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poor dissociation or larger molecular ions. Quantification of both inorgan- ic mineral nutrients and biologically active eicosanoids was achieved by using stable isotope dilution in the FAB and gas chromatography (GC)-MS modes, respectively. An overview of the use of GC-MS tech- niques in ultratrace analyses of envi- ronmental contaminants in air and in marine sediments included descrip-

tions of GC-MS and LC-MS sys- tems with improved sensitivity and versatility in environmental analy- ses.

R. SELF

Dr. R. Self is employed by the Agricultu- ral and Food Research Council, AFRC Institute of Food Research, Norwich Lab- oratory, Colney Lane, Norwich NR4 7UA, U.K.

Affinity chromatography and interactions

A report on the Seventh Interna- tional Symposium on Affinity Chromatography and Macromo- lecular Interactions, held in Oberammergau, F.R.G., 17-21 August 1987.

This symposium, held every two years, was organized in 1987 by H. P. Jennissen (Munich, F.R.G.) and W. Muller (Darmstadt, F.R.G.) and took place in Oberammergau, a charming town in the Bavarian Alps. The meeting attracted about 250 par- ticipants and 40 invited speakers pre- sented new, significant devel- opments in the broad area of affinity chromatography as well as helpful in- sights into related fields. The lec- tures that fall into the latter category were chosen to provide the numer- ous users of affinity chromatography in research and industry with easier access to the fundamental processes involved in their daily work. The ma- jority of these presentations dealt with association and dissociation reactions of macromolecules - mostly biopolymers - in solution, as well as their interactions with solid surfaces. The aspect of recognition necessarily formed a central point for discussion in the more theoretical part of the scientific program.

More than 80 posters drew atten- tion to developments at the forefront of research in affinity chroma- tography. Recognition between pro-

macromolecular

teins was presented in a very con- vincing way by Huber, on the basis of X-ray data. Sterical changes in side- chain and larger segment positions based on inherent protein flexibili- ties were observed in most protein- protein complexes studied and seem to form a general step in protein- protein recognition and enzymatic processes. Local rigidities are ob- served when diffusional motions of catalytic intermediates would be un- favourable or photo-excited states have to be conserved.

In nucleic acid-protein recogni- tion, as treated in the example of DNA-cap protein interaction by Crothers, structural changes are sim- ilarly involved. In this example, the DNA binding site undergoes bend- ing by more than 90” upon inter- acting with the protein. Several very interesting presentations dealt with the interaction of dissolved polymers with solid surfaces. Most of the mod- els developed used loop structures of the bound polymers in which some loops interact with the solid surface, while others stick in the surrounding solution. Such treatment necessarily involves cooperative and anti-co- operative binding processes exhibit- ing corresponding effects in the ki- netics of association and dissocia- tion.

In the area of applications of solid phase recognition processes, the contribution of Ugelstad was partic- ularly noteworthy. He reported the

trendr in analytical chemistry, vol. 7, no. !,I988

use of magnetic, highly monodis- perse polymer beads coated with an- tibodies to remove tumor cells from the blood stream with the help of magnetic barriers. At the end of his lecture he anticipated the obvious question about how to make the monodisperse polymer beads (the well-known MonoBeadsTM) by rush- ing through a whole page of differ- ential equations describing the poly- merization kinetics - no doubt showing how simple the answer is!

Wilchek received this year’s Pierce Award for his pionier work in affinity techniques, which he began working on about 20 years ago using the biotin-avidin interaction. In his Pierce lecture he reviewed his work under the, title ‘My life with affinity’ in his well-known humorous style. He also presented a study on an un- desirable side reaction involved in the preparation of affinity carriers activated by N-hydroxysuccinimide, which yields an unstable binding of the affinity ligand. Following his own personal motto: ‘If an experiment does not go the way you expect, God is smiling on you!’ he not only identi- fied the origin of this side reaction but also showed how to avoid it.

Of the lectures on liquid phase af- finity techniques, the contribution of Brooks describing the separation of cells by affinity partitioning in Al- bertsson’s aqueous two-phase poly- mer systems (based on PEG and dex- tran) broadened the scope of the meeting. The application of the same systems in liquid-liquid partition chromatography of proteins and nu- cleic acids was presented by Muller who showed how to solve the basic problem with this type of chroma- tography, i.e. the selective fixation of one of the two aqueous phases to a support in order to obtain a station- ary liquid phase, making use of the classical concept of polymer incom- patibility.

The arsenal of classical affinity chromatography methods was en- larged by a new affinity group devel- oped by Porath and co-workers in Uppsala. This group, acting on the basis of ‘thiophilic adsorption’, con- sists of an aliphatic sulfon flanked by a thioether group separated by two methylene groups. This arrangement

trends in analytical chemistry, vol. 7, no. I, 1988 11

forms a recognition domain for im- munoglobulins which is explained by an electron donor-acceptor mecha- nism that primarily involves the indol side chain of tryptophan.

The application of affinity tech- niques to diagnostics was covered by Karube, and by Scheller. Both pre- sentations dealt with biosensors of exceptional capabilities and the basic principles of their functioning were reported. However, anyone hoping for some information on the con- struction of these sensors would have been disappointed.

In the session on industrial and biotechnological applications of af- finity techniques, the presentation of

UhlCn attracted a lot of interest. He showed how to facilitate the isolation of proteins manufactured by geneti- cally converted microorganisms from culture media. By attaching, for ex- ample, a DNA sequence coding for Staphylococcal protein A to the DNA sequence for the protein de- sired and transforming the host orga- nism by this extended gene, the re- combinant protein produced can be easily extracted from the culture me- dium by filtration through an IgG- coated affinity support. The final product is then obtained by chemical or enzymatic cleavage of the chimer- ical protein at the fusion point pre- viously altered by mutation so as to

provide specific cleavage sites. The scientific events of the meet-

ing were reviewed by HjertCn in a splendid summary lecture. It is fortu- nate for those who could not attend this meeting that all the oral contri- butions will be published in the ‘Mac- romolecular Symposia Series’ of Hiithig & Wepf Verlag (Basel, Hei- delberg, New York) early 1988.

WERNER MijLLER

Professor Werner Miiller is at the Chem- ical Reagents Division, R&D Chrom- atography, E. Merck, Frankfurterstrasse 250,610O Darmstadt 1, F.R.G.

100th Anniversary of the Michelson interferometer

A report on the 6th Conference on Fourier Transform Spectroscopy, held in Vienna, Austria, 24-28 August, 1987

More than 500 scientists attended the very successful conference on Fou- rier transform spectroscopy (FTS) at the Technical University Vienna, Austria. The conference was hosted by the Austrian Society for Micro- chemistry and Analytical Chemistry and celebrated the 100th anniversary of the publication of the article by A. A. Michelson and E. W. Morley [Phil. Mug. 24 (1887) 463, ‘On a Method of Making the Wave-length

of Sodium Light the Actual and Prac-

tical Standard of Length’]. This con- tains the first description of how the Michelson interferometer can also be used for spectroscopy. A special poster designed by Connes and Kellner, commemorated this mile- stone for spectroscopy.

The 20 plenary speakers provided state-of-the-art reports of FTS in chemistry, physics and mathematics. Theory and new applications were also covered. The conference was characterized by significant novel

contributions. There is no way to do justice to all of them in this short sur- vey.

For the first time in this conference series, Cooley, co-inventor of the ‘Cooley-Tukey-FFT-Algorithmus’, described how he actually re-discov- ered his now famous algorithm in 1965, which was first derived by C. F. Gauss. Griffiths presented the first unified approach to the chroma- tography - FTIR-interface for gas, liquid and supercritical fluid chroma- tography.

After a particularly moving eulogy by Grasselli to the unforgettable To- mas Hirschfeld, in which she com- pared his genius to that of Michelson, Chase reported on Fourier transform Raman spectroscopy, another world premiere at this meeting and still in- fluenced by the thrilling ideas of Hirschfeld.

Nafie compared two methods for sensitivity increase in surface analy- sis by polarization modulation FTS. There are many significant advan- tages with the novel interferometer modulation compared to double modulation, especially in the far IR region.

In his lecture ‘Intermolecular In-

teractions in Condensed Matter’ Knijzinger treated an experimentally demanding subject of special impor- tance to the chemist. Farmer - flown in from his ozone hole experi- ments in Chile - reported exten- sively on the now accomplished quantitative evaluation of the space- shuttle experiments in the strato- sphere two years ago. He uncovered six new gaseous pollutants in his non- target-approach using the sun as IR light-source. A further exciting ses- sion on far infrared Fourier trans- form spectroscopy of semiconduc- tors was presented by Haller. Neckel covered the spectroelectrochemistry of conducting organic polymers such as polyaniline and its behavior in the IR-range upon electrochemical dop- ing. The present state of the art and new aspects in catalysis were pre- sented by Mink; dispersive Fourier transform spectroscopy by Birch; FIS and the exploration of the solar system, by De Bergh; high resolution and the accurate measurement of in- tensities by Johns; high precision FIS by Brault (after his lecture a particularly vivid discussion en- sued!); advanced spectral processing methods by Cameron, and FTS using