Bisphenol A (BPA) concentrations were determined in canned beverages, fruits, vegetables, and fat-containing foodstuffs bought in Austrian supermarkets. The analysis method consisted of sol-gel immunoaffinity chromatography followed by high-performance liquid chromatography with fluorescence detection. With one exception traces of BPA were detected in all samples. BPA recovery strongly depended on the food matrix, ranging from 27% in goulash to 103% in a lemon soft drink. The results obtained allow a more realistic picture of the BPA exposure caused by cans with an epoxy resin protective coating because--in contrast to several previous studies--only those fractions of the can contents that are actually consumed were analyzed. BPA concentrations ranging from 0.1 ng/mL (lemon soft drink) to 38 ng/g (ready-to eat soup from Thailand) were significantly lower than the European Union migration limit of 0.6 mg of BPA/kg of food.

Microgravimetric sensors have been developed for detection of insulin by using quartz crystal microbalances as transducers, in combination with sensitive layers. Natural antibodies as coatings were compared with biomimetic materials to fabricate mass-sensitive sensors. For this purpose polyurethane was surface imprinted by insulin, which acts as a synthetic receptor for reversible analyte inclusion. The sensor responses for insulin give a pronounced concentration dependence, with a detection limit down to 1 μg/mL and below. Selectivity studies reveal that these structured polymers lead to differentiation between insulin and glargine. Moreover, antibody replicae were generated by a double imprinting process. Thus, biological recognition capabilities of immunoglobulins are transferred to synthetic polymers. In the first step, natural-immunoglobulin-imprinted nanoparticles were synthesized. Subsequently, these templated particles were utilized for creating positive images of natural antibodies on polymer layers. These synthetic coatings, which are more robust than natural analogues, can be produced in large amount. These biomimetic sensors are useful in the biotechnology of insulin monitoring.

Biological information such as recognition abilities of antibodies can be transferred to man-made systems by imprinting. For instance, sensor layers with insulin-selective cavities yield similar selectivity and sensitivity as IgG. True "artificial antibodies" are achieved by synthesizing "polymer copies" retaining the original binding properties of anti-insulin IgG via two-step imprinting.

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