news SECM sees double
structure of the membrane with diffusion across the membrane, they say. “[But] we’ve been able to image the topogIt has long been a goal in scanning electrochemical raphy of the pore and see [its] activity on a scale 20–50 microscopy (SECM) to “see double”—that is, to get electimes better than before,” says Unwin. trochemical and topographical information at the same time. This increased resolution allowed closer examination of In recent years, scientists have edged diffusional transport. For example, a ever closer to that mark. Now, Julie V. marked heterogeneity in the current Macpherson and Patrick R. Unwin at associated with the pores in a synthe University of Warwick have put all thetic membrane might be due the pieces together and developed a to variations in pore size. But the combined SECM and atomic force researchers did not find a correlamicroscopy (AFM) instrument, which tion between pore size and measis described in the January 15th issue ured current, so they concluded that of Analytical Chemistry (pp 276–285). the variations in current more likely The instrument is based on a comreflect variations in diffusional actimercial AFM and is equipped with a vity across the pores. special tip, which allowed both EC and Now that the instrument’s basic topographical data to be recorded. capabilities have been demonstrated, “It’s a very simple idea, really,” says Macpherson and Unwin are ready to Macpherson. “[We just] take an etched move into studies of biological sysplatinum wire . . . and insulate it with a tems. Because the instrument can special paint to make a very tiny elecimage samples in fluid, it is well suittrode area. That’s the electrochemical ed for these applications. One possisensor. Then we flatten part of the wire bility is exploring a particular kind of to make a cantilever, and that’s the membrane transport, the transdertopographical sensor.” Imaging diffusion of an electroactive species mal delivery of drugs, says Unwin. through a membrane using an SECM–AFM. In this way, the new instrument “What we’ve looked at so far is just (a) Schematic. (b) The resulting current response obtains both types of information the tip of the iceberg,” he adds. and topographical data. simultaneously but records them sepaThe researchers also want to add rately. In SECMs, on the other hand, a “noncontact” mode to the instruan electrode is scanned over a surface, ment. The tip would be scanned over and the current that flows depends on diffusion, which, in the surface initially to record the substrate’s topography. Then, turn, depends on both the distance from the surface and the with the tip retracted, the EC response would be monitored. reactivity. Thus, the two effects are difficult to separate. This approach would allow the researchers to study conductCoating sharp tips is an old trick the researchers boring and semiconducting surfaces, in addition to insulating rowed from electrochemical scanning tunneling microscopy, ones. “Clearly, there’s more work to be done . . . in terms of says Unwin. “Basically, what we’re doing is using the same methodology and applications,” Unwin says. “But we think we kind of coatings and showing that they’ll work on an AFM have taken a good step forward . . . and we’re encouraged by tip.” That was not a foregone conclusion, he adds, because what we’ve achieved so far.” Elizabeth Zubritsky the geometry of AFM tips is much more irregular. In addition to being dual-purpose, the new tips are tiny. They begin as platinum wires ~50 µm in diameter, which are GOVERNMENT AND SOCIETY etched to a very fine point. Then, the wires are coated, and Gifts for U.K. scientists as the paint cures, it retracts, exposing an area on the order of tens or hundreds of nanometers. “It’s a natural process,” After a nail-biting week for U.K. scientists, the government finally says Unwin, “that just [happens to] help us make these very small tips.” To demonstrate the combined instrument’s capability, the announced the results of its university infrastructure-funding competition researchers imaged dissolution of crystal surfaces and diffuin December 1999. Despite the delay, Christmas came early for 45 research sional transport across synthetic membranes. Both processes have previously been studied with SECM, and it has been possible to obtain some complementary topographical infor- teams around the country, who will benefit from a share of the biggest mation. However, those studies were not as revealing as researchers would have liked, Macpherson and Unwin say. handout to science infrastructure in 40 years, amounting to approximately For example, in SECM-only studies of diffusional transport, it has been difficult to observe the pores and correlate the £320 million (more than U.S. $500 million). F E B R U A R Y 1 , 2 0 0 0 / A N A LY T I C A L C H E M I S T R Y
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NELAC encounters bumpy road The fifth annual interim meeting of the National Environmental Laboratory Accreditation Conference (NELAC), held in Washington, DC, in December 1999, got off to a grim start when Henry Longest of EPA’s Office of Research and Development (ORD) announced that the program should become self-sustaining. Although EPA will continue to be a partner, funding responsibilities for NELAC must be met by the private sector, he said. The announcement comes after yet another reorganization within EPA. In October 1999, EPA created a new information office, under which it placed its quality assurance division. Although some believe that NELAC should reside with the quality assurance division, the decision was made to keep NELAC under ORD. Many within ORD believe that its money would be better spent on research than on a national laboratory accreditation program. The NELAC board of directors, however, is optimistic that EPA will continue to fund the program. “We have a commitment from EPA’s deputy administrator to fund NELAC until 2001,” says past NELAC chair Ken Jackson. Nonetheless, NELAC’s Transition Committee has been charged with quickly convincing EPA to continue its funding beyond 2001 or finding alternative monetary sources. NELAC is a nationwide effort to reduce the number of accreditations required for environmental laboratories to conduct business across state lines (Anal. Chem. 1999, 71, 329 A–331 A). After five years of developing standards,
Among the projects to be supported to the
implementation of the program officially began the summer of 1999 following the fifth annual NELAC meeting in Saratoga Springs, NY. To be successful, there cannot be any inconsistencies between EPA regulations and the NELAC standards. A strong partnership must exist between NELAC and EPA. Evidence that this partnership is lacking, however, became apparent on December 1 when EPA’s Office of Water (OW) promulgated a regulation (Fed. Regist. 1999, 64 (230), 67449–67467) that is clearly inconsistent with the NELAC Proficiency Testing (PT) standards. When the regulation was in its proposal stage, NELAC’s PT Committee sent in comments pointing out its inconsistencies with the NELAC standards, says Barbara Burmeister, committee chair. However, EPA promulgated the regulation anyway, disregarding NELAC’s comments. According to Jackson, the NELAC board of directors met with Cynthia Dougherty of OW to express concerns with the new regulation and to prevent such inconsistencies from arising in the future. Despite the bumps encountered, implementation of the program is moving forward, say NELAC officers. Eleven accrediting authorities have been approved and ~1300 environmental laboratories are expected to be NELAPaccredited in June 2000. “We are no longer predicting what could happen; we are dealing with real issues as they occur,” says NELAC chair Jim Pearson. As Paul Kimsey, a member of NELAC’s board of directors put it, “NELAC has gone live.” Britt Erickson
working in almost any area of research could
center will study air–sea exchange between the
tune of £750,000–30 million are pollution moni-
apply for funding with proposals subject to
atmosphere and the ocean surface. The focus
toring, oceanics and the environment, atmos-
peer review. Many worthy teams inevitably
will be on the effects of greenhouse gases,
pheric chemistry, protein interaction studies,
lost out despite the size of the handout. But
aerosol formation, and ozone cycling. Teams led
and combinatorial chemistry, as well as asso-
the money provides the much needed cash
by Tim Jickells and Karen Heywood at the cen-
ciated analytical science.
injection for buildings, major equipment, and
ter will be among the recipients of funding.
The funding comes as part of the Joint
other elements of university research infra-
Infrastructure Fund, a financial package sup-
structure. The share of the cash provided by
enthuses Jickells. “It will represent a huge
ported by the Wellcome Trust and the govern-
the Wellcome Trust is specifically bound for
investment and allow us to make great
ment (through its various research councils),
biomedical and related research facilities.
progress in our understanding of the interac-
with an additional share from the Higher Education Funding Council for England. Scientists 102 A
A new laboratory at the University of East Anglia will be among the major recipients. The
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“The JIF funding is extremely exciting,”
tions between the global atmosphere and oceans. Our aim is to take exciting develop-
news ANDI MS standard finalized ments in analytical chemistry and apply them in the environment. So the money will be spent mainly on instrumentation, including a range of new mass spectrometers, such as proton- transfer chemical ionization mass spectrometers, which have recently been developed.” He adds that his group will be one of the first to take these machines into the field to study environmental climatic processes. The team will also be acquiring an electrodynamic single-particle balance and coupling it to a new Raman spectrometer to investigate the processes occurring on individual aerosol particles at high ionic strengths. Mark Bradley heads one of the leading teams in the field of combinatorial chemistry at Southampton University. His group is one of the successful bidders for funding from JIF. They work on various aspects of combinatorial chemistry, including the development of novel “safety-catch” linkers for solid-phase synthesis and the analytical techniques essential to the identification and screening of products. Michael Dexter, director of the Wellcome Trust, says the funding will allow the U.K.’s scientific community to attract and retain the best scientists and to make it increasingly competitive. Scientists will flourish in the best facilities, he adds. Ironically, the announcement of funding to vastly improve science facilities in the U.K. comes just weeks after the government backed down on its controversial decision to refuse planning permission to the Wellcome Trust for its own infrastructure expansions at its “Genome Campus” in Hinxton, near Cambridge. David Bradley
After several setbacks, the Analytical Data Interchange (ANDI) protocol for standardizing MS data has been finalized by a subcommittee of the American Society for Testing and Materials (ASTM). A similar protocol for chromatography was approved in September 1998 (Anal. Chem. 1998, 70, 447 A–448 A; 1999, 71, 90 A). According to Lynn Matthews, chair of the ANDI subcommittee, both the chromatography and MS standards have now been successfully transferred from the Analytical Instrument Association (AIA) (now called the Analytical and Life Sciences Systems Association) to ASTM. ANDI, which began under the auspices of AIA, is an effort to standardize software for analytical instruments so that data files generated on one manufacturer’s system can be read by another manufacturer’s system. The responsibility for developing ANDI protocols was transferred from AIA to ASTM in 1997 (Anal. Chem. 1997, 69, 455 A; 589 A). Some believe that because the MS standard took so long to be approved, it is no longer of much importance to the analytical instrument manufacturers. “MS/MS data and MALDI are not even addressed in the standard,” says O. David Sparkman, an MS consultant who has been actively involved in the ANDI efforts. According to Matthews, however, the existing MS standard serves only as a baseline. “The next step is to revise the standard,” she says. The ANDI subcommittee has even looked into the feasibility of combining the chromatography and MS standards into one standard, she says. Whether the two standards are merged depends on what the market wants, says Matthews.
And that is the next phase for ANDI—determining what the end-users want. “We are going to be distributing questionnaires to the market. Up until now, the efforts have been mostly the analytical instrument vendors trying to agree on the standards.” Now, it’s time to listen to the other side, she says. The market has been using the ANDI standards for purposes other than for what they were developed. “ANDI protocols were developed to be able to take data from one manufacturer’s system to another’s and still be able to read it,” says Matthews. It turns out that “customers have been converting files to ANDI protocols so that they can store the data for long periods of time and have the confidence that whenever they need to retrieve the data, they can read it,” she explains. Because manufacturers revise their software on a regular basis, the ANDI subcommittee is considering round-robin testing of the standards on an annual basis. The first chromatography round-robin test is complete, and, according to Matthews, a round-robin test for the recently approved MS standard is expected to take place in the second quarter of 2000. “[But first], we need to get financing for this effort,” she says. The ANDI subcommittee has approached some of the major analytical instrument manufacturers for funding, but only a few have agreed to contribute to the treasury, which will be managed by ASTM. Sparkman has agreed to coordinate the round-robin testing of the MS standard. Matthews emphasizes that the ANDI protocols should be driven by the market, not the instrument companies. Anyone interested in participating should contact her at
[email protected]. Britt Erickson
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