Simultaneous Analysis and Dietary Exposure Risk Assessment of Fomesafen, Clomazone, Clethodim and Its Two Metabolites in Soybean Ecosystem

Development of an immunoassay based on a specific antibody for the detection of diphenyl ether herbicide fomesafen

Fomesafen belongs to the diphenyl ether herbicide, and is widely used in the control of broadleaf weeds in crop fields due to its high efficiency and good selectivity. The residual of fomesafen in soil has a toxic effect on subsequent sensitive crops and the microbial community structure because of its long residual period. Therefore, an efficient method for detecting fomesafen is critical to guide the correct and reasonable use of this herbicide. Rapid and sensitive immunoassay methods for fomesafen is unavailable due to the lack of specific antibody. In this study, a specific antibody for fomesafen was generated based on rational design of haptens and a sensitive immunoassay method was established. The half maximal inhibitory concentration (IC50) of the immunoassay was 39 ng/mL with a linear range (IC10-90) of 1.92-779.8 ng/mL. In addition, the developed assay had a good correlation with the standard UPLC-MS/MS both in the spike-recovery studies and in the detection of real soil samples. Overall, the developed indirect competitive enzyme immunoassay reported here is important for detecting and quantifying fomesafen contamination in soil and other environmental samples with good sensitivity and high reproducibility.

Optimization of a QuEChERS-LC-MS/MS method for 51 pesticide residues followed by determination of the residue levels and dietary intake risk assessment in foodstuffs

A modified QuEChERS purification-liquid chromatography-tandem mass spectrometry method has been developed to determine 51 pesticide residues with newly established maximum residue limits (MRLs) in foodstuffs. Samples were extracted with acetonitrile under citrate-buffered conditions and purified using a modified QuEChERS method employing hydroxylated MWCNTs, SAX, and C18. The limits of quantification ranged from 0.2 to 9.8 µg/kg. Recoveries in ten different foodstuffs ranged from 70.2% to 117.9%, with relative standard deviations between 2.3% and 19.9% at three spiking levels. This method was applied to analyze 352 market samples, detecting 14 pesticides in 97 samples. Notably, Afidopyropen, cyantraniliprole, and fluxapyroxad residues in vegetables exhibited a consistent pattern of higher levels in the spring and winter and lower levels in the summer and autumn. Moreover, the risk assessments for acute and chronic dietary exposure to the 14 detected pesticides indicated that the %ADI and %ARfD were well below 100%.

Rapid and sensitive detection of clomazone in potato and pumpkin samples using a gold nanoparticle-based lateral-flow strip

In this study, an ultrasensitive monoclonal antibody (mAb) was produced and used to develop a gold nanoparticle-based lateral flow immunochromatographic (ICA) strip for screening of clomazone (CLO) in potato and pumpkin samples. With assayed by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method, the mAb belonging of IgG2 subclass showed a half-maximal inhibitory concentration (IC50) of 3.47 ng/mL and a linear range of detection of 0.43-28.09 ng/mL. A cross-reactivity test revealed that the mAb had good specificity for CLO. The strip assay had a visual limit of detection (LOD) of 5 µg/kg and a cut-off value of 50 µg/kg for CLO pumpkin samples (potato samples was 100 µg/kg) when evaluated with the naked eye. The results were consistent with ic-ELISA and high performance liquid chromatography tandem mass spectrometry (HPLC-MS). Thus, this ICA strip assay represents a potentially tool for on-site and rapid initial detection of CLO in potato and pumpkin samples.

Residues and dietary intake risk assessments of clomazone, fomesafen, haloxyfop-methyl and its metabolite haloxyfop in spring soybean field ecosystem

Soybean is an important oilseed crop, but weed can have a significant effect on soybean yield. Clomazone, fomesafen, and haloxyfop-methyl are high-efficacy herbicides, and the combination of these herbicides shows an ideal effect on weed control. However, the residues of these herbicides and their impacts on human health are still largely unknown. In the current study, a rapid, sensitive, and selective method using modified QuECHERS procedure combined with HPLC-MS/MS was established to detect these herbicides in soybean matrices. The limits of quantification were 0.01, 0.01 and 0.025 mg/kg for haloxyfop-methyl, haloxyfop and fomesafen, and 0.005, 0.005 and 0.0125 mg/kg for clomazone in green soybean, soybean grain, and straw, with the average recoveries ranging from 80% to 107%. The terminal residues of the target compounds were all below the corresponding limits of quantification. The dietary risk assessment showed that the risk quotient values were far below the acceptable human consumption levels.

Techno-economic evaluation and sensitivity analysis of a conceptual design for supercritical water gasification of soybean straw to produce hydrogen

This paper proposes a conceptual design for the catalytic supercritical water gasification of soybean straw. The design consists of four process units for pretreatment, gasification, separation, purification and combustion. The economic feasibility of hydrogen production was evaluated based on a comprehensive cash flow analysis. The economic analysis suggested a minimum selling price of U.S. $1.94/kg for hydrogen. The cost of hydrogen produced is relatively lower compared to that of other biomass conversion processes. Besides, the net rate of return (NRR) estimated was 37.1%. A positive NRR value indicates that the project is profitable from an economic perspective. Sensitivity analysis indicates that the minimum selling price of hydrogen is affected by the feedstock price, utility cost, tax rate and labor cost. Moreover, feedstock price and labor cost show the greatest effect. Other factors such as land cost, working capital and utility cost showed the least effect on the minimum selling price.

Non-Occupational Exposure to Pesticides: Experimental Approaches and Analytical Techniques (from 2019)

BACKGROUND

Pesticide residues are a threat to the health of the global population, not only to farmers, applicators, and other pesticide professionals. Humans are exposed through various routes such as food, skin, and inhalation. This study summarizes the different methods to assess and/or estimate human exposure to pesticide residues of the global population.

METHODS

A systematic search was carried out on Scopus and web of science databases of studies on human exposure to pesticide residues since 2019.

RESULTS

The methods to estimate human health risk can be categorized as direct (determining the exposure through specific biomarkers in human matrices) or indirect (determining the levels in the environment and food and estimating the occurrence). The role that analytical techniques play was analyzed. In both cases, the application of generic solvent extraction and solid-phase extraction (SPE) clean-up, followed by liquid or gas chromatography coupled to mass spectrometry, is decisive. Advances within the analytical techniques have played an unquestionable role.

CONCLUSIONS

All these studies have contributed to an important advance in the knowledge of analytical techniques for the detection of pesticide levels and the subsequent assessment of nonoccupational human exposure.

Simultaneous determination and dietary risk assessment of clethodim and its metabolites in different fruits and vegetables

Clethodim is one of the most widely used herbicides in agriculture and, after field application, is metabolised to several metabolites. The potential toxicological negative effects of these compounds are poorly understood. Thus, recently, within the risk assessment framework, the European Food Safety Authority (EFSA) proposed to include the minor metabolites in the definition of clethodim residue. In this work, an easy to use and reliable UHPLC method coupled with a triple quadrupole MS/MS was developed and validated for the detection and quantification of the herbicide clethodim and related metabolites clethodim sulphone, clethodim sulphoxide, metabolites M17R and M18R in apple, grape, olive and rice. The five analytes were extracted by using a modified QuEChERS procedure, while the active ingredients were determined in multiple reaction monitoring (MRM) ion-switching mode. The proposed method showed calibration curve linearity with r² ≥ 0.990 for all active ingredients (a.is.) both in solvent and matrix extracts. Limits of quantitation (LOQ) of the five compounds ranged from 9.44 µg/kg for M17R in olive extract to 11.01 µg/kg for clethodim in apple extract. Recoveries values ranged from 86% to 119% at two concentration levels (LOQ and 10xLOQ), while the intraday and interday precisions of the method were both below 10% in all cases. The method was successfully used for the quantification of the five a.is. in different food matrices. Furthermore, chronic dietary risk was investigated using a hazard quotients (HQ) method based on European dietary habits. The chronic dietary exposure risk quotients ranged from 1.0 × 10^-5 (lower bound scenario) to 2.7 × 10^-4 (upper bound scenario) which were significantly lower than 1. Data obtained indicate that the dietary exposure risks were acceptable for clethodim and its major and minor metabolites applied in apple, table grape, rice and table olive.

Simultaneous determination of the herbicide bixlozone and its metabolites in plant and animal samples by liquid chromatography-tandem mass spectrometry

Tracing the herbicide bixlozone and its metabolites in food is necessary to assess their risks to human health. In the study, a rapid and effective analytical method using the quick, easy, cheap, effective, rugged, and safe method for the simultaneous determination of bixlozone and its metabolites (2,4-dichlorobenzoic acid, 3-hydroxy-propanamide-bixlozone, and 5'-hydroxy-bixlozone) in plant and animal samples (tomato, cucumber, apple, wheat flour, meat, milk, and egg) was developed based on ultra high performance liquid chromatography-tandem mass spectrometry. The method was validated based on the linearity (R²  > 0.99), sensitivity (limit of quantification = 0.01 mg/kg), recovery (70.2-115.1%), and precision (intraday 1.2-17.6%, interday 0.3-16.0%). Detection was achieved within 6.0 min. The method is reliable for the determination of four target compounds in all seven matrices. The satisfactory validation criteria and successful application show that the proposed methodology is suitable for the detection of four target compounds in real matrices.