Residue distribution and risk assessment of bifenazate and its metabolite in garlic plant.

The dissipation, conversion and risk assessment of bifenazate and bifenazate-diazene in garlic plant were studied by a modified QuEChERS method coupled with UHPLC-MS/MS for the first time. Bifenazate dissipated rapidly in garlic chive and serpent garlic with the half-lives of 3.0-3.9 days and 6.1-6.9 days, respectively. Bifenazate residue on garlic (<0.01 mg/kg) was significantly lower than the other two matrices in the whole growing period, which meant residues in the above-ground part were not transferred to the garlic. Furthermore, garlic chive had higher residues than serpent garlic due to the differences in morphological characteristics. Bifenazate-diazene was easier to convert to bifenazate, with the conversion rates of 93%, 16% and 32% in garlic, serpent garlic and garlic chive extracts, respectively. Additionally, the dietary intake risk for bifenazate was acceptable with RQchronic < 100% according to the international and national assessments.

Residue dissipation and dietary exposure risk assessment of methoxyfenozide in cauliflower and tea via modified QuEChERS using UPLC/MS/MS.

BACKGROUND: Methoxyfenozide possesses efficacy against a variety of lepidopteron pests, including the major pests in cauliflower and tea, so it is of great importance to generalize the practical use of methoxyfenozide in the field. RESULTS: An efficient method was developed and validated in both vegetable matrix and extract-rich matrix (cauliflower and tea) using modified QuEChERS combined with UPLC/MS/MS analysis. The recoveries in cauliflower, made tea and tea shoots ranged from 94.5 to 108.0%, from 85.0 to 91.6% and from 77.3 to 82.0% respectively, with relative standard deviations (RSDs) below 17.3% in all cases. The field results showed that methoxyfenozide dissipated in cauliflower with half-life (t1/2 ) at 2.5-3.5 days and in tea with t1/2 at 1.2 days. Combining the above experimental data and statistical food intake values, the risk quotient (RQ) values were significantly lower than 1. CONCLUSION: The quantification method of methoxyfenozide in cauliflower or tea has not been established until this study. The dissipation and dietary exposure risk assessment of methoxyfenozide in cauliflower and tea were investigated in the field. Methoxyfenozide dissipated rapidly in cauliflower despite different climates, and it dissipated faster in tea. The dietary risk of methoxyfenozide through cauliflower or tea was negligible to humans. This study not only provides guidance for the safe use of methoxyfenozide but also serves as a reference for the establishment of maximum residue limits (MRLs) in China. © 2019 Society of Chemical Industry.

Determination, residue analysis, risk assessment and processing factors of tebufenozide in okra fruits under field conditions.

BACKGROUND: Ensuring the yield, quality, and profitability of okra by preventing and controlling pests with the application of insecticides has increased in the last decade. Some insecticide residues might remain in edible parts of okra (fruits) and lead to several potential human health problems. Therefore, research on the residue behaviour, risk assessment and removal approach of insecticides on okra fruits is important for food safety, together with the proper application and residual elimination of insecticides in okra. RESULTS: A simple liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was established and validated for determining the tebufenozide residues in okra fruits. The recoveries of tebufenozide in okra fruits were >72% with relative standard deviations of 0.6 to 6.1%. The dissipation rates of tebufenozide were different in okra fruits cultivated under open land and glasshouse field conditions because of the discriminating humidity and temperature conditions. The dietary intake of the tebufenozide residues from okra fruit consumption for Chinese consumers was fairly low, with approximately no potential health risk. The processing factor values of washing, blanching, washing + blanching and soaking were all less than one, which indicated that these processes could effectively reduce the residual hydrazide in the okra fruit. CONCLUSION: The developed method for analysing tebufenozide in okra fruits was applicable for field studies on this insecticide. The potential health risk of tebufenozide in okra fruits could be negligible to the health of different age groups of Chinese consumers. The soaking process effectively removed tebufenozide residues from okra fruits. The obtained data will help Chinese governments establish a maximum residue limit of tebufenozide in okra and provide data for the risk assessment and removal of tebufenozide in other crops. © 2019 Society of Chemical Industry.

Assessment of anti-diabetic activity of a novel hydrazine-thiazole derivative: in vitro and in vivo method

Diabetes mellitus is a chronic disease resulting in oxidative stress that promotes tissue damage. The appearance of this disease is highly related to lifestyle and food of the population, being of great interest to search for a dietary supplement that can also act by reducing oxidative alterations. Based on the broad range of biological activity of thiazole derivatives, this work aimed to evaluate the in vitro antioxidant activity of a novel hydrazine-thiazole derivative and studies in vivo. In in vivo experiments, the liver extracts of healthy and diabetic Wistar rats were used, with analysis to determine the enzymatic activity of SOD, CAT, GPx, and GR, and determination of lipid peroxidation. Finally, in the blood of these animals, biochemical parameters were evaluated. Statistical evidence of changes caused in liver enzymes and liquid peroxidation was not detected; however, these parameters were also not changed between control groups with and without diabetes. On the other hand, concerning biochemical parameters, significant differences were detected in uric acid, alkaline phosphatase, ALT, and urea, indicating a possible antioxidant protective role of such substances in the liver and kidney of diabetic animals that could be acting by means other than that commonly reported in the literature.

Residue analysis and dietary exposure risk assessment of tebufenozide in stem lettuce (Lactuca sativa L. var. angustana Irish).

Tebufenozide, a newly-developed nonsteroidal ecdysone agonist, is in pre-regulation phase (before approval for use) on stem lettuce in China. Aiming at the safe application of tebufenozide, the dissipation and terminal residue trials on stem lettuce were performed under good agricultural practice (GAP). The dissipation trials shown that tebufenozide was rapidly degraded in stem lettuce, with half-lives of 5.0-8.2 days. Pre-regulation dietary exposure risk assessments were evaluated to recommend maximum residue limits (MRLs) based on risk quotients (RQ) method. Relevant toxicological parameters including ADI (acceptable daily intake) and ARfD (acute reference dose) were applied to assess the potential dietary exposure risk. The results indicated the chronic dietary exposure risk probability (RQc) of tebufenozide ranged from 36.4% to 70.0%. The acute dietary exposure risk probability (RQa) of tebufenozide was 2.88%-8.49% in lettuce stems and 14.0%-20.0% in lettuce leaves, respectively. On the basis of supervised field trial data and dietary exposure risk assessment results, the MRLs of tebufenozide were recommended as 3 mg/kg for lettuce stems and 10 mg/kg for lettuce leaves, respectively. The results demonstrated that the dietary exposure risk of tebufenozide used in stem lettuce under GAP was negligible and would not pose unacceptable health risk to Chinese consumers.

Safety assessment of chromafenozide residue level with decline study on tomato in Egypt.

The objective of this study is to perform a safety assessment of chromafenozide residue level on tomato at the Egyptian national level. An open field decline study of chromafenozide on tomato was performed. The theoretical maximum daily intake (TMDI) of chromafenozide was calculated for assessing the chronic dietary exposure indicating that the ADI value of chromafenozide (0.27 mg/kg bw/day) was not exceeded. As a result, the safety assessment of chromafenozide residue levels was attained. A validated method of the QuEChERS approach followed by HPLC-DAD analysis was used to determine the chromafenozide residues. The recoveries ranged from 70 to 88% with relative standard deviations ranging from 2.0 to 9.0%. The limit of quantitation was 0.01 mg/kg. The half-life of chromafenozide on tomatoes was 3.5 days.

Residue analysis of four diacylhydrazine insecticides in fruits and vegetables by Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method using ultra-performance liquid chromatography coupled to tandem mass spectrometry.

The new analytical method using Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) procedure for simultaneous determination of diacylhydrazine insecticide residues in fruits and vegetables was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The four insecticides (tebufenozide, methoxfenozide, chromafenozide, and halofenozide) were extracted from six fruit and vegetable matrices using acetonitrile and subsequently cleaned up using primary secondary amine (PSA) or octadecylsilane (C18) as sorbent prior to UPLC-MS/MS analysis. The determination of the target compounds was achieved in less than 3.0 min using an electrospray ionization source in positive mode (ESI+) for tebufenozide, methoxfenozide, and halofenozide and in negative mode (ESI-) for chromafenozide. The limits of detection were below 0.6 µg kg(-1), while the limit of quantification did not exceed 2 µg kg(-1) in different matrices. The QuEChERS procedure by using two sorbents (PSA and C18) and the matrix-matched standards gave satisfactory recoveries and relative standard deviation (RSD) values in different matrices at four spiked levels (0.01, 0.05, 0.1, and 1 mg kg(-1)). The overall average recoveries for this method in apple, grape, cucumber, tomato, cabbage, and spinach at four levels ranged from 74.2% to 112.5% with RSDs in the range of 1.4-13.8% (n = 5) for all analytes. This study provides a theoretical basis for China to draw up maximum residue limits and analytical method for diacylhydrazine insecticide in vegetables and fruits.

Determination of biotin following derivatization with 2-nitrophenylhydrazine by high-performance liquid chromatography with on-line UV detection and electrospray-ionization mass spectrometry.

Currently, biotin is typically determined in Japan using a microbiological method. Such microbiological assays are sensitive, but they are not always highly specific and are also rather tedious and time-consuming. In the present study, RP-HPLC and LC-MS methods for the determination of biotin have been developed by derivatizing the carboxyl group with 2-nitrophenylhydrazine hydrochloride. 2-Nitrophenylhydrazine is used for the derivatization of carboxylic acids, and these derivatives are known to be applicable to LC-MS detection. Biotin in tablets were extracted by the addition of water and ultrasonic agitation. In order to clean up the sample solution, the filtrate was applied to an ODS cartridge and eluted with methanol. The conditions for preparing the 2-nitrophenylhydrazide derivatives were modified from a previous report for fatty acids. Good recovery rates of over 70% were obtained for the addition of 5-125 microg of biotin per formulation. The detection limit in HPLC at 400 nm was 0.6 ng per injection, with good linearity being obtained over the concentration range 0.001-0.2 microg per injection. Further, derivatives were determined by LC-MS with electrospray ionization, where the spectra indicated the molecular ions [M+H](+). The detection limit was 0.025 ng per injection in the selected ion monitoring analysis, and linearity was observed in the range of 0.6-6 ng per injection. The proposed method could be used to specifically determine the presence of biotin in relatively clean samples.

Gyromitra esculenta mushroom: a comparative assessment of its carcinogenic potency.

A comparative assessment is performed on one of the false morel mushrooms, Gyromitra esculenta, including the amounts of some hydrazines present in this fungus, the cancer-inducing doses of these chemicals or the mushroom used in animal experiments, the total amounts of the hydrazines or mushroom needed to induce neoplasms in mice and the estimated total amounts of hydrazines or mushroom needed to induce cancer in humans. When one compares the estimated amounts of hydrazines required to induce cancer with the amount of raw Gyromitra esculenta needed to yield a similar effect, it becomes clear that to date 37 percent of the carcinogenic ingredients of this fungus have been identified.