The Column - August 2006 - (Page 27)

Q&A August 2006 The Column It's All In The Past Professor Ernst Kenndler from the Institute of Analytical Chemistry at the University of Vienna uses capillary electrophoresis to help conserve and restore museum artefacts. Your work involves using capillary electrophoresis to chromatographic methods. This means that its separation analyse natural organic binders in museum objects. selectivity is uncorrelated with chromatography. In contrast to Why is analysing organic binders important in this other chromatographic methods, it is based on the differential field? migration of ionic analytes in free solution under the influence of an electric field, determined by the size, shape and charge of the Many natural organic materials have been used since ancient separands. times as binders in objects of cultural, artistic or historic value. Separation efficiency and analysis times are similar to other Waxes, egg, drying oils or plant gums were used to adhere chromatography techniques. Sample pre-treatment, which pigments for paintings made with encaustic, tempera, oil or involves the controlled degradation of the oligo- or polymeric watercolour techniques. Others, such as resins, were used for binders to the monomers by hydrolysis is also the same. varnishes on paintings or objects, including statues, music However, subsequent derivatization for chromatographic instruments or furniture, or as hardeners in ceroplastics. It is analysis can be avoided using CE. Derivatization has a number obvious that these materials degrade with time. To develop the of drawbacks: additional manipulation steps are required, proper strategies against this damaging decay, by-products can occur; the excess of the derivatization conservators need to understand the processes reagent and its accompanying impurities can cause causing the deterioration. The first step in this interference; re-arrangement of the analytes can also approach must involve the identification of the occur; and water-free reaction media are often organic binders; then a rational conservation required. Finally, derivatives always reduce treatment suitable to arrest the decay of the separation selectivity because the sample molecules objects can be developed. become chemically more similar as a result of the What advantages does capillary attachment of the derivatizing group. electrophoresis offer over alternative A method that can directly analyse the sample techniques? components has some advantages. Under the conditions we worked out for the analysis of the Capillary electrophoresis CE can be regarded binder components a direct analysis was as a supplementary technique to existing possible. CE turned out to be less methods. For binding media analysis, gas sensitive than chromatographic chromatography GC , gas chromatography

Table of Contents for the Digital Edition of The Column - August 2006

Market Trends & Analysis
Sample Preparation Techniques for Ion Exchange Chromatography
Characterizing Aerosols using Comprehensive Two-dimensional Chromatography
Non-Classical Methods in Comprehensive Two-Dimensional Gas Chromatography
Supplies & Services
Recent Developments in Column Technology Supplement

The Column - August 2006