Quantitative Multiclass Pesticide Residue Analysis in Apple, Pear, and Grape by Modified QuEChERS and Liquid Chromatography Coupled to High-Resolution Mass Spectrometry.

Most of the analytical methods currently applied in food control laboratories are focused on the determination of target compounds using LC coupled to tandem MS, which is an effective technique, but low-resolution MS is limited. Thus, a method for determination of pesticide multiresidues in fruits (pear, apple, and grape) using a modified quick, easy, cheap, effective, rugged, and safe method and LC coupled to quadrupole time-of-flight (Q-TOF) MS was developed and validated. The proposed method showed good linearity (r2 > 0.99) from 1 to 100 µg/L. Recoveries for blank samples spiked at 0.01, 0.04, and 0.10 mg/kg were between 66 and 122%, with RSDs <28%. Respective LOQs for apple, pear, and grape matrixes were 0.01 mg/kg for 112, 120, and 118 compounds, and 0.04 mg/kg for 22, 12, and 17 compounds, and average mass accuracy error was 3.2 ppm. LC with Q-TOF MS detection using protonated molecular ion and/or adducts and mass accuracy provided reliability for the method. The proposed method is effective for pesticide residue determination in apple, pear, and grape samples, proving that high-resolution MS using full scan mode can be a powerful and reliable technique for quantification purposes, being adequate for application in the surveillance of maximum residue limits set by different legislations.

Liquid chromatography with high resolution mass spectrometry for identification of organic contaminants in fish fillet: screening and quantification assessment using two scan modes for data acquisition.

This study proposed a strategy to identify and quantify 182 organic contaminants from different chemical classes, as for instance pesticides, veterinary drug and personal care products, in fish fillet using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QToF/MS). For this purpose, two different scan methods (full scan and all ions MS/MS) were evaluated to assess the best option for screening analysis in spiked fish fillet samples. In general, full scan acquisition was found to be more reliable (84%) in the automatic identification and quantification when compared to all ions MS/MS with 72% of the compounds detected. Additionally, a qualitative automatic search showed a mass accuracy error below 5ppm for 77% of the compounds in full scan mode compared to only 52% in all ions MS/MS scan. However, all ions MS/MS provides fragmentation information of the target compounds. Undoubtedly, structural information of a wide number of compounds can be obtained using high resolution mass spectrometry (HRMS), but it is necessary thoroughly assess it, in order to choose the best scan mode.

Transformation of ionophore antimicrobials in poultry litter during pilot-scale composting.

Ionophores are the second top selling class of antimicrobials used in food-producing animals in the United States. In chickens, ionophores are used as feed additives to control coccidiosis; up to 80% of administered ionophores are excreted in the litter. Because poultry litter is commonly used to fertilize agricultural fields, ionophore residues in litter have become contaminants of emerging concern. This study aims to develop a liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify ionophores, and identify their transformation products (TPs) in poultry litter after on-farm pilot-scale composting. The validation parameters of the optimized method showed good accuracy, ranging from 71 to 119% recovery and relative standard deviation (precision) of ≤19% at three different concentration levels (10, 50 and 100 µg/kg). Monensin, salinomycin and narasin, were detected in the poultry litter samples prior to composting at 290.0 ± 40, 426 ± 46, and 3113 ± 318 µg kg(-1), respectively. This study also aims to investigate the effect of different composting conditions on the removal of ionophores, such as the effect of turning or aeration. Results revealed a 13-68% reduction in ionophore concentrations after 150 d of composting, depending on whether the compost was aerated, turned, or subjected to a combination of both aeration and turning. Three transformation products and one metabolite of ionophores were identified in the composted litter using high-resolution liquid chromatography with quadrupole time-of-flight mass spectrometry (LC-QToF/MS).

Development of a multiresidue method for the determination of endocrine disrupters in fish fillet using gas chromatography-triple quadrupole tandem mass spectrometry.

Endocrine Disrupter Compounds (EDCs) are responsible for alterations in the endocrine system functions. Aquatic organisms are able to accumulate EDCs residues, being the major source of contamination for top predators and human consumers. This study aimed to develop and validate a method for the determination of 40 EDCs in fish fillet using modified QuEChERS and Gas Chromatography coupled with Mass Spectrometry in tandem (GC-MS/MS). A factorial design was used to optimize the extraction procedure. Method validation presented recoveries from 70.1% to 120.0% with RSD<20% and method limit of detection ranged from 0.3 to 7.5 µg kg(-1), showing good accuracy and precision. This method was successfully applied to the analysis of fish fillet from different species and residues of bisphenol A, chlorpyrifos and bifenthrin were detected. The proposed method proved to be effective for the determination of EDCs in fish fillet at very low concentration levels.

Determining organic pollutants in automotive industry sludge.

In Brazil, the policy for disposing industrial sludge is changing from an emphasis on using controlled landfills to other treatment or co-processing methods; however, the monitoring of organic pollutants is not mandatory. The present study evaluated two general screening methods for organic pollutants in sludge generated in an automotive industrial complex in southern Brazil. The screening was performed using Soxhlet and sonication extractions and Gas Chromatograph coupled with Quadrupole Mass Spectrometry (GC/qMS). It was concluded that both techniques were effective and that most of the compounds identified were alkanes, phenols and esters. Important pollutants were detected in the sludge, which confirms the necessity of monitoring this type of residue.