determined concen trations of oxalate, amines, antibiotics, and reduced nico tinamide adenine dinucleotide (NADH) from 1 μΜ to 100 mM at 5 to 40 °C and pH 3 to 10 (pH 6 to 10 and 1 μΜ to 1 mM for NADH) in urine and blood serum as well as water. A counter electrode oxidizes Ru(bpy)32+ to Ru(bpy) 3 3+ , which the analyte reduces back to light-emitting Ru(bpy)32+. A photomultiplier tube measures light intensi ty, which is linear with analyte concentration. A silver 44
March 18, 1991 C&EN
chloride reference electrode helps the Urbana workers keep the potential above +1.1 volt for continuous regen eration of Ru(bpy)33+ High-pressure Soxhlet extractor developed A high-pressure Soxhlet extractor for liquid or supercritical fluid carbon dioxide or propane was described by chemist Kevin M. Scholsky of J&W Scientific, Folsom, Calif. The de vice may be useful to extract samples without loss of volatile components when the solvent is evaporated. Solvent vapor boils up from a still pot to a cold finger, which condenses pure solvent into an upper chamber holding a porous paper thimble with sample inside. The whole is enclosed in a steel vessel at pressures up to 1500 psi. When liquid in the upper chamber reaches a certain level, it siphons back to the still pot. A thermocouple in the upper chamber registers a tem perature drop as the chamber fills and a rise when it emp ties. The operator sees the number of cycles on a strip chart recorder. Extraction cycles of supercritical fluids result from creation and redistribution of density gradients. Copper complex resolves racemate A low-cost, easily made copper(ll)/cellulose/1,3-diaminopropane complex shows promise for analysis of mixtures of enantiomers by high-performance liquid chromatography, according to senior scientist Subramanian Muralidharan of the University of Arizona Strategic Metals Recovery Facility, Tucson. Working with graduate student Ying Tao and facility director and analytical chemistry professor Henry Freiser, Muralidharan coated the complex onto silica gel and used that as column packing. Separation efficiencies for DL-alanine were as good as or better than those of more costly or hard to make column packings. Inductively coupled plasma-atom ic emission spectroscopy showed no leaching of copper by the eluate at the 2-ppm limit of detection.
.
.
Call For Papers
.
International Symposium
T
he Organizing Committee /OP the Sixth International Symposium on Cyclodextrins Is
soliciting gapers ana posters for the symposium to he hem April 21-24,1992
T
In Chicago, Illinois, U.S.A.
his symposium will aturess current developments in basic and applied
research of the cyclodextrlns and their derivatives. The program will consist of both lecture aud poster presentations. · · · · · · · · · · · · · · · · · · ·
I
f you are interested in presenting a paper or attending the syposium
please contact us at the address below. · · · · ·
