Simultaneous determination and risk assessment of metalaxyl and azoxystrobin in potato by liquid chromatography with tandem mass spectrometry

Abstract

A liquid chromatography with tandem mass spectrometry method was developed and validated to simultaneously determine metalaxyl and azoxystrobin in soil, potato, and potato foliage samples. The samples were extracted by 20 mL of acetonitrile and purified with dispersive solid-phase extraction using octadecyl silane as sorbent. The method showed good linearity (determination coefficients ≥ 0.9926) for metalaxyl (2.5-500 ng/mL) and azoxystrobin (5-1000 ng/mL). The limits of detection and quantification for both fungicides were 1.5-20 μg/kg. The average recoveries in soil, potato, and potato foliage were 83.07-92.87% for metalaxyl and 82.71-98.53% for azoxystrobin. The intra- and inter-day relative standard deviations were all less than 9%. The method was successfully applied on the residual analysis of metalaxyl and azoxystrobin in field trial samples. The results showed that the concentrations of metalaxyl and azoxystrobin in potato samples collected from Guizhou and Hunan were below 50 and 100 μg/kg (maximum residue limit set by China), respectively, at 5 days after the last application. When following the recommended application manual, metalaxyl and azoxystrobin do not present health concerns to the population because the risk quotients are far below 100%. All the above data could help and promote the safe and proper use of metalaxyl and azoxystrobin in potato.

A liquid chromatography–tandem mass spectrometry method to simultaneously determinate dichlorvos and phoxim in tobacco

“…An analysis of variance (ANOVA) statistical analysis (Nie et al, ; Yu et al, ) was used to evaluate the determination of dichlorvos and phoxim in soil, green tobacco leaves and cured tobacco leaves. Different extraction solvents, volumes of extractants, extraction methods and sorbents were investigated to identify the optimum sample extraction and purification conditions and the elements with a significant impact on the analysis of both insecticides.…”

“…An analysis of variance (ANOVA) statistical analysis (Nie et al, 2015;Yu et al, 2018) was used to evaluate the determination of dichlorvos and phoxim in soil, green tobacco leaves and cured tobacco leaves.…”

A novel validated simple derivatization liquid chromatographic method with diode array detection for the simultaneous determination of mancozeb, azoxystrobin and difenoconazole in pesticide dosage form

“…For the determination of mancozeb by iodometry, 12 square-wave adsorptive stripping voltammetry (SWAdSV), 13,14 batch injection analysis (BIA) with pulsed amperometric detection (PAD) on boron-doped diamond (BDD) electrode, 15 UV-spectrophotometry, 16–20 flow injection (FI) spectrophotometry, 21,22 photoacoustic and Fourier transform infrared spectroscopy, 23,24 gas chromatography (GLC) with specific detectors such as an electron capture detector (ECD), flame atomic absorption spectroscopic detector (FAAS) and flame photometric detector (FPD), 25,26 high performance liquid chromatography (HPLC), 27–35 gas chromatography-mass spectrometry (GC-MS), 36–42 and liquid chromatography-mass spectrometry (LC-MS) 43–49 methods have been reported. Similarly, various analytical methods for the quantification of azoxystrobin using UV-spectrophotometry, 50 flow injection chemiluminescence (FI-CL), 51 gas chromatography (GLC), 52–58 high-performance liquid chromatography (HPLC), 59–68 gas chromatography-mass spectrometry (GC-MS) 69–71 and liquid chromatography-mass spectrometry (LC-MS) 72–74 for single and multipesticide formulations were reported in literature. Furthermore, several methods for the quantification of Difenoconazole using voltammetric and flow amperometric detection on a boron-doped diamond electrode (FIA-ED), 75 UV-spectrophotometry, 76 gas chromatography (GLC), 77–83 high-performance liquid chromatography(HPLC), 84–87 gas chromatography-mass spectrometry (GC-MS) 88–92 and liquid chromatography-mass spectrometry (LC-MS) 93–99 methods were repored.…”

The Study of the Kinetics of Metalaxyl Accumulation and Dissipation in Durian (Durio zibethinus L.) Leaf Using High-Performance Liquid Chromatography (HPLC) Technique

“…To reduce the risk of metalaxyl overuse, more information about metalaxyl residue and efficacy inside durian plants is required. Analytical methods to detect metalaxyl residue in other plants had been previously reported, such as high-performance liquid chromatography (HPLC) [13][14][15][16], ultra-performance liquid chromatography (UPLC) [17], liquid chromatography tandem mass spectrometry (LC-MS/MS) [18][19][20], high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) [21], and gas chromatography (GC) [22]. The dissipation patterns of metalaxyl were studied in grape, pepper, potato, tomato, cucumber, and Swiss chard plants [13,14,16,18,21] with the half-life ranging from 0.4-6.0 days.…”