Determination of organophosphorus aromatic nitro insecticides by using electric-field cell orientation in microbial suspensions

We examined the effect of the cellular metabolism of the organophosphorus aromatic nitro insecticides metaphos and sumithion on the electro-physical properties (EPPs) of Pseudomonas putida C-11, R putida BA-11, and Acinetobacter calcoaceticum A-122 suspensions. We used the dependences of cell-suspension absorbance changes induced by electric-field orientation on the orienting-field frequency in the range 10-10,000 kHz. Substantial orientational-spectrum changes, caused by insecticide action, occurred at frequencies of 10-1000 kHz. The plots of electro-optical effect versus insecticide-concentration were linear over the following concentration ranges: 0.5-3.0 mM metaphos and 0.5-3.5 mM sumithion for P. putida C-I I and BA-11; and 0.5-2.0 mM metaphos and 0.5-2.5 mM sumithion for A. calcoaceticum A-122. We discuss the possibility of developing a biosensor-method based on the measurement of cell-suspension orientational spectra (OS). (C) 2002 Elsevier Science B.V. All rights reserved.