STABILIZED FILTER-SUPPORTED BILAYER-LIPID MEMBRANES (BLMS) FOR AUTOMATED FLOW MONITORING OF COMPOUNDS OF CLINICAL, PHARMACEUTICAL, ENVIRONMENTAL AND INDUSTRIAL INTEREST

This paper describes the results of analytical applications of electro chemical biosensors based on bilayer lipid membranes (BLMs) Sor the au tomated rapid and sensitive flow monitoring of substrates of hydrolyti c enzymes, antigens and triazine herbicides. BLM's, composed of mixtur es of egg phosphatidylcholine (egg PC) and dipalmitoylphosphatidic aci d (DPPA), were supported on ultrafiltration membranes (glass microfibr e or polycarbonate) which were found to enhance their stability fos fl ow experiments. The proteins (enzymes, antibodies) were incorporated i nto a floating lipid matrix at an air-electrolyte interface, and then a casting procedure was used to deliver the lipid onto the filter supp orts for BLM formation. Injections of the analyte were made into flowi ng streams of the carrier electrolyte solution and a current transient signal was obtained with a magnitude related to the analyte concentra tion. Substrates of hydrolytic enzyme reactions (acetylcholine, urea a nd penicillin) could be determined at the micromolar level with a maxi mum rate of 220 samples/h, whereas antigens (thyroxin) and triazine he rbicides (simazine, atrazine and propazine) could be monitored at the nanomolar level in less than 2 min. The time of appearance of the tran sient response obtained for herbicides was increased to the order of s imazine, atrazine and propazine which has permitted analysis of these triazines in mixtures.