Artful teaching
peer and faculty reviews of each part of the multisection paper during the October to December period," says Merritt. Taking advantage of an extensive art colIn addition, the lab emphasizes teamlection on campus, Wellesley College anawork. "I have facilitating conferences with lytical chemistry professor Margaret Merstudents," says Merritt. "We get all the ritt is developing a course in which stu[students researching] blue pigments todents propose analytical methods to gether, for example." Students also consult examine pigments on real art objects. The course combines art history and chemistry, with Katz, who is an expert on pigments. and includes talks from art conservators. Merritt admits that she would like an "I've never had students so enthusiastic experimental component to the course. She about analytical chemistry," says Merritt. has redesigned die course this year so that physical chemistry is a prerequisite. This Merritt teaches the class in collaboration will provide her students with the backwith Melissa Katz, assistant curator at the Davis Museum and Cultural Center at Welles- ground to do reflectance IR measurements on selected sections of art objects with blue ley. Students in the class are assigned a parpigments. "There is not much in die literaticular color pigment—yellow, for example. ture [on IR reflectance spectra of pigments] The color is linked to pieces in the museum and we hope to contribute to the literature." collection; for example, the yellow is found in a 13th-century stained glass. Students are expected to investigate the chemistry of the Your job is this color, identify likely compounds responsible for the color, and propose a "wet" and an course instrumental method of analysis. "The lab Students taking instrumental analysis at the extends the [course] material beyond the University of Kansas spend part of their first textbook to techniques such asXRF [X-ray day in this course "applying" to work at one of fluorescence] " says Nlerritt several hypothetical jobs requiring analytical The students learn how to research a problem by investigating the chemistry of the pigment, how to sample non-destructively, and how to deal with heterogeneous samples (many pigments are covered with a varnish, for example). The work begins in mid-October and is completed in mid-December when students turn in a paper describing their results. "There are continual
services. Fifteen weeks later, the students will describe—in oral and written presentations— the experimental procedures they have developed to solve their "company's" problem, their results and data interpretation, and the monetary costs they have incurred. "We have sacrificed comprehensive treatment of various instrumental methods in favor of students concentrating on perhaps one to three techniques
that they will learn thoroughly," says George Wilson, who, along with Craig Lunte, created the course. Students select tiieir jobs from such options as environmental sampling at a Superfund site (which involves real samples from sites near Galena, KS), providing pharmacological data on the excipient 2-amino-2-hydroxymethyl 1,3-propanediol orTRIS (requiring animal studies and urine collection), and determining the source of "skunkiness" in a microbrewery beer. Students in each company are expected to work together; in fact, die team is expected to meet weekly, and half of each student's course grade is based on the group's performance. After an initial four-week introduction to the analytical equipment, students are given priority access to a broad range of sophisticated, research-grade instrumentation for their analyses, which range from a GC/MS system, to FT-IR and Raman spectrometers, to a scanning probe microscope. Biweekly reports of progress are given to Wilson, who, along with the teaching assistants, assumes the role of middle management. Students in some projects also work with an outside consultant. According to Wilson, students not only learn about analytical chemistry, but gain an appreciation of the role of government regulations, the actual costs of analyses, and the nature of group dynamics. "The objective is to learn analytical chemistry, but also to experience all dimensions of problem solving," says Wilson.
NEWS FROM THE FIFTH INTERNATIONAL SYSPOSIUM ON CE David Bradley reports from York, England.
Glow with the flow Norman Dovichi and his team at the University of Alberta (Canada) have developed a capillary electrophoresis (CE) system tiiat can analyze all the wells in a 96-well microliter plate simultaneously. According to Dovichi, it could help speed up DNA sequencing, protein analysis, and the screening of protease inhibitors. Dovichi described the instrument as a two-dimensional array of 96 capillaries held in a sheath-flow cuvette. At one end, die capillary bundle is splayed so tiiat each capillary mates with an individual well on the plate. The sheath-flow cuvette serves as a chamber for postcolumn detection by laser-induced fluorescence, excited by an argon ion laser at 488 or 514.5 nm.
According to Dovichi, this differs from tested with dye-labeled protein samples septhe conventional approach in which the arated initially by capillary gel electrophorecapillaries themselves act as detection sis. The device has potential for highchambers. His instrument instead detects throuehnut screening. "This instrument can fluorescence from the analytes after they have exited the capillary. The fluorescence is collected and collimated with a single camera lens, dispersed spectrally using a large prism, and re-imaged on a high-efficiency CCD (charge-coupled device) camera feeding into a computer. "We generate 96 fluorescence spectra simultaneously, one from each capillary," said Dovichi, "forming an 8 x 12 array that fills the CCD array." The instrument has been used primarily for analyzing DNA sequencing plates, collecting information about die Schematic of a single-capillary version of the fraction in each well, but it has also been iheath-flow cuvette CE detection strategy. Analytical Chemistry News & Features, October 1, 1998 6 4 1 A
News
analyze 96 samples in the time it takes for a single-capillary instrument to analyze one sample," explained Dovichi. "There are obvious applications in the pharmaceutical industry for screening the large libraries generated by combinatorial chemistry." Dovichi's team has already developed an assay for proteases, which he says could, in principle, be used for large-scale screening of protease inhibitors. A patent has been issued on the device in the United States.
Strategic separations Jean Louis Viovy of the Physical Chemistry Laboratory at the Curie Institute (France) and his colleagues are designing strategies to separate large molecules and particles in capillaries.
PEOPLE
Alan Walsh 1916-1998 Sir Alan Walsh died on August 3. Walsh was known for his contributions to die field of atomic absorption spectroscopy (AAS). Modern flame AA instruments differ very little from his original concept. Atomic absorption, and its more recent allied techniques, have completely changed metal analysis in commerce, in environmental protection, and in clinical and biological situations. Certainly Alan Walsh contributed much to this revolution. Walsh was born in Lancashire, England, in 1916. He graduated from Manchester University with a major in physics and in 1939 started work at the British NonFerrous Metals Association, developing and using emission spectrochemical analytical methods. In 1946, he moved to Australia to join what would soon be called CSIRO (Commonwealth Scientific Industrial and Research Organisation). Walsh formed a spectroscopy group within the chemical physics section of the industrial chemistry division and quickly made substantial contributions to IR instrumentation. The idea for AA spectroscopy came to him one Sunday in March 1952, while working in his garden. It occurred to him that the absorption of light by atoms, al642 A
Until recently, he said, progress in CE was mainly due to its performance in small ion and molecule separations, although intermediate-sized species, such as proteins and nucleic acids up to about one kilobase (kB) have also been tackled successfully. He pointed out that the success of CE in separating medium-sized nucleic acids boils down to the use of neutral polymer additives, which act as a sieve. However, attempts to separate larger species have been hindered by so-called electrohydrodynamic collective motions in the carrying agent due to inhomogeneous ion transport leading to a polarization of the fluid. In other words, fluid mixing leads to spurious peaks and loss of resolution. "The phenomenon could only be avoided [up to now] by reducing field strength, which leads to impractically long separation times" he said.
ready so important for many years to astronomical physicists, should be a useful alternative to the emission of atoms for chemical analysts. By 1955, he published his first paper in this field. The equipment and technology for flame AA were almost identical to that still being manufactured and used today. But Walsh was much more than an insightful inventor. The early work in his lab successfully provided the technology for lamps, not then commercially available, and for flame burners, because none of those then commercially available worked well for AA. He understood clearly the instrumental requirements, although some of the instrument companies first entering the field failed to heed his advice. Walsh received many honors and awards during his career. In 1977, he was made a Knight Bachelor (Sir Alan) by the Queen of England. He was elected a Fellow of the Royal Society (England) and a foreign member of the Royal Swedish Academy of Sciences. He received the medal of the Royal Society, the Talanta Gold Medal, the Hasler Award of the Society for Applied Spectroscopy, and the first CSI Award in Analytical Spectroscopy. Walsh brought to inorganic analysis great enthusiasm, a way of working with analysts and witii licensees of the CSIRO patents that was persuasive and compelling. He was always unpretentious, always full of clever and innovative ideas. It was a real pleasure to be in his company. Atomic spectroscopy has lost a great man. Walter Slavin
Analytical Chemistry News & Features, October 1, 1998
Viovy and his team hope to tackle the problem using the idea that, rather than a simple polymer acting as carrier, the instabilities in the fluid might be greatly reduced by adding a zwitterionic buffer. The carrier ions are then in fast chemical equilibrium with a large excess of neutral species, so polarization is counteracted by the law of mass action, which tends to restore uniform carrier density at the expense of the neutral form. The buffer makes the system more homogeneous and so removes the source of the instabilities. Using the buffer technique, Viovy's group has separated 100-kB nucleic acids. The idea is still quite new, and he admitted that additional efforts are needed to live up to the expectations of the biologists who would like to be able to separate 200-300 kB nucleic acids with CE.
GOVERNMENT AND SOCIETY
Environmental analysis collaborative starts up Environmental analytical chemists and Oiose who use their data are invited to join a collaborative effort to share knowledge. The International Collaboration for Environmental Analytical Education (ICEAE) is a free service sponsored by the Waste Policy Institute (Blacksburg, VA). According to Larry Keitii, vice president and senior corporate fellow in the Institute, ICEAE will include a database of analytical measurements in all types of media. As currently envisioned. ICEAE will promote international and local collaborations list new sources of funding disseminate information on methods and instrumentation collect analytical data demonstrate aoproaches for samrjlini? and ciuantitative analysis organize short courses provide a means for creating collaborative Droposals for grants and con'lid in improvint* environmental curricula and establish a network for sahh-iticals and smdinte-level education For more information or to ioin contact Keith hv fay Pvtftfifi? RW1) or h > mil flarrv U 'it & ' t
