contents
http://pubs.acs.org/ac ISSN 0003-2700
February 1, 2001 / Vol. 73, No. 3
features 74 A
COVER STORY
Detecting DNA Hybridization and Damage. Efforts to develop electrochemical transducer-based devices that determine nucleotide sequences and measure DNA damage are beginning to bear fruit. These devices promise low costs, simple designs, small dimensions, and low power requirements. Emil Palec˘ ek and Miroslav Fojta of the Academy of Sciences of the Czech Republic review the present state of DNA electrochemical analysis, focusing on electrochemical detectors that use DNA as a recognition layer.
DNA detectors. 74 A
84 A
The Water Project. A meeting of Trout Unlimited—an organization dedicated to trout and salmon habitat conservation—became the inspiration for restructuring the undergraduate analysis class at Union College. T. C. Werner, Peter Tobiessen, and Karen Lou describe a “real-world” laboratory in which students collect data to help Trout Unlimited plan their stream-stocking activities.
88 A
Tracing the History of Selective Ion Sensors. The discovery that synthetic membranes can be tailored to choose and transport ions with a selected charge sign or a particular charge has led to exciting opportunities for theory and experiments. Richard Buck from the University of North Carolina and Ernö Lindner of the University of Memphis present their view of how membrane-separated cell research developed into ion-selective electrodes.
news 64 A
Analytical Currents Bar codes for combinatorial libraries. Zeroing in on cellular zinc. Aggregating K+ sensor. Sweet new saccharide sensor. IMS combines with FT-ICR.
68 A
Research Profile MALDI chip shot. Protein analysis gets a “spot-on-a-chip”.
70 A
Lab Profile Collaboration pays off for NCSR. The National Centre for Sensor Research enjoys good luck in Ireland.
Automated MALDI-TOF
Spots on chip. 68 A
50 A
A N A LY T I C A L C H E M I S T R Y / F E B R U A R Y 1 , 2 0 0 1
contents
72 A
Government and Society British polymer scientists get enhanced service.
departments 53 A
Editorial The Postdoc: An Opportunity for Learning and More. Today’s postdocs occupy vital roles in the research laboratories of analytical chemistry and science in general.
55 A
Letter to the Editor Death, Taxes, and Analytical Chemistry.
57 A
In AC Research
99 A
Product Review Top of the line MS. FT-ion cyclotron resonance MS is finding applications in areas where high resolution and exacting structural determination are required.
103 A
Meetings Pittcon 2001
Water project. 84 A
History of ISEs. 88 A
111 A
New Products
1C
AC Research Contents
393–723
AC Research
724
Author Index
Bar codes for combinatorial libraries. 64 A
FT-MS. 99 A
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A N A LY T I C A L C H E M I S T R Y / F E B R U A R Y 1 , 2 0 0 1
editorial
The Postdoc: An Opportunity for Learning and More T
he concept of an apprenticeship of advanced study following completion of the Ph.D. is over a century old. This apprenticeship is an implicit acknowledgment that most young men and women cannot learn enough about their fields during the Ph.D. period to be successful, independent, cutting-edge researchers. The primary purpose of a postdoctoral appointment is to continue the education of the “postdoc”. The postdoc has the responsibility to recognize that the time is a learning opportunity, not just a temporary job. The postdoc’s mentor—80% of whom are academic faculty—has the heavy responsibility to provide a challenging yet supportive environment, and to select research experiences that expand the postdoc’s existing Ph.D. skills and knowledge. Postdoctoral experiences are important stepping-stones for employment in all sectors—industrial, government, and especially academic. Supervisors must accordingly recognize that apprentices need to hone their original, independent ideas, and perhaps be pushed into directions that make them more than clones of their Ph.D. and postdoctoral advisers. Learning is meant to be fun, but it needs an edge of adventure and should follow “steep roads and swift streams”. The postdoctoral appointment is, however, much more than an educational process. Today’s postdocs occupy vital roles in the research laboratories of analytical chemistry and science at large. As an apprentice, the postdoc assumes, in a junior way, all of the roles of a mentor, conceiving research directions as well as pursuing them, helping in the training of others, writing research papers, and presenting talks at conferences. The number of postdocs in the United States alone is large, having steadily grown since the 1970s and doubling since 1981 to an estimated 52,000 in all fields in 1998. About 40,000 of these postdocs received their Ph.Ds from U.S. institutions, and about 80% work in academic institutions. The overwhelming portion (>70%) of the 40,000 are in the life sciences. Chemistry is a much smaller portion (~9%), but the 3700 holding chemistry appointments are a significant part of our research force. In chemical laboratories, there is about one postdoc for every four full-time graduate students. The proportion in life sciences is even larger: 1 in 3. Furthermore, nearly one-half of the postdocs in the United
States are not U.S. citizens. Nevertheless, a large fraction of them find employment in the United States following their postdoctoral experience. The United States has always been a nation of immigrants, and postdoc immigrants add to our national intellectual wealth in a positive and significant way, a fact recently recognized by a liberalization of visa regulations. Fueled by stories of individuals recycling for years through multiple postdoc positions, several recent articles have described an “over-supply” of postdocs in the United States. Unfortunately, generalizations are made that ignore sharp differences between disciplines. In 1998, the average period a postdoc worked in the biological sciences exceeded 4 years, and the extant pool of postdocs amounted to >2.5 years worth of Ph.D. production. The largesse of funding agencies for the life sciences has indeed led to a surplus of hopeful faculty candidates relative to the (primarily academic) employment market. On the other hand, the statistics in chemistry are much more reasonable: In 1998, the average postdoctoral stay was slightly over 2 years for a much smaller reservoir of postdocs. This corresponds to about 1.5 years for the ~2300 chemistry degrees produced in 1998. The potential for an economic downturn swelling chemistry’s postdoc ranks remains, and in fact, such an event (as it did in the 1970s and early 1990s) usefully serves as an unemployment buffer for fresh degree recipients. The postdoctoral position has many facets. I believe it is an extremely beneficial system and, as it has become more and more the “cloth” and “fiber” of modern science, deserves institutional recognition to maintain its quality. That is the thrust of a recent National Academy Press publication (http://www. nap.edu/catalog/9831.html), which provided the data for this editorial.
F E B R U A R Y 1 , 2 0 0 1 / A N A LY T I C A L C H E M I S T R Y
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EDITOR Royce W. Murray University of North Carolina
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Iowa State University/Ames Laboratory
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ThermoQuest/Finnigan
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letter to the editor
Death, Taxes, and Analytical Chemistry I
found Jeanne Pemberton’s March 1, 2000, (p 173 A) editorial thought provoking. Here are my thoughts. Analytical chemistry’s disconnect between teaching and the way the field is actually practiced is not unique. For example, it is convenient to organize book chapters by topics such as MS, chromatography, electrochemistry, etc. Inorganic professors discuss transition metals one week and inert gases the next; biochemists have their chapters on amino acids, nucleotides, and phospholipids. Isn’t the purpose of all this to organize information so it can be readily at hand when the real work begins? The variety implied by the “problem solving approach” to teaching advocated by Pemberton would be virtually infinite. I can imagine textbook chapters with titles such as “What smells so bad at the pilot plant?” or “Let’s develop a new drug for HIV”. Instead, we have organized analytical chemistry techniques to clarify its presentation. This makes sense. Perhaps, the issue Pemberton addresses is best handled by admitting up front what we are doing. Students should recognize that analytical tools are only useful when selected to address a particular problem. Many textbooks suffer because they don’t teach students how to select one tool over others. However, I do agree with Pemberton that the “process” of making analytical measurements is far too involved to be covered as a side issue in inorganic or organic classes. There simply isn’t enough time in these courses. Most chemists (and many biologists, physicists, and engineers) need analytical chemistry and practice it to some degree. The same groups use inorganic, organic, and biochemistry as well. There is no movement to suggest that organic chemistry is unimportant because analytical chemists use it— why would the reverse be true? The term “multidisciplinary” was probably invented in the 1960s when subjects began to blend. Such an invention would have amused 19th century natural philosophers, who blended many disciplines and saw no harm in their practical application. The problem solving approach to teaching analytical chemistry has merit, especially in the lab. It fosters teamwork and uses the literature to help students make choices between methodologies. Nevertheless, how can we expect this notion to have widespread appeal when the majority of papers published in
Analytical Chemistry do not take a similar approach? Many address the determination of some substance, such as a fluorescent dye, that has no relevance to either a natural science or a commercial need. Nevertheless, demonstrating the feasibility of a novel concept has merit, but value judgments on the application are not made or are not welcome. Likewise, organic chemists regularly “make things” of no immediate value to society. Frequently, “the process” (the reagent) used is innovative and has consequences far beyond any immediate publication. Kimberly Prather argues in the August editorial (p 501 A) in favor of “real-world” measurements, which are far more impressive. Long ago, I gave a talk with the title “Why determine a drug in distilled water when urine is cheaper?” My point is similar to hers. The importance of analytical chemistry is not arguable. Three things in life are certain: death, taxes, and the need for analytical chemistry. Quality measurements are hard to come by when we are pressed for time. If analytical chemistry were to leave the curriculum, it would quickly return. Reports of its demise are both frequent and wrong. Sadly, some of these reports come from analytical chemists. Yet, I’ve never noticed any problem for academic analytical chemists who do something with their inventions. In his April 1 editorial (p 245 A), Renato Zenobi suggests that some would be discouraged by the notion that “analytical chemistry is only a service.” Only? That is a very high compliment indeed. Medicine, law, accounting, brewing beer, being a mother or father are all services. What’s wrong with being a service? I do agree with Zenobi that more than a few analytical chemists have inferiority complexes that are unwarranted. His call for confidence and pride is most welcome and needed. Our discipline contributes mightily to what we know about our universe and has improved healthcare, water quality, food safety, and so many other areas. It’s clear that analytical chemistry is damned important no matter who practices it, and the more the better. Peter T. Kissinger Purdue University and Bioanalytical Systems, Inc.
[email protected] F E B R U A R Y 1 , 2 0 0 1 / A N A LY T I C A L C H E M I S T R Y
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