Determination of multiclass herbicides in sediments and aquatic products using QuECHERS combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and its application to risk assessment of rice-fish co-culture system in China

Establishment of a Method for the Detection of Indaziflam, Spirotetramat, Cyantraniliprole, and Their Metabolites and Application for Fruit and Vegetable Risk Assessment

The presence of pesticides in foodstuffs has received increasing amount of attention worldwide. In this study, an efficient and sensitive QuEChERS/HPLC-MS/MS-based method was established for the simultaneous detection of indaziflam, cyantraniliprole, spirotetramat, and their metabolites on fruits and vegetables. The purification procedure and detection condition parameters were optimized. Good precision and reproducibility were found for the method, and the average recoveries of the target analytes ranged from 71 to 118%, with the relative standard deviation ranging from 2 to 12%. The limits of quantification and the limits of detection were 1-5 and 0.3-1.5 μg kg^-1, respectively. The proposed method was used to detect three pesticides and their metabolites in fruit and vegetable samples collected from China's major producing regions. Furthermore, the dietary risk posed by the pesticide residues on fruits and vegetables was evaluated by risk quotients (RQs) and risk probabilities (RPs). The RQ and RP values were less than 100% for Chinese consumers. This study not only provides a reliable analytical method for monitoring purposes but also serves as a significant guide for food safety and export.

Simultaneous Determination of Seven Pesticides and Metabolite Residues in Litchi and Longan through High-Performance Liquid Chromatography-Tandem Mass Spectrometry with Modified QuEChERS

This study established a QuEChERS high-performance liquid chromatography/tandem triple-quadrupole mass spectrometry method for determining azoxystrobin, pyraclostrobin, picoxystrobin, difenoconazole, chlorantraniliprole, imidacloprid, and cyantraniliprole and its metabolite (IN-J9Z38) in litchi and longan, and applied this method to the real samples. The residues in samples were extracted with acetonitrile and purified with nano-ZrO2, C18, and PSA. The samples were then detected with multireactive ion monitoring and electrospray ionization in the positive ion mode and quantified using the external matrix-matched standard method. The results showed good linearities for the eight analytes in the range of 1−100 μg/L, with correlation coefficients (r2) of >0.99. The limit of quantification was 1−10 μg/kg, and the limit of detection was 0.3−3 μg/kg. Average recovery from litchi and longan was 81−99%, with the relative standard deviation of 3.5−8.4% at fortified concentrations of 1, 10, and 100 μg/kg. The developed method is simple, rapid, efficient, and sensitive. It allowed the rapid screening, monitoring, and confirming of the aforementioned seven pesticides and a metabolite in litchi and longan.

Pulsed-sonochemiluminescence combined with molecularly imprinted polymerized high internal phase emulsion adsorbent for determination of bentazone

A small low-power humidifier with a simple programmable on/off switch was used as a pulsed ultrasound generator. Using this tool, a novel sonochemiluminescence (SCL) method was developed to determine bentazone. To the best of our knowledge, no chemiluminescence method has been proposed to determine this pesticide. Only five studies have been proposed for SCL quantitative applications so far. Therefore, revealing new aspects of SCL promises to develop analytical methods for the quantitative determination of different substances. A molecularly imprinted polymerized high internal phase emulsion (MIP-polyHIPE) was synthesized, bentazone separated from aqueous solutions, and pre-concentrated by the MIP-polyHIPE foam. The adsorption of bentazone on the MIP-polyHIPE adsorbent was theoretically studied by density functional theory through molecular dynamics simulation. Both experimental and simulation results indicated removal and pre-concentration of bentazone by the MIP-polyHIPE adsorbent. Using the proposed SCL method and without pre-concentration process, a linear dynamic range (LDR) of 2.5 × 10^-7-5.0 × 10^-5 mol L^-1 and a limit of detection (LOD) of 8.4 × 10^-8 mol L^-1 were obtained for bentazone with a relative standard deviation of 2.64%. The LDR and LOD were improved to 2.6 × 10^-9-2.0 × 10^-7 mol L^-1 and 8.8 × 10^-10 mol L^-1, respectively, using MIP-polyHIPE adsorbents. The method's application was evaluated by removing and pre-concentration of bentazone from water samples, including well, river, and tap water. The results showed that the pre-concentration factor and recovery percentages were 113-131 times and 93-106%, respectively, using the MIP-polyHIPE absorbent.

Effects of chronic prometryn exposure on antioxidative status, intestinal morphology, and microbiota in sea cucumber (Apostichopus japonicus)

Prometryn is an occasional triazine herbicide used in aquaculture to kill algae. However, deposition of prometryn at the bottom of the pond poses a potential threat to aquatic animals, especially benthos, such as the sea cucumber. This study investigated the toxic effects of prometryn oral exposure on antioxidants, and the intestinal histomorphology and microbiome of sea cucumbers. Results showed that the accumulation of prometryn in the intestine, respiratory tree, and body wall decreased sequentially under the same level. Severe pathological damages were observed in the intestines of sea cucumbers fed with 0.080 and 1.595 g/kg prometryn (measured concentration). Moreover, hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) concentrations were significantly increased in prometryn treatment groups compared to the control group (P < 0.05), while the catalase (CAT) activity was significantly decreased (P < 0.05) in the coelomic fluid of treatment groups. At the phylum level, the abundance of Proteobacteria was significantly higher in the 0.080 g/kg treatment group than in the control group. In addition, prometryn exposure reduced the diversity of intestinal microflora in sea cucumbers. In conclusion, these results suggest that prometryn has potential toxicity to sea cucumber. Therefore, the harm of prometryn deposited in the sediment to aquatic animals must be a concern in aquaculture.