contents
http://pubs.acs.org/ac ISSN 0003-2700
April 1, 2002 / Vol. 74, No. 7
features 190 A
The Forensic Community’s Response to September 11. When the search and rescue mission became recovery operations in New York, Washington, D.C, and Somerset County, Pa., the forensic specialists took charge. Wilder Damian Smith discovers how forensic laboratories are dealing with unprecedented numbers of DNA analyses.
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Stretching the Wire Frontier. Tiny metallic and semiconducting wires and nanotubes are being explored as sensing devices. Judith Handley investigates the unique principles that account for the anomalous behavior of some of these devices.
Picturing 2-D flow. 208 A
200 A
A Critical Appraisal of Capillary Electrochromatography. Take the best aspects of CE and capillary HPLC and put them together to separate charged analytes—it’s called capillary electrochromatography. However, researchers Klaus Unger, Marion Huber, Karin Walhagen, Tom Hennessey, and Milton Hearn from Johannes Gutenberg-Universität (Germany), Ferring AB (Sweden), and Monash University (Australia) find there are lots of technical questions to answer when creating a new technology, especially for bioscience applications.
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Flow of Multiple Fluids in a Small Dimension. Professors look for ways to illustrate chemistry beyond chalk drawings, and students love to see demonstrations. Purnendu “Sandy” Dasgupta, Kazimierz Surowiec, and Jordan Berg at Texas Tech University found a cheap, simple, and aesthetic way to please both sides. Their intertwined patterns illustrate the principles of 2-D flow and chemical interaction, which are the crux of microfluidic chip technology.
COVER STORY
news (a)
(b)
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CH3
How low can a protein go? 185 A
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AnalyticalCurrents MS rises to yeast challenge. a The chiral square grid. a Beefing up topdown. a Nanotube problem now soluble. a New tricks for molecular beacons. a Molecules go with magnetic flow. a Less noise for MALDI spectra. a “Magic” NMR locates protein. a Mass spectrometer is a space “Dustbuster”. a Fluorescence polarization tracks ligands. a CE tackles DNA adducts.
contents
CE + cap-HPLC = CEC. 200 A
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Research Profiles The unexpected gas-phase Raman spectrometer. Although distressing, loose valves can be a blessing. a SERRS sensitivity gains with shrinking flow. Microfluidic flow cells permit quantitative analysis.
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Governm entand Society Translating trans fatty acid labeling.
Record numbers of forensic DNA.
departments
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Editorial Our Tangled Bases of Knowledge. It is easy to point to the importance of a knowledge base, but not so easy to understand its origins.
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In AC Research
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ProductReview SEMS in the PC Era. Elizabeth Zubritsky explains the value of abandoning knobs in favor of a PC.
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AC Educator International Meeting Examines Analytical Curricula. Gary Christian at the University of Washington learned how the Europeans prepare novice and veteran analytical chemists for a world economy that is increasingly dependent on analytical chemistry.
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Books and Softw are Design, Analyze, and Optimize with Design-Expert. Katherine Alben at the New York State Department of Health reviews the software package Design-Expert 6.0.6.
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M eetings
1C
AC Research Contents
1477–1743
AC Research
1744
AuthorIndex
Are you wired? 196 A
Goodbye clunky knobs … 215 A
A P R I L 1 , 2 0 0 2 / A N A LY T I C A L C H E M I S T R Y
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e d i to ri a l
Our Tangled Bases of Knowledge T
he achievements of modern analytical chemistry are numerous. The community can be justly proud of how well it can measure ultrasmall quantities of chemicals in microscopic spaces, separate complex mixtures, and image spatially distributed chemicals. These achievements rest on a knowledge base derived from past achievements. Analytical (and other) chemists who pioneer new measurement approaches can exploit past achievements, especially if they appreciate the strengths and limitations of these earlier works. Sometimes, researchers never learn that prior knowledge exists, and rediscover it. Either way, the soundness of the work is pivotal to advancing our capacity for measurements. It is easy to point to the importance of a knowledge base but not so easy to understand its origins, because they are usually a tangle of decades-long threads of intersecting investigations and applications. To illustrate, the current active field of designing analytical arrays for drug discovery and other purposes requires patterning of chemicals. One approach to such patterning, soft lithography, relies, in part, on making ordered molecular monolayers that are free from pinhole defects, namely self-assembled monolayers (SAMs) of organic thiolates chemisorbed to gold surfaces. The earliest reports of SAMs were decades earlier, describing long-chain alkanesilanes bound to glass surfaces. To learn how to best make these alkanesilane SAMS, it was important to characterize their molecular ordering, which became very detailed with the use of grazing-angle FTIR with polarized beams. The FTIR experiment, in turn, was a product of a long evolution of vibrational spectroscopic instrumentation, which was spurred in the first half of the 20th century by the petroleum industry’s need to dissect the composition of petroleum fractions. Before organosilane SAMs came onto the scene, researchers introduced chemically designed adhesive reagents in the form of nonorganized monolayers and thin films of organosilanes bonded to surfaces—a chemistry that is still in use. Binding organosilanes to surfaces was introduced into gas and liquid chromatography as bonded phases, a potent application that also remains in use. Moreover, organosilanes bound to conducting oxide surfaces were used to construct some of the earliest
chemically modified electrodes. Yet another thread involving the current study of thiolate binding to gold surfaces can be found in schemes for molecular electronic devices. I have covered only a fraction of the knots and intersections of the above tangle. There is not enough space here to continue, but already I have managed to cover a wide swath of analytical chemistry by considering the knowledge base of analytical arrays. It has been said that chemists are poor historians and lack interest in their past. The history of an individual human, if thoroughly recounted, is not solely that of his or her acts, but also of how he or she is influenced by other individuals, who, in turn, were influenced by yet others. The chemical history of a given topic has analogous second-order effects; although the literature documents the development of science, the influences of knowledgeable colleagues on investigators can be subtle and hard to discern. But I suspect that we are poor historians because it is more fun to make future history than to study the past—chemists create things after all. In addition, scientific granting agencies don’t usually make it their business to support the efforts of a historian. Nonetheless, understanding knowledge bases can be important to research and development chemists, notably by helping them avoid wasted effort in pursuing “blind alleys” and “reinventing the wheel”, and helping them spot holes and limitations in old work, which brings insights to new research efforts. More importantly, scholars who understand the source of their knowledge base can do invaluable service by educating federal and state granting agencies about the numerous unforeseen benefits of past research investments. I also believe that stories about the history of analytical chemistry knowledge bases can be an inspiration to our students, because they provide many examples of how an individual’s efforts can make a difference in science over a long time.
A P R I L 1 , 2 0 0 2 / A N A LY T I C A L C H E M I S T R Y
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