Multiresidue pesticide analysis of the medicinal plantOriganum syriacum

Optimization and Application of the QuEChERS-UHPLC-QTOF-MS Method for the Determination of Broflanilide Residues in Agricultural Soils

In this study, the separation conditions of UHPLC-QTOF-MS and the extraction conditions of QuEChERS were optimized. The analytical process for determining Broflanilide residues in different soil types was successfully established and applied to its adsorption, desorption, and leaching in soil. Broflanilide was extracted from soil with acetonitrile and purified using PSA and MgSO4. The modified UHPLC-QTOF-MS method was used for quantification. The average recovery of Broflanilide was between 87.7% and 94.38%, with the RSD lower than 7.6%. In the analysis of adsorption, desorption, and leaching quantities in four soil types, the RSD was less than 9.2%, showing good stability of the method, which can be applied to determine the residue of Broflanilide in different soils.

Optimization of an Analytical Method for Indoxacarb Residues in Fourteen Medicinal Herbs Using GC–μECD, GC–MS/MS and LC–MS/MS

Pesticide residue analysis in medicinal herbs is a challenging task because of the matrix effect and its influence on quantitative analysis despite the continuous development of several new analytical methods and instrumentations. In this study, a modified QuEChERS method was developed for the analysis of indoxacarb residue in medicinal herbs by using the conventional instrument, gas chromatography micro-electron-capture-detector (GC–μECD), and comparing it with gas chromatography–tandem mass spectrometry (GC–MS/MS) and liquid chromatography–tandem mass spectrometry (LC–MS/MS). Samples were extracted with acetonitrile and purified using an NH2 cartridge. The optimized method efficiently removes the co-extractives and offered a limit of quantification of 0.01 mg kg−1. The GC–μECD analysis results of indoxacarb in seven medicinal herbs out of fourteen species at a fortification level of 0.01 mg kg−1 showed a recovery range of 79.7–117.6%, while the rest showed recovery > 120%. Similarly, the recovery of indoxacarb by GC and LC–MS/SM were 74.1–105.9 and 73.0–99.0%, respectively, with a relative standard deviation of <20%. Matrix effects for the majority of medicinal herbs analyzed by GC–MS/MS were >±20%. Whereas the results for LC–MS/MS were <20%, which was within the acceptable range according to the SANTE/11312/2021 guidelines. Considering the performance of the method and alignment with the regulatory guidelines, LC–MS/MS is recommended for the analysis of indoxacarb in selected medicinal herbs.

Residues Analysis and Dissipation Dynamics of Broflanilide in Rice and Its Related Environmental Samples

Herein, we present a method for the quantitative analysis of broflanilide residues in water, soil, and rice samples from a paddy field in Jiangxi Province, China. The quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was optimized for the extraction and purification of broflanilide residues. Residual broflanilide concentrations in different matrices were then determined by high-performance liquid chromatography (HPLC). The calibration curve of broflanilide showed good linearity in all matrices for concentrations between 0.005 and 1 mg·L⁻¹, with a correlation coefficient greater than 0.99. The matrix effect varied from −69% to −54%, indicating matrix suppression. The average recoveries ranged between 85.82% and 97.46%, with relative standard deviations of 3.29%–8.15%. The limits of detection ranged from 0.16 to 1.67 μg·kg⁻¹, and the limits of quantification were in the range of 0.54 to 5.48 μg·kg⁻¹. Dissipation dynamic tests indicated broflanilide half-lives of 0.46–2.46, 2.09–5.34, and 1.31–3.32 days in soil, water, and rice straw, respectively. Broflanilide was dissipated more rapidly in water than in soil and rice straw. More than 90% of broflanilide residues dissipated within 14 days. The final residues of broflanilide in rice were all below LOQ at harvest.

A Vortex-Assisted Dispersive Liquid-Liquid Microextraction Followed by UPLC-MS/MS for Simultaneous Determination of Pesticides and Aflatoxins in Herbal Tea

A method for detecting the organophosphorus pesticides residue and aflatoxins in China herbal tea has been developed by UPLC-MS/MS coupled with vortex-assisted dispersive liquid-liquid microextraction (DLLME). The extraction conditions for vortex-assisted DLLME extraction were optimized using single-factor experiments and response surface design. The optimum conditions for the experiment were the pH 5.1, 347 µL of chloroform (extraction solvent) and 1614 µL of acetonitrile (dispersive solvent). Under the optimum conditions, the targets were good linearity in the range of 0.1 µg/L⁻25 µg/L and the correlation coefficient above 0.9998. The mean recoveries of all analytes were in the ranged from 70.06%⁻115.65% with RSDs below 8.54%. The detection limits were in the range of 0.001 µg/L⁻0.01µg/L. The proposed method is a fast and effective sample preparation with good enrichment and extraction efficiency, which can simultaneously detect pesticides and aflatoxins in China herbal tea.

Food fraud in oregano: Pesticide residues as adulteration markers

Oregano, a widely used and popular herb, is particularly vulnerable to fraud. Less valued plants, adulterants that are often used for dilution, may introduce into this commodity additional contaminants such as pesticide residues. In this study, more than 400 pesticides were screened in a representative set of 42 genuine and 34 adulterated dried oregano samples collected from various locations across Europe. The results obtained by advanced mass spectrometry-based methods, showed, that some pesticide residues could be detected in virtually all tested samples, nevertheless, on average, higher contamination was found in the adulterated oregano samples. Increased incidence of insecticides such as cyfluthrin, permethrin and cyhalothrin was typical for these samples, moreover, pyriproxyfen was detected exclusively in adulterated samples. Thus, based on a critical assessment of pesticide profiles, suspected adulterated oregano samples can be selected for follow up authenticity testing.

Application of QuEChERS method for simultaneous determination of pesticide residues and PAHs in fresh herbs

The aim of this study was to evaluate the application of quick, easy, cheap, effective, rugged and safe method for simultaneous determination of polycyclic aromatic hydrocarbons and pesticide residues in fresh herbs. In the experiment two extraction solvents and standard types of sorbents were used. The extracts were analyzed using GC-SIM-MS. The results suggest that acetonitrile is more suitable extraction solvent giving more purified samples and better recovery values (71.6 %-116.9 %) with RSD lower than 15 % for most of the compounds. In real samples pesticides were identified in the samples of parsley, tarragon and lovage. In few samples the pesticide levels exceeded the MRL established by EU.