Simultaneous Determination of Nine Commercial Pesticide Formulations by Gas Chromatography Multi-Pesticide with an Internal Standard Method

A gas chromatography multi-pesticide with an internal standard method has been developed to analyze simultaneously separate nine active ingredients (acephate, carbaryl, chlorpyrifos, chlorothalonil, diazinon, dimethoate, malathion, profenofos, quinalphos) in different commercial pesticide formulations. A mixture of pure standard solution spiked with 1-chloro-4fluorobenzene as the internal standard was injected into the GC-ECD and a six point calibration curve that demonstrated a linear range was established for each target compound. Samples of each formulation, mixed with internal standard were analyzed five times to obtain coefficients of variation which are less than 1%. Three concentration levels of each formulation were determined and the results were within the specification with the accuracies obtained were within 98.1% to 101.9%. This method involves a quick analysis, cost effective and without any sample pretreatment process. This measurement method can be very useful for determining pesticide formulations in routine analysis.