HPLC-MS/MS method for the measurement of insecticide degradates in baby food

Abstract

A solid phase extraction method was developed to isolate four insecticide degradates from baby food that were measured subsequently using high-performance liquid chromatography-tandem mass spectrometry. The degradates [parent insecticide] measured were malathion dicarboxylic acid [malathion], 3,5,6-trichloro-2-pyridinol [chlorpyrifos, chlorpyrifos methyl] (TCPy), cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid [permethrin, cypermethrin, cyfluthrin], and 3-phenoxybenzoic acid [general pyrethroid]. All degradates produced recoveries between 80 and 120% except TCPy in fruit (122% recovery), and all relative standard deviations were <16%. Use of this method demonstrated that insecticide degradates were found in baby foods frequently purchased in the United States, supporting the need for this method. These data will assist in differentiating whether biomarker levels of insecticide metabolites are the result of exposures to the toxic insecticide or its preformed degradate.

Figure 1

Comparison of chromatographic peaks for chromatogram of TCPy: (top) sample with no detection; (middle) peak detected at 7.321 min in an apple juice sample with a concentration below the LOQ (scale identical to top); (bottom) spiked quality control materials at 10 ng/g equivalent (note factor of 10 change in scale).

Figure 2

Calibration curve for 3-phenoxybenzoic acid, a degradate of many pyrethroid insecticides, in vegetables. All calibration points were injected in triplicate, and all points are present on the graph.