GC-MS quantification of organophosphorous pesticides extracted from XAD-2 sorbent tube and foam patch matrices

Abstract

This work presents a simple extraction procedure and a sensitive and simultaneous gas chromatography-mass spectrometry (GC-MS) method for quantifying five organophosphorous pesticides – chlorpyrifos, dichlorvos, fenchlorphos, parathion-methyl and prothiofos – currently used in flower and ornamental plant greenhouses, extracted from polyurethane foam dermal patches and sampling tubes packed with XAD-2 sorbent and quartz fiber filter. Analytical performance of the optimized method was evaluated taking into account specificity, selectivity, sensitivity, linearity, matrix effects, recovery and repeatability. Extraction procedures were made by addition of pure toluene to the spiked matrices, followed by gentle stirring or ultrasonic bath immersion. Analytes were eluted with a good resolution between 3.4 min and 13.1 min. Linearity responses were determined within the ranges of 25–550 μg L⁻¹ for XAD-2 (R² > 0.990) and 40–320 μg L⁻¹ for PUF (R² > 0.990). The ANOVA for linear regression (p < 0.001), White test for homoscedasticity (p > 0.05) and t-test for fitting parameters (p < 0.001) indicated that the linear regression model provides a good interpolation of the experimental data. LOD and LOQ values were below 15.70 ηg per sample and 47.56 ηg per sample, respectively. Recoveries ranged from 81.17% to 114.48% with RSD <5%. The absence of significant matrix effects was statistically demonstrated by applying an F-test of equality of variances (p > 0.05), and a two sample t-test assuming equal variances (p > 0.05). The optimized method represents a useful tool for quantification of pesticides at low concentration levels for occupational matrices, allowing the future evaluation of occupational exposure from both inhaling and dermal routes.