Multifamily Determination of Phytohormones and Acidic Herbicides in Fruits and Vegetables by Liquid Chromatography-Tandem Mass Spectrometry under Accredited Conditions.

A 7-min multifamily residue method for the simultaneous quantification and confirmation of 8 phytohormones and 27 acidic herbicides in fruit and vegetables using ultra high-performance liquid chromatography (UHPLC) coupled to tandem mass spectrometry (MS/MS) was developed, validated according to SANTE 12682/2019, and accredited according to UNE-EN-ISO/IEC 17025:2017. Due to the special characteristics of these kinds of compounds, a previous step of alkaline hydrolysis was carried out for breaking conjugates that were potentially formed due to the interactions of the analytes with other components present in the matrix. Sample treatment was based on QuEChERS extraction and optimum detection conditions were individually optimized for each analyte. Cucumber (for high water content commodities) and orange (for high acid and high water content samples) were selected as representative matrices. Matrix-matched calibration was used, and all the validation criteria established in the SANTE guidelines were satisfied. Uncertainty estimation for each target compound was included in the validation process. The proposed method was applied to the analysis of more than 450 samples of cucumber, orange, tomato, watermelon, and zucchini during one year. Several compounds, such as 2,4-dichlorophenoxyacetic acid (2,4-D), 4-(3-indolyl)butyric acid (IBA), dichlorprop (2,4-DP), 2-methyl-4-chlorophenoxy acetic acid (MCPA), and triclopyr were found, but always at concentrations lower than the maximum residue level (MRL) regulated by the EU.

Headspace solid-phase microextraction coupled to gas chromatography-tandem mass spectrometry for the determination of haloanisoles in sparkling (cava and cider) and non-sparkling (wine) alcoholic beverages.

A highly sensitive analytical method was developed to determine 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), 2,4,6-tribromoanisole (TBA) and 2,3,4,5,6-pentachloroanisole (PCA) in sparkling alcoholic beverages. The method was based on the use of headspace solid-phase microextraction (HS-SPME) using a polydimethylsiloxane (PDMS) fibre. It was coupled to gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS) for the detection and quantification of the target haloanisoles. The method was fully automated and no sample preparation was needed. The method was validated for alcoholic beverages. The influence of CO2 on the extraction efficiency was also evaluated for the studied sparkling drinks (cava and cider). All the calibration curves showed good linearity (R2 > 0.98) within the tested range (1-50 ng l-1). Recoveries were evaluated at three different levels (1, 5 and 50 ng l-1) and were always between 71% and 119%. Precision was expressed as relative standard deviation (RSD), and was evaluated as intra- and inter-day precisions, with values ≤ 22% in both cases. Limits of quantitation (LOQs) were ≤ 0.91 ng l-1, which are below the sensory threshold levels for such compounds in humans. The validated method was applied to commercial samples, 10 cavas and 10 ciders, but it was also used for the analysis of nine red wines and four white wines, demonstrating the further applicability of the proposed method to non-sparkling beverages. TCA was detected in most samples at up to 0.45 ng l-1.

Determination of quaternary ammonium compounds in oranges and cucumbers using QuEChERS extraction and ultra-performance liquid chromatography/tandem mass spectrometry.

A simple and fast method has been developed for determining relevant quaternary ammonium compounds in cucumber and orange samples. The target compounds were benzoalkonium chloride (BAC-10, BAC-12, BAC-14, and BAC-16), didecyldimethylammonium chloride, and benzethonium chloride, all frequently used biocides in the agrifood industry. An extraction based on the buffered Quick, Easy, Cheap, Effective, Rugged, and Safe method and determination by ultra-performance LC/MS/MS that eluted the biocides in less than 5 min were used. The method was fully validated and implemented in a UNE-EN-ISO/IEC 17025 accredited laboratory for its application to the analysis of real samples. Performance characteristics of the method are reported, including an estimation of measurement uncertainty. Calibration curves were set between 0.01 and 0.150 mg/kg, LOD values were always between 0.4 and 1.0 microg/kg, LOQ values were in the range 1-4 microg/kg, recovery was between 81 and 115%, intraday and interday precision were always lower than 17% (expressed as RSD), and expanded uncertainty was always lower than 40%. The validation was accomplished for the two studied matrixes at spiking concentrations of 0.011 and 0.050 mg/kg. The method has been applied to the analysis of 30 cucumber and orange samples that were found to contain concentrations of BAC-12 that ranged between 0.015 and 0.210 mg/kg and of BAC-14 between 0.018 and 0.081 mg/kg.

Application of gas chromatography coupled to triple quadrupole mass spectrometry for the multiresidue analysis of pesticides in olive oil.

A new multiresidue method has been developed and validated for the simultaneous determination of 100 pesticide residues in olive oil. The determination of pesticide residues was carried out in only 19 min by gas chromatography coupled to tandem mass spectrometry using a triple quadrupole mass analyzer. The mass spectrometer was operated in electron ionization and the selection reaction monitoring mode was used, acquiring two or three fragmentation reactions per compound. Two extraction processes were studied, and an evaluation of the stability and sensitivity of the chromatographic system has been performed for the tested extraction procedures. The final proposed methodology was based on a liquid-liquid partition with an n-hexane/acetonitrile mixture followed by a gel permeation chromatography cleanup step. An adequate lineal relation was obtained in the studied concentration range (10-200 microg kg (-1)); the recovery values were in the range 70-110% for the two levels of concentration studied: 12 and 50 microg kg (-1). Precision values, expressed as relative standard deviation, were lower than 18% at the aforementioned spiking levels; detection limits, confirmation limits, and quantitation limits were below or equal to 1.9, 2.6, and 3.6 microg kg (-1), respectively. The developed methodology was applied to the analysis of pesticide residues in real samples of olive oil from the south of Spain.

Application of low-pressure gas chromatography/tandem mass spectrometry to the determination of pesticide residues in tropical fruits.

A multiresidue method has been developed for determining pesticide residues in the tropical fruits kiwi, custard apple, and mango. The intended purpose of the method is for regulatory analyses of commodities for pesticides that have established maximum residue limits. A fast and simple extraction method with cyclohexane-ethyl acetate (1 + 1, v/v) and a high-speed homogenizer was optimized. Pressurized liquid extraction was evaluated as an alternative automated extraction technique. The pesticide residues were determined by using low-pressure gas chromatography coupled to tandem mass spectrometry. The proposed methodology was validated for each matrix. Pesticide recoveries ranged from 70 to 110%, with repeatability relative standard deviations of < or = 18% at spiking levels of 12 and 50 microg/kg. The limits of quantitation were in the range of 0.03-6.17 microg/kg, and the limits of detection were between 0.01 and 3.75 microg/kg. Mango can be selected as a representative matrix for calibration on the basis of the results of a potential matrix effect study. The method was successfully applied to the determination of pesticide residues in real samples in Spain.