SIMULTANEOUS GAS-CHROMATOGRAPHIC MASS-SPECTROMETRIC QUANTITATION OF THE ALKYLBENZENE INERT COMPONENTS, PESTICIDE MANUFACTURING BY-PRODUCTS AND ACTIVE INGREDIENT IN 2 MALATHION FORMULATIONS

A rapid, reliable and effective method for direct determination of the inert components, manufacturing by-products of the pesticide, and act ive ingredient in two malathion formulations has been established usin g capillary gas chromatography-mass spectrometry (GC-MS) with the inte rnal standard method. The C-2-, C-3- and C-4-alkylbenzenes, the major pesticide manufacturing by-products (O,O,S-trimethylthionophosphate, d iethyl maleate end O,O,O-trimethylthionophosphate), and malathion were resolved, and quantified in the same chromatogram. Structural identif ication was based on MS total ion current data, comparison of GC reten tion times with those of authentic standards, and retention indices. O ,O,S-Trimethylthionophosphate was quantified at 3.57 +/- 0.31% (w/w) i n one malathion formulation. While the malathion contents were within specifications for both formulations, the total alkylbenzene contents were not. (C) 1998 Elsevier Science B.V. All rights reserved.