Search

In this study, an efficient and fast method for the determination of the herbicide mesotrione and its two metabolites [4-methylsulfonyl-2-nitrobenzoic acid (MNBA) and 2-amino-4-methylsulfonylbenzoic acid (AMBA)] in rice, rice plants, rice hulls, water, and soil was developed, using ultra performance liquid chromatography coupled with tandem quadrupole (Xevo TQ-S) mass spectrometry (UPLC-Xevo TQ-S-MS/MS). The recoveries of the compounds were 68.6%–108.4% at different levels. The intra-day relative standard deviation (RSD) ranged from 2.0% to 14.4%, and the inter-day RSD, from 1.9% to 11.4%. The limits of quantification (LOQ) were ranged from 0.146 to 4.545 μg kg −1 for mesotrione, MNBA and AMBA. Dissipation and residual assays with the commercial formulation were conducted at three locations. The dissipation rates of the compounds were fast in rice plants, soil, and water, and residues at harvest were not detected in any of the three localities. [ABSTRACT FROM AUTHOR]

A simple residue analytical method based on the QuEChERS approach and high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection was developed for the analysis of fipronil and its three metabolites in cottonseed, cotton plant and soil. The average recoveries of four test compounds from all three matrices were 78.6–108.9% at the level of 0.005 to 0.5 mg/kg, with an RSD in the range of 0.6 to 13.7%. The limit of quantification (LOQ) of the four test compounds ranged from 0.005 to 0.01 mg/kg. The results of the residual dynamics experiments showed that fipronil dissipated rapidly in cotton plants and soil and that oxidation and photolysis were the main degradation pathways. Moreover, the bi-exponential models demonstrated a good fit of the measured data for fipronil in cotton plants and soil, with R2 in the range of 0.8989 to 0.9989. Furthermore, a total of 40 samples of cottonseed from Shandong Province were analyzed, and all of the samples were free from the four test compound residues. [ABSTRACT FROM AUTHOR]

An effective analytical method for the simultaneous determination of a novel insecticide flupyradifurone and its two metabolites was developed using ultra high performance liquid chromatography with tandem mass spectrometry coupled with a quick, easy, cheap, effective, rugged, and safe procedure. The three target compounds were extracted with acetonitrile and cleaned up with octadecylsilane, and were separated successfully between 1.9 and 3.1 min using an HSS T3 chromatographic column connected to an electrospray ionization source. All the matrix-matched samples at three fortified levels (0.01, 0.05, and 0.5 mg/kg) provided satisfactory recoveries in the range of 70.3-116.5% with relative standard deviations below 18.6%. The limits of quantitation were 10 μg/kg for flupyradifurone and difluoroethylamino-furanone and 100 μg/kg for 6-chloronicotinic acid. The limit of quantification of flupyradifurone was far below the maximum residue limit in the USA. The method is of great significance for establishing maximum residue limits in China. [ABSTRACT FROM AUTHOR]

A reliable and efficient method was firstly established for the simultaneous determination of saflufenacil and its metabolites (M800H02, M800H11 and M800H35) in cereals (soybean and corn) and fruits (apple, grape and orange), based on a triple quadrupole liquid chromatography mass spectrometer. The four target compounds were extracted with acetonitrile and purified by Florisil or Florisil with octadecylsilane from the cereals and fruits. Determination of the targets was achieved within 3.5 min by using Shim‐pack GIST C18 column connected to an electrospray ionization source (ESI‐ mode). The method showed excellent linearity (R2 > 0.9984), and the limits of quantitation were 1 µg/kg for all compounds. Average recoveries were in the range of 74.6%–108.1%, with an intra‐day relative standard deviation between 0.9% and 18.3%. The inter‐day relative standard deviation was less than 13.8%. The results demonstrate that this method is convenient for monitoring the residues of saflufenacil and its metabolites in food matrices. Practical applications: Saflufenacil controls many common annual broadleaf weed efficiently, it has been developed and launched into the market by domestic enterprises. Consequently, an analysis method for monitoring saflufenacil in food sample will be urgently needed in China over the next few years. This method provides separation with good specificity within 3.5 min, which is less than previous studies. For the five matrixes, the method presented satisfactory validation parameters in terms of good linearity, low limit of quantitations, and satisfactory accuracy and precision. Therefore, the method established in this study is a valuable tool to overcome gaps in determining saflufenacil and its metabolites in cereals and fruits, in order to accurate evaluation of risk and ensure food safety. [ABSTRACT FROM AUTHOR]

An efficient and sensitive analytical method for simultaneous determination of trace amounts of a new insecticide broflanilide and its metabolites (S(PFH‐OH)‐8007 and DM‐8007) residues in five typical Chinese soils (red soil, black soil, fluvo‐aquic soil, cinnamon soil and paddy soil) was developed. The samples were prepared by a modified quick, easy, cheap, effective, rugged, and safe method. The determination of broflanilide and its metabolites was conducted by ultra high performance liquid chromatography with tandem mass spectrometry with an electrospray ionization source in the positive ion mode. This is the first report for the determination of broflanilide and its metabolites in different soils. Broflanilide and its metabolites were extracted from all soils with acetonitrile and purified by a mixture of primary secondary amine and graphitized carbon black. The average recoveries of the three compounds in five types of soil ranged from 85.3 to 111.8% and the relative standard deviations were less than 13.6%. The limit of quantification was 0.1 μg/kg for all three compounds. This method was successfully used to determine broflanilide and its metabolites in five types of soil. The method was validated to be simple and effective for the determination of trace residual broflanilide and its metabolites in five types of soil. [ABSTRACT FROM AUTHOR]

Abstract: The dissipations of afidopyropen and its metabolite in wheat plant and soil were determined using a quick, easy, cheap, effective, rugged, and safe method with ultra‐high performance liquid chromatography and tandem mass spectrometry under a field ecosystem. The limits of quantification were estimated for both target compounds as 0.001 mg/kg. The recoveries of afidopyropen and its metabolite ranged from 94 to 114% (soil), 90 to 109% (wheat seed) and 81 to 91% (wheat straw) at levels of 0.001, 0.01, 0.1, and 2.0 mg/kg with relative standard deviations ≤7%. The results of the residual dynamics experiments showed that afidopyropen dissipated rapidly in wheat plant and soil. Its metabolite initially showed a tendency of rapid increase followed by a decrease in wheat plant but could not be detected in soil. The data showed that the first + first‐order model was more suitable for describing the decline of afidopyropen in wheat and soil. The half‐lives of afidopyropen in wheat plant and soil were 1.65 and 1.21 days, respectively. [ABSTRACT FROM AUTHOR]