Salt‐assisted acetonitrile extraction and HPLC‐QTOF‐MS/MS detection for residues of multiple classes of pesticides in human serum samples

Abstract

Detecting pesticide residues in human serum is a challenging process. In this study we developed and validated a method for the extraction and recovery of residues of multiple classes of pesticides from serum using one reagent. Salt‐assisted acetonitrile extraction and high‐performance liquid chromatography with quadrupole time of flight tandem mass spectrometry were used to quantitate 34 pesticides classified in nine groups of chemicals in human serum samples, which are frequently detected in food. The recoveries for 33 of analyzed pesticides ranged from 86 to 112% with relative standard deviations below 15%. The limits of quantitation and linearity of 31 of the pesticides were 1 µg/L and >0.990, respectively. The lower limit of quantitation has been reported in the literature particularly for multi‐classes pesticide mixtures in human serum. The salt–acetonitrile reagent was allowed to achieve good recoveries and detection limits, which could be attributed to salt altering the solvent polarity, preferentially collecting the organic phase in the solution, and promoting the extraction. The developed method was applied for two organophosphate pesticide metabolites, diethylphosphate and 3,5,6‐trichloro‐2‐pyridinol, in serum from rats that were fed a nonlethal quantity of chlorpyrifos. The concentrations of these two were 252.18 ± 15.47 and 0.63 ± 0.23 µg/L, respectively.

No‐additive salting‐out liquid–liquid extraction—A tool for purification of positively charged compounds from highly salted reaction mixtures

“…The SALLE technique usually utilizes an appropriate salt and solvent (e.g., water-ACN) system, and it is used to extract the target analyte into the ACN-rich layer [7][8][9][10][11][12]. The suggested extraction protocol was performed with no additional salts added to the reaction mixture (no-additive SALLE).…”

“…In the analytical and bioanalytical chemistry, the technique is called salting-out liquid-liquid extraction or salting-out assisted liquidliquid extraction (SALLE). The compounds of interest are extracted into the organic solvent-rich layer, mainly to acetonitrile, which utilization prevails over other solvents [7][8][9]. The development of the SALLE technique over the years can be found in comprehensive reviews published by Majors [10], Tang and Weng [11], or in the book Sample Preparation in LC-MS bioanalysis [12].…”

A validated square‐wave voltammetric method for simultaneous determination of two insecticide metabolites: 3,5,6‐trichloro‐2‐pyridinol and malathion diacid and their binding constants with human serum albumin

“…Detection of chlorpyrifos and its two major metabolites of degradation (TCP and O,O'-diethylthiophosphoric acid) has been developed by the ELISA method [11]. However, the most common methods found in the literature for quantifying the two metabolites under this study are either HPLC/MS/MS or GC/MS/MS [12][13][14][15][16][17].…”

Determination of eight endocrine disruptor pesticides in bovine milk at trace levels by dispersive liquid‐liquid microextraction followed by GC‐MS determination

“…These pesticides usually occur at low concentrations in the environment and are determined by GC [15–17], HPLC [18, 19] and, chromatography‐MS [20 ‐ 29].…”