Detection of 11 carbamate pesticide residues in raw and pasteurized camel milk samples using liquid chromatography tandem mass spectrometry: Method development, method validation, and health risk assessment

Abstract

This study aimed to use ultra-high-performance liquid chromatography coupled to a triple-quadrupole mass spectrometer to detect 11 carbamate pesticide residues in raw and pasteurized camel milk samples collected from the United Arab Emirates. A method was developed and validated by evaluating limits of detection, limits of quantitation, linearity, extraction recovery, repeatability, intermediate precision, and matrix effect. Due to the high protein and fat content in camel milk, a sample preparation step was necessary to avoid potential interference during analysis. For this purpose, 5 different liquid-liquid extraction techniques were evaluated to determine their efficiency in extracting carbamate pesticides from camel milk. The established method demonstrated high accuracy and precision. The matrix effect for all carbamate pesticides was observed to fall within the soft range, indicating its negligible effect. Remarkably, detection limits for all carbamates were as low as 0.01 μg/kg. Additionally, the coefficients of determination were >0.998, demonstrating excellent linearity. A total of 17 camel milk samples were analyzed, and only one sample was found to be free from any carbamate residues. The remaining 16 samples contained at least one carbamate residue, yet all detected concentrations were below the recommended maximum residue limits set by Codex Alimentarius and the European Union pesticide databases. Nonetheless, it is worth noting that the detected levels of ethiofencarb in 3 samples were close to the borderline of the maximum residue limit. To assess the health risk for consumers of camel milk, the hazard index values of carbofuran, carbaryl, and propoxur were calculated. The hazard index values for these 3 carbamate pesticides were all below 1, indicating that camel milk consumers are not at risk from these residues.