Miniaturized QuEChERS method for determination of 97 pesticide residues in wine by ultra-high performance liquid chromatography coupled with tandem mass spectrometry

A miniaturized QuEChERS and UPLC-MS/MS method for the determination of mycotoxins in cashew nuts

This study aimed to develop and validate a multi-mycotoxin analysis method applied to cashew nuts by employing a miniaturized QuEChERS method followed by determination by ultra-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Satisfactory recoveries for the concentrations 1, 10 and 30 ng g-1, ranging from 66% (fumonisin B1) to 110% (ochratoxin A) and relative standard deviations lower than 9% (fumonisin B2) were obtained for the target compounds. Limits of quantification ranged from 0.004 ng g-1 (sterigmatocystin) to 0.59 ng g-1 (alternariol). The applicability of the analytical method was verified by analyzing 30 cashew nut samples from the city of Rio de Janeiro, RJ, southeastern Brazil. Aflatoxins M1, G2, G1, B2, B1, ochratoxin A and sterigmatocystin were detected, respectively, in 27%, 10%, 17%, 30%, 30%, 30% and 50% of the analyzed samples, at maximum concentrations of 0.56, 0.67, 1.43, 2.02, 4.93, 4.81, and 0.35 ng g-1. The maximum limit established by Brazilian legislation for aflatoxins was not exceeded by any of the analyzed samples.

Determination of quinclorac and quinclorac methyl ester in honey by online SPE-UPLC-MS/MS

A method employing online solid phase extraction (SPE) coupled to UPLC-MS/MS was developed for the determination of residues of the acid herbicide quinclorac plus its transformation product, quinclorac methyl ester, in honey. The analytical method involved dissolving the honey in a mixture of methanol:water followed by direct injection into a two-dimensional UPLC system which is used to perform an automated SPE cleanup on a reusable phenyl cartridge prior to the target analytes being transferred onto an analytical UPLC column for subsequent chromatographic separation followed by MS/MS detection. The limits of quantitation for quinclorac and quinclorac methyl ester in honey were both set at 0.5 µg kg-1 and the method detection limit was estimated to be 0.012 µg kg-1 for each compound. The working analytical range (0.5-100 µg kg-1) was validated by analysing a series of spiked replicate honey samples. The method was applied to the analysis of various honeys obtained from numerous different commercial sources. Quinclorac was detected in 9 out of 30 samples at concentrations ranging from 0.6 to 31.5 µg kg-1. Quinclorac methyl ester, which is estimated to be significantly more toxic than the parent herbicide itself, was not detected in any honey sample.

Coconut shell biochar application in liquid-solid microextraction of triazine herbicides from multi-media environmental samples

A rapid, fast, widely applicable liquid-solid microextraction and purification method of triazine herbicides (TRZHs) in muti-media samples using salting-out assisted liquid-liquid extraction (SALLE) combined with self-assembled monolithic spin columns-solid phase micro extraction (MSC-SPME) was developed. Environmentally friendly coconut shell biochar (CSB) was used as the adsorbents of MSC-SPME. Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was the separation and determination method. The adsorption kinetics and isotherms were investigated to indicate the interaction between CSB and TRZHs. Several parameters influencing the liquid-solid microextraction efficiency, such as sample pH, salting-out solution volume and pH, sample loading speed, elution speed, elution ratio and volume of eluent were systematically investigated with the aid of orthogonal design. The whole extraction process was operated within 10 min. Under the optimum extraction and determination conditions, good linearities for three TRZHs were obtained in a range of 0.10-200.00 ng mL^-1, with linear coefficients (R²) greater than 0.999. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 6.99-11.00 ng L^-1 and 23.33-36.68 ng L^-1, respectively. The recoveries of the three TRZHs in multi-media environmental samples were ranged from 69.00% to 124.72%, with relative standard deviations (RSDs) lower than 0.43%. This SALLE-MSC-SPME-UPLC-MS/MS method was successfully applied to the determination of TRZHs in environmental and food samples and exhibited the advantages of high efficiency and sensitivity, low cost, and environmental friendliness. Compared with the methods published before, CSB-MSC was green, rapid, easy-operated, and reduced the whole cost of the experiment; SALLE combined MSC-SPME eliminated the matrix references effectively; what's more, the SALLE-MSC-SPME-UPLC-MS/MS method could be applied to various sample without complicated sample pretreatment procedure.

R. Rocha C, Teixeira JA, Pereira JAM. Green Extraction Techniques as Advanced Sample Preparation Approaches in Biological, Food, and Environmental Matrices: A Review

Green extraction techniques (GreETs) emerged in the last decade as greener and sustainable alternatives to classical sample preparation procedures aiming to improve the selectivity and sensitivity of analytical methods, simultaneously reducing the deleterious side effects of classical extraction techniques (CETs) for both the operator and the environment. The implementation of improved processes that overcome the main constraints of classical methods in terms of efficiency and ability to minimize or eliminate the use and generation of harmful substances will promote more efficient use of energy and resources in close association with the principles supporting the concept of green chemistry. The current review aims to update the state of the art of some cutting-edge GreETs developed and implemented in recent years focusing on the improvement of the main analytical features, practical aspects, and relevant applications in the biological, food, and environmental fields. Approaches to improve and accelerate the extraction efficiency and to lower solvent consumption, including sorbent-based techniques, such as solid-phase microextraction (SPME) and fabric-phase sorbent extraction (FPSE), and solvent-based techniques (μQuEChERS; micro quick, easy, cheap, effective, rugged, and safe), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), in addition to supercritical fluid extraction (SFE) and pressurized solvent extraction (PSE), are highlighted.

Utilizing a Rapid Multi-Plug Filtration Cleanup Method for 72 Pesticide Residues in Grape Wines Followed by Detection with Gas Chromatography Tandem Mass Spectrometry

A convenient and fast multi-residue method for the efficient identification and quantification of 72 pesticides belonging to different chemical classes in red and white grape wines has been developed. The analysis was based on gas chromatography tandem quadrupole mass spectrometric determination (GC-MS/MS). The optimization strategy involved the selection of the amount of multi-walled carbon nanotubes (MWCNTs) and the number of cleanup procedure cycles for multi-plug filtration cleanup (m-PFC) to achieve ideal recoveries and reduce the sample matrix compounds in the final extracts. The optimized procedure obtained consistent recoveries between 70.2 and 108.8% (70.2 and 108.8% for white wine, and 72.3 and 108.4% for red wine), with relative standard deviations (RSDs) that were generally lower than 9.2% at the three spiking levels of 0.01, 0.05 and 0.1 mg/kg. The linearity was studied in the range between 0.002 and 0.1 mg/kg using pesticide standards prepared both in pure solvent and in the presence of the matrix, showing coefficients of determination (R²) higher than 0.9495 for all the pesticides. To improve accuracy, matrix-matched calibration curves were used for calculating the quantification results. Finally, the method was used successfully for detecting pesticide residues in commercial grape wines.

Accurate mass screening of pesticide residues in wine by modified QuEChERS and LC-hybrid LTQ/Orbitrap-MS

In this research, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction procedure and Ultra-High Performance Liquid Chromatography-Orbitrap-Mass Spectrometry (UHPLC-Orbitrap-MS), were combined to obtain a sensitive and rapid method for the determination of multiclass pesticides in white and red wines. The optimization strategy involved the selection of buffering conditions, by applying different QuEChERS procedures and sorbents for the cleanup step in order to achieve acceptably high recoveries and low co-extractives in the final extracts. Identification was based on both accurate mass and retention time, while further confirmation was achieved by MS fragmentation. The method was evaluated in terms of linearity, recovery, precision, limit of detection (LOD) and quantification (LOQ), matrix effects (ME) and expanded uncertainty. The validated method was successfully applied to real samples (home-made and commercial) revealing the presence of two selected fungicides, in relatively low levels compared to the MRLs defined by the EU for vinification grapes.

Implementing Green Analytical Methodologies Using Solid-Phase Microextraction: A Review

Implementing green analytical methodologies has been one of the main objectives of the analytical chemistry community for the past two decades. Sample preparation and extraction procedures are two parts of analytical method development that can be best adapted to meet the principles of green analytical chemistry. The goal of transitioning to green analytical chemistry is to establish new methods that perform comparably—or superiorly—to traditional methods. The use of assessment tools to provide an objective and concise evaluation of the analytical methods’ adherence to the principles of green analytical chemistry is critical to achieving this goal. In this review, we describe various sample preparation and extraction methods that can be used to increase the greenness of a given analytical method. We gave special emphasis to modern microextraction technologies and their important contributions to the development of new green analytical methods. Several manuscripts in which the greenness of a solid-phase microextraction (SPME) technique was compared to other sample preparation strategies using the Green Analytical Procedure Index (GAPI), a green assessment tool, were reviewed.