Differentiating detection of carbamate insecticides and their metabolites by cholinesterase and bispyridiniumoximes

The development of biochemical methods is a promising possibility for the detection of pesticide residues in water. The inhibition of cholinesterase is a function of the sum of the products of the concentrations and the inhibition values of the carbamates and organophosphorous compounds that are effective inhibitors in this test. A method has been developed to detect carbamates with high sensitivity and to distinguish experimentally among several groups of cholinesterase inhibiting insecticides. Twenty carbamates and metabolites have been selected for the determination of their inhibition values (rate constants k(i)) on five cholinesterases of different biological origin. The influence of obidoxim, bis-(pyridinium-4-aldoxim-1-methyl)-etherdichloride and of a recently synthesized bispyridiniumoxime (1,5)-bis-(pyridinium-4-ethanoxim)-pentanedibromide on the reaction of cholinesterase with several organophosphorous pesticides and carbamates has been investigated.