Dissipation, Processing Factors and Dietary Risk Assessment for Flupyradifurone Residues in Ginseng.

The massive use of pesticides has brought great risks to food and environmental safety. It is necessary to develop reliable analytical methods and evaluate risks through monitoring studies. Here, a method was used for the simultaneous determination of flupyradifurone (FPF) and its two metabolites in fresh ginseng, dried ginseng, ginseng plants, and soil. The method exhibited good accuracy (recoveries of 72.8-97.5%) and precision (relative standard deviations of 1.1-8.5%). The field experiments demonstrated that FPF had half-lives of 4.5-7.9 d and 10.0-16.9 d in ginseng plants and soil, respectively. The concentrations of total terminal residues in soil, ginseng plants, dried ginseng, and ginseng were less than 0.516, 2.623, 2.363, and 0.641 mg/kg, respectively. Based on these results, the soil environmental risk assessment shows that the environmental risk of FPF to soil organisms is acceptable. The processing factors for FPF residues in ginseng were 3.82-4.59, indicating that the concentration of residues increased in ginseng after drying. A dietary risk assessment showed that the risk of FPF residues from long-term and short-term dietary exposures to global consumers were 0.1-0.4% and 12.07-13.16%, respectively, indicating that the application of FPF to ginseng at the recommended dose does not pose a significant risk to consumers.

Dissipation and residue analysis of novel nematicide trifluorocide in ginseng and soil using modified QuEChERS method coupled with HPLC-MS/MS.

In the present study, an analytical method that combined a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and high-performance liquid chromatography coupled with tandem mass spectrometry was developed to determine trifluorocide in fresh and dried ginseng roots, plants (stems and leaves), and soil. At three spiked levels (0.01, 0.1, and 1.0 mg kg-1), the mean recoveries (n = 15) of trifluorocide from fresh and dried ginseng roots, plants, and soil were in the range of 95.6 - 109.7%, with relative standard deviations less than 10.0%. The limits of quantitation of different matrices were determined to be 0.01 mg kg-1. Dissipation and residue study of trifluorocide was conducted in ginseng cultivation ecosystems in Northeast China. The t1/2 (half-life) of trifluorocide in ginseng fresh roots, plants, and soil were 8.3-13.1 days, 7.4-10.9 days, and 8.8-10.6 days, respectively. The terminal residues of trifluorocide in ginseng fresh roots were less than 0.01 mg kg-1 after 35 days of trifluorocide application. This study could be beneficial in residue analysis and assist in the scientific application of trifluorocide during ginseng cultivation.

Rapid Determination of 21 Chinese Domestically Registered Pesticides in Ginseng Using Cleanup Based on Zirconium-Oxide-Modified Silica and Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry.

In this study, an analytical method was developed for the rapid determination of 21 pesticides used in ginseng cultivation. All pesticides covered by this method have been registered by 2020 in China for use on ginseng. The extracts were cleaned up using zirconium-oxide-modified silica (Z-Sep) and primary secondary amine (PSA). The combination of Z-Sep and PSA provided good recovery for all analytes and the cleanest matrix background out of a number of PSA-based sorbent combinations, as indicated by high-performance liquid chromatography (HPLC) and gas chromatography (GC). Instrumental analysis was completed in 5 min using the ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The linearity (r > 0.99) for all analytes was satisfactory over the calibration range of 0.002-0.1 µg mL-1. Intraday recoveries (n = 5) at ginseng-spiked levels of 0.02, 0.05, 0.1, and 1 mg kg-1 ranged between 72% and 119%, with the corresponding relative standard deviations (RSDs), were less than 19%, while the interday recoveries (n = 15) ranged between 77% and 103%, and RSDs were less than 22%. Limits of quantitation (LOQs) ranged between 0.02 and 0.05 mg kg-1 for all 21 pesticides. This is a seminal study using Z-Sep for the efficient cleanup of ginseng samples, and it could present a practical method for future monitoring of pesticide residues in ginseng produced in China.

Dissipation and residues of dimethyl disulfide in tomatoes and soil under greenhouse and open field conditions.

Tomatoes have been widely planted in greenhouses and fields in China. Soil-borne diseases are more harmful to tomatoes than other types of diseases. Dimethyl disulfide (DMDS) was used as a novel fumigant instead of methyl bromide to control soil-borne diseases. To assess the safety of DMDS for use on tomatoes, its dissipation and terminal residues were investigated at three different locations under greenhouse and open field conditions. The QuEChERS method was simplified using gas chromatography with mass spectrometry detection and combined with liquid-liquid extraction purification to allow determination of DMDS levels in both the tomatoes and the soil. The average recovery of the method was between 85.3 and 98.6%, with the relative standard deviation (RSD) ranging from to 1.9-10.3%. The dissipation and terminal residues of DMDS in the tomatoes and the soil were analyzed using the method, the results of which showed that the half-life of DMDS ranged from 0.3-6.5 d in the soil at three different locations. The terminal residues of DMDS in the tomatoes and the soil were not detected. This study provided data that the Chinese government can use to support appropriate and safe guidance for the use of DMDS on agriculture.

Residue analysis of fungicides fenpicoxamid, isofetamid, and mandestrobin in cereals using zirconium oxide disposable pipette extraction clean-up and ultrahigh-performance liquid chromatography-tandem mass spectrometry.

In the present study, a fast multiresidue method determining three novel fungicides fenpicoxamid, isofetamid, and mandestrobin in cereals was developed and validated for the first time using ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Samples were extracted by QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology, and cleaned up using the disposable pipette extraction (DPX) tips containing primary secondary amine (PSA) and silica gel modified with zirconium oxide (Z-Sep) in less than 1 min. Linearity (r > 0.99) of three fungicides in the calibration range of 0.001-0.1 µg mL-1 was satisfactory. Mean recoveries (n = 15) from all matrices were between 84.8% and 100.3% as the corresponding intra-day and inter-day relative standard deviations (RSDs) were less than 10.6%. Limits of quantitation (LOQs) of all analytes in different matrices were defined at 0.01 mg kg-1. The results indicate this method can serve as a sensitive and rapid approach to monitoring contents of fenpicoxamid, isofetamid, and mandestrobin in cereals.

Determination of the Novel Insecticide Flupyradifurone and Its Two Metabolites in Traditional Chinese Herbal Medicines Using Modified QuEChERS and High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

In this study, an analytical method for the simultaneous determination of the novel insecticide flupyradifurone and its two metabolites in a variety of traditional Chinese herbal medicines was developed for the first time using high-performance liquid chromatography-tandem mass spectrometry. A simple and efficient method using dispersive solid-phase extraction was employed for the pretreatment of the samples. Several extractions and cleanup strategies were evaluated. The recoveries (n = 15) of flupyradifurone and its metabolites at three spiking levels were in the range 71.3%-101.7%, with corresponding intraday and interday relative standard deviations of 1.1%-14.8%. The limits of quantitation were 0.01 mg/kg for flupyradifurone and 0.1 mg/kg for its two metabolites. Overall, our developed method was sensitive and reliable for the fast screening of flupyradifurone and its two metabolites in traditional Chinese herbal medicine samples.

Simultaneous Determination of Five Diamide Insecticides in Food Matrices Using Carbon Nanotube Multiplug Filtration Cleanup and Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry.

In this study, an analytical method was developed and validated for simultaneous determination of five diamide insecticides (chlorantraniliprole, cyantraniliprole, flubendiamide, cyclaniliprole, and tetrachlorantraniliprole) in food matrices. Determination of the latter two diamide compounds is first reported. Samples were cleaned up by multiplug filters containing carbon nanotubes (CNT) or hydrophilic-lipophilic balanced copolymers (HLB) and classic dispersive solid phase extraction (d-SPE) procedures, respectively. The CNT multiplug filter performed the best in terms of process rapidity and cleanup efficiency; thus, it was finally chosen for sample cleanup. Instrumental analysis was completed in 5 min using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Mean recoveries of the five diamides ranged from 84.3 to 110.0%, with intraday and interday relative standard deviations (RSD) of less than 13.5%. Limits of quantitation (LOQ) of all analytes ranged from 0.005 to 0.01 mg kg-1 in different matrices. The results indicate this method is reliable for monitoring the five diamide insecticides in various foods.

Dissipation and residues of the diamide insecticide chlorantraniliprole in ginseng ecosystems under different cultivation environments.

Ginseng is a valuable herb, the roots of which have been consumed for medicinal use since ancient times in Asian countries. Currently, its cultivation in China is conducted in either forests or non-forest areas. In this study, we investigated the dissipation and residues of the diamide insecticide chlorantraniliprole (CAP) in ginseng ecosystems in these two cultivation environments. The half-life of CAP in ginseng leaves was calculated to be 16.5 days in non-forest areas and 23.9 days in forests, while the half-life of CAP in the soil under non-forest and forest cultivation was 33.0 and 53.3 days, respectively. The relatively long persistence of CAP in ginseng leaves and soil could be attributed to the unique cultivation techniques of ginseng, which prevents exposure to direct sunlight irradiation and rainfall. The residual amounts of CAP in ginseng leaves, roots, and soil in non-forest areas were 0.168, 0.011, and 0.013 mg kg-1 21 days after CAP application at the maximum label-allowed dosage and frequency versus 0.564, 0.013, and < 0.005 mg kg-1 in forests. CAP application strategies for the control of Lepidoptera pests such as armyworms, and the safety of harvested ginseng roots are recommended for ginseng cultivated in forests and non-forest areas based on the results of the CAP residue experiments.