California Department of Food and Agriculture (CDFA) Center for Analytical Chemistry (CAC) Environmental Safety Laboratory scientists Bahar Nakhjavan, Jason Bland and Maryam Khosravifard had their article, “Optimization of a Multiresidue Analysis of 65 Pesticides in Surface Water Using Solid-Phase Extraction by LC-MS/MS,” published November 1 in the academic journal Molecules.
The article reviews an improved method developed in the CAC laboratories. Historically, CAC applied a liquid extraction technique to determine 59 pesticide compounds in surface water monitoring. This improved method utilizes a solid phase extraction technique that can determine an expanded 65 compounds. This new technique is faster, simpler, and needs less sample volume (100 ml vs. 1,000 ml) and solvent volume (35 ml vs. 1,000 ml) for extraction, making it more environmentally friendly.
An analytical method was developed and validated for simultaneous quantitation of 65 pesticides, including one single solid-phase extraction (SPE) procedure in surface water by liquid chromatography coupled to tandem mass spectroscopy. Different parameters that have an influence on extraction efficiency were evaluated in this research. Different types of cartridges, elution solvents, and sorbent drying time were investigated, and the most appropriate one was selected. Moreover, various pretreatment techniques were applied to remove sediments from water without the loss of pesticides. Centrifugation was introduced as the best option at the beginning of sample preparation to resolve the clogging of the sorbent cartridges. The recoveries of all pesticides ranged from 70% to 120%, with a relative standard deviation of less than 13.7%. The feasibility of the method was evaluated on 10 surface water samples with different concentrations of sand, sediment, and particles.
Nakhjavan, B., Bland, J., Khosravifard, M., “Optimization of a Multiresidue Analysis of 65 Pesticides in Surface Water Using Solid-Phase Extraction by LC-MS/MS.” Molecules, 2021, 26 (21), 6627; https://doi.org/10.3390/molecules26216627.