The Analysis and Fate of the Fungicide Fenpropimorph and Its Degradation Product Fenpropimorphic Acid in Soil by Liquid Chromatography Mass Spectrometry

Abstract

This article describes a method for extraction of soil samples and analysis with liquid chromatography and mass spectrometric detection after atmospheric pressure chemical ionisation (APCI) of the fungicide fenpropimorph and its degradation product fenpropimorphic acid. The method gives high recovery rates (about 80 %) and detection limits below 1 μg/kg soil for both compounds. The article elucidates the difference between the parent compound and the degradation product with respect to adsorption properties, where fenpropimorph with a K_d value about 161 kg/L in a sandy loam is expected to be immobile in soil while the K_d value for fenpropimorphic acid is determined to 1.3 kg/L which means a much higher mobility.

Two studies on the degradation of fenpropimorph and occurrence of the degradation product are mentioned. The first experiment is a batch experiment where fenpropimorph is mixed with the soil while the second experiment is a field study with pesticide application in normal dosage and ten times normal dosage. Both experiments demonstrate the occurrence of the degradation product in the soil during months after application.     

Pentafluorobenzylation of the fungicide metabolite fenpropimorphic acid for GC/MS investigations of soil samples

For the determination of fenpropimorphic acid in soil samples, a derivatization step with pentafluorobenzylbromide has been established in order to perform GC/MS with negative chemical ionization. In spite of forming the electrophilic pentafluorobenzyl ester, only the fenpropimophic acid anion was detected. Additional derivatization reactions with diazomethane and 2,2,2-trichloroethanol showed that the formation of this acid anion was depending on the leaving group. In comparison with the determination of the methyl ester with GC/MS and electron impact ionization, the detection limit was however improved from 10 microg/kg to 2 microg/kg dry soil and the analytical quality was ensured due to higher stability of the pentafluorobenzyl ester standards.     

Pentafluorobenzylation of the fungicide metabolite fenpropimorphic acid for GC/MS investigations of soil samples

For the determination of fenpropimorphic acid in soil samples, a derivatization step with pentafluorobenzylbromide has been established in order to perform GC/MS with negative chemical ionization. In spite of forming the electrophilic pentafluorobenzyl ester, only the fenpropimophic acid anion was detected. Additional derivatization reactions with diazomethane and 2,2,2-trichloroethanol showed that the formation of this acid anion was depending on the leaving group. In comparison with the determination of the methyl ester with GC/MS and electron impact ionization, the detection limit was however improved from 10 g/kg to 2 g/kg dry soil and the analytical quality was ensured due to higher stability of the pentafluorobenzyl ester standards.     

Simultaneous determination of trifloxystrobin and trifloxystrobin acid residue in rice and soil by a modified quick,easy, cheap,effective, rugged,and safe method using ultra high performance liquid chromatography with tandem mass spectrometry

A sensitive analytical method for the simultaneous determination of trifloxystrobin and its metabolite trifloxystrobin acid in rice including straw, bran, brown rice and soil was developed by using ultra high performance liquid chromatography coupled with tandem mass spectrometry. The fungicide trifloxystrobin and its metabolite trifloxystrobin acid were extracted using acetonitrile with 1% formic acid v/v and subsequently cleaned up by primary secondary amine, octadecylsilane or graphitized carbon black prior to ultra high performance liquid chromatography coupled with tandem mass spectrometry. The determination of two target compounds was achieved in less than 3 min using an electrospray ionization source in positive mode. The limits of detection were below 0.22 μg/kg and the limits of quantification did not exceed 0.74 μg/kg in all matrices, which were much lower than the maximum residue levels established by the Codex Alimentarius Commission. The overall average recoveries in four matrix at three levels (0.1, 1.0 and 5.0 mg/kg) ranged from 74.2 to 107.4% with a relative standard deviations of less than 7.8% (n = 5) for both analytes. The method was demonstrated to be convenient and reliable for the routine monitoring of trifloxystrobin and its metabolite. The developed method was validated and applied for the analysis of degradation study samples.     

Investigations on the substitution of dichloromethane in pesticide residue analysis of plant materials

According to the multiresidue analysis method DFG S 19, different approaches for the substitution of dichloromethane in the liquid/liquid partition step were investigated. Due to maximum residue limits (MRL), fortification experiments with 17 GC/ECD and GC/NPD detectable pesticides were carried out in concentrations of 1 and 0.1 mg/kg apples, 1 and 0.05 mg/kg tomatoes, 1 and 0.1 mg/kg lettuce, respectively. In supplementary greenhouse experiments, lettuce was cultivated and a mixture of 10 plant protection products was applied in commonly used amounts. In both cases, the comparison of pesticide recoveries shows that several less toxic solvents like cyclohexane, light petroleum and tertiary butyl methyl ether are suitable substitutes for the more toxic and persistent dichloromethane.     

Simultaneous Analysis of Fenpropimorph and Fenpropimorph Acid in Six Different Livestock Products Using a Single-Sample Preparation Method Followed by Liquid Chromatography–Tandem Mass Spectrometry

Pesticides in livestock products must be measured to ensure food safety. We developed a single-sample preparation method followed by liquid chromatography–tandem mass spectrometry (LC-MS/MS) for simultaneous determination of fenpropimorph and fenpropimorph acid in six different livestock products. The extraction method was a modification of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and was validated according to the CODEX guidelines. The matrix-matched calibration curves for fenpropimorph and fenpropimorph acid exhibited good linearity, with coefficients of determination (R² values) higher than 0.998. The limit of detection (LOD) and the limit of quantitation (LOQ) were 1.25 and 5.0 µg kg⁻¹, respectively. The average recovery values ranged from 61.5% to 97.1% for samples fortified to the LOQ, 2 × LOQ, and 10 × LOQ. The method fully complied with the CODEX guidelines and was successfully applied to real samples obtained from domestic markets.     

Simultaneous high-performance liquid chromatographic analysis of buspirone and its metabolite 1-(2-pyrimidinyl)-piperazine in plasma using electrochemical detection.

A selective and sensitive high-performance liquid chromatographic method with coulometric detection is described for the quantitation of buspirone and its active metabolite, 1-(2-pyrimidinyl)piperazine, in plasma samples of mice treated orally with buspirone (10 mg/kg body weight). The analytes are extracted with a carboxylic acid solid-phase extraction column before chromatography. A dual-electrode electrochemical detector is used. The limit of detection is 50 pg for buspirone and 35 pg for 1-(2-pyrimidinyl)piperazine.     

Quantification of veterinary antibiotics (sulfonamides and trimethoprim) in animal manure by liquid chromatography-mass spectrometry

A fast and cost effective method was developed to extract and quantify residues of veterinary antimicrobial agents (antibiotics) in animal manure by liquid-liquid extraction and liquid chromatography-mass spectrometry. The compounds investigated include six sulfonamides, one metabolite, and trimethoprim. The method was performed without sample clean up. Recoveries from spiked manure slurry samples (spike level = 1 mg/kg) were as follows: sulfaguanidine (52%), sulfadiazine (47%), sulfathiazole (64%), sulfamethazine (89%), its metabolite N4-acetyl-sulfamethazine (88%), sulfamethoxazole (84%), sulfadimethoxine (51%), and trimethoprim (64%). Relative standard deviations of the recoveries were less than 5% within the same day and less than 20% between days. The limit of quantification was below 0.1 mg/kg liquid manure slurry for all compounds and calibration curves obtained from extracts of spiked samples were linear up to a level of 5 mg/kg liquid manure, except for trimethoprim (0.01-0.5 mg/kg). Analysis of six grab samples taken in Switzerland from manure pits on farms where medicinal feed had been applied revealed total sulfonamide concentrations of up to 20 mg/kg liquid manure.     

High-performance liquid chromatography-diode array detection assay for the detection and quantification of the Beauveria metabolite oosporein from potato tubers

A high-performance liquid chromatography-diode array detection (HPLC-DAD) assay is described for the detection and quantification of the secreted Beauveria brongniartii metabolite oosporein from potato tubers. Analyte recovery was achieved with a Britton-Robinson buffer system at pH 5.5 diluted with methanol 3:7 (v/v) (BR5.5-MeOH). An internal standard protocol using 2-iodobenzoic acid was established to minimize analytical error. The resulting assay, using a binary solvent gradient with acidic modifiers and detecting the metabolite at 287 nm, showed a limit of detection (LOD) of 2.4 mg oosporein/kg potato tubers. The oosporein content of potato tuber samples obtained from a field trial using the biological pest control B. brongniartii formulation Melocont-Pilzgerste in up to five-fold higher doses (250 kg Melocont-Pilzgerste/ha) as recommended per year was found to be below the established LOD.     

Quantitation of trace components in liquid process streams by direct liquid sampling mass spectrometry

This paper describes the development of a liquid sampling approach for trace analysis by electron impact ionization magnetic sector mass spectrometry, with no chromatographic separation. Development of a liquid sample introduction interface based on the principle of Programmable Temperature Vaporizing (PTV) GC injection is shown. A univariate procedure for the analysis of trace (mg kg(-1)) propanoic acid in acetic acid was developed. Results from the laboratory-based analysis of acetic acid are presented and compared with conventional GC analysis. The detection limit was 16 mg l(-1) and the speed of analysis was employed to acquire 30 scans per minute thus reducing the confidence intervals of the results and potentially allowing production plants to run much closer to sales specifications. For the analysis of more complex samples where the analytes contained no unique ions, multivariate analysis was employed and up to three scans per minute were acquired. Results from the analysis of an ester for six trace impurities are shown. Calibration was by partial least squares regression. The detection limits for these components were 20-30 mg kg(-1), well within the required product specifications. The system proved to be robust and easy to operate, with analyses being carried out over a period of several months requiring no maintenance of the spectrometer and only cleaning of the injection liner of the PTV injector on a monthly basis.     

Analysis of dichloroacetic acid in rat blood and tissues by hydrophilic interaction liquid chromatography with tandem mass spectrometry

Dichloroacetic acid (DCA) is a compound found in chlorinated drinking water. In addition, the compound is a metabolite of several halogenated solvents, including trichloroethylene (TCE) and perchloroethylene (PCE). Exposure to DCA is of concern because high doses of the compound have been shown to cause cancer in laboratory animals. Dosages of TCE administered to animals in cancer studies are designed to elicit maximal DCA formation in vivo, whereas levels of DCA to which individuals are exposed in drinking water are very low. Analysis of DCA in biological samples has been quite challenging. Derivatizing reagents commonly used to convert DCA into a more volatile form for analysis by gas chromatography (GC) have been found to convert trichloroacetic acid (TCA), a major metabolite of TCE and PCE, into DCA. High-performance liquid chromatography (HPLC) analysis does not require derivatization of DCA and can thus avoid this problem. However, the most popular stationary phases in HPLC columns do not retain small, polar compounds such as DCA well. The liquid chromatography/tandem mass spectrometry (LC/MS/MS) method described in this paper uses hydrophilic interaction liquid chromatography (HILIC), a type of chromatography that is able to retain these small, polar compounds. Method validation was performed using the United States Food and Drug Administration (USFDA) and International Conference on Harmonziation (ICH) Guidance for Industry: Bioanalytical Method Validation as a guide. Levels of DCA found in rats dosed with 2 g/kg TCE were 17.2 ng/mL (liver), 262.4 ng/mL (kidney), 175.1 ng/mL (lung), and 39.5 ng/mL (blood).     

Determination of a metabolite of nifursol in foodstuffs of animal origin by liquid–liquid extraction and liquid chromatography with tandem mass spectrometry

An analytical method has been developed for the detection of a metabolite of nifursol, 3,5‐dinitrosalicylic acid hydrazide, in foodstuffs of animal origin (chicken liver, pork liver, lobster, shrimp, eel, sausage, and honey). The method combines liquid chromatography and tandem mass spectrometry with liquid–liquid extraction. Samples were hydrolyzed with hydrochloric acid and derivatized with 2‐nitrobenzaldehyde at 37°C for 16 h. The solutions of derivatives were adjusted to pH 7.0−7.5, and the metabolite was extracted with ethyl acetate. 3,5‐Dinitrosalicylic acid hydrazide determination was performed in the negative electrospray ionization method. Both isotope‐labeled internal standard and matrix‐matched calibration solutions were used to correct the matrix effects. Limits of quantification were 0.5 μg/kg for all samples. The average recoveries, measured at three concentration levels (0.5, 2.0, and 10 μg/kg) were in the range of 75.8–108.4% with relative standard deviations below 9.8%. The developed method exhibits a high sensitivity and selectivity for the routine determination and confirmation of the presence of a metabolite of nifursol in foodstuffs of animal origin.     

Assay for codeine, morphine and ten potential urinary metabolites by gas chromatography--mass fragmentography

A mass fragmentography (MF) assay is described for ten potential, minor urinary metabolites of codeine (C) and morphine (M). Samples were hydrolyzed, extracted, derivatized with Tri-Sil Z and analyzed by methane chemical ionization (CI)-MF. The method is sensitive to ca. 0.01 microgram/ml for all compounds with the exception of normorphine (NM) which was difficult to extract with chloroform. The sensitivity of the MF assay for NM was only ca. 0.10 microgram/ml. Various solvent systems were investigated for optimization of extraction efficiency of all metabolites. A separate method for the extraction of NM is reported which utilizes a solid buffer--solvent combination, i.e., potassium carbonate--isopropanol. This latter method provided the best overall recovery of NM (39.0 +/- 3.4%). Gas chromatographic (GC) retention times of C, M and metabolites are reported for three liquid phases (3%) on Gas-Chrom Q (100-120 mesh). Resolution of metabolites (as trisilyl derivatives) was best on Silar-5CP and this phase was used in metabolic studies of C and M. GC resolution was not complete for all compounds; however, selection of specific ions for monitoring by MF provided the required specificity for all compounds except the 6 alpha- and 6 beta-hydroxy isomers. CI spectra for all metabolites are reported. The MF assay was used for urinary analysis of samples from guinea pigs that received single doses of C (15 mg/kg) or M (8 mg/kg). Following C administration 6 alpha- and 6 beta-hydrocodol, 6 alpha, beta-hydromorphol (undifferentiated), HM and M were measured. Following M administration only 6 alpha, beta-hydromorphol was found. The amount of total metabolite as percent dose for each component was calculated as less than 1%.     

The High-Pressure Liquid Chromatographic Determination of Chlordiazepoxide and Its N-Demethyl Metabolite in Mouse Brain

Abstract

This report presents a simple and accurate method for the analyses of chlordiazepoxide and its N-demethyl metabolite in small tissue samples such as mouse brains. The procedure involves the addition of diazepam as the internal standard, homogenization of the mixture with 0.01 N NaOH, and extraction with heptane containing 1.5% (v/v) iso-amyl alcohol. After evaporation of the organic solvent, the residue is dissolved in methanol and the compounds separated by reverse phase high pressure liquid chromatography with 66% (v/v) methanol in water as eluant in isocratic conditions. The analysis is linear for concentrations ranging from 0.5 to 50 ng/mg brain for chlordiazepoxide and the metabolite. The method was applied to the study of the distribution of chlordiazepoxide and the N-demethyl metabolite to the brain of mice receiving intraperitoneally 10 mg/kg chlordiazepoxide HCl.     

Effective high-performance liquid chromatographic determination of glafenine in plasma: pharmacokinetic application

A high-performance liquid chromatographic method for an effective determination of glafenine and its main metabolite, glafenic acid, is described. The assay involves separate extraction procedures for glafenine and for its metabolite, but the same internal standard (floctafenine) and the same chromatographic conditions (including a 5-micron C8 column, a quaternary solvent mixture of water-acetonitrile-diethylamine-acetic acid and an ultraviolet detector set at 360 nm). For 1 ml of plasma, the detection limit is 0.05 mg/l for glafenine and 0.25 mg/l for glafenic acid. Compared with previously described techniques, this assay uses a very low glafenine linearity range, which allows the true pharmacokinetics of this drug to be described for the first time.     

Surface-activated chemical ionization ion trap mass spectrometry for the analysis of cocaine and benzoylecgonine in hair after extraction and sample dilution

Surface-activated chemical ionization (SACI) was employed for the analysis of cocaine and its metabolite, benzoylecgonine, extracted from hair. Following decontamination and acid hydrolysis procedures on the hair sample, the sample solution was diluted (1:10) and directly analyzed by liquid chromatography/surface-activated chemical ionization multiple collisional stage single reaction monitoring mass spectrometry (LC/SACI-MS(3)-SRM) without solid-phase extraction (SPE) pre-purification and concentration procedures. To increase the selectivity of the method, MS(3) was chosen instead of the less selective MS/MS. This data was compared with that achieved using gas chromatography/mass spectrometry (GC/MS), the reference method used by the Italian Government Institute of Health protocol. The limits of detection (LODs) were 0.003 ng/(mg hair) for cocaine and 0.02 ng/(mg hair) for benzoylecgonine and the limits of quantitation (LOQs) were 0.01 ng/(mg hair) for cocaine and 0.04 ng/(mg hair) for benzoylecgonine. The squared correlation coefficient (R(2)) of the calibration curve was 0.9887-0.9980 for cocaine and 0.9987-0.9997 for benzoylecgonine. The percent accuracy error was 2-5% for both cocaine and benzoylecgonine using the LC/SACI-MS(3)-SRM approach, whereas it was higher for benzoylecgonine (20-25%) using the LC/SACI-MS/MS-SRM approach compared with the GC/MS data due to hair matrix contamination. In both cases, high precision was achieved (1-3% precision error), which confirmed the stability of the developed methods.     

Residue analysis of kresoxim‐methyl and boscalid in fruits,vegetables and soil using liquid–liquid extraction and gas chromatography–mass spectrometry

A GC‐MS procedure for simultaneously determining and validating kresoxim‐methyl and boscalid has been developed in fruit, vegetable and soil matrices. The method was based on one‐step liquid–liquid extraction with acetone and dichloromethane solvents. Estimated limits of detection (LODs) for kresoxim‐methyl and boscalid were 0.006 and 0.015 mg/kg, and limits of quantification (LOQs) were 0.02 and 0.05 mg/kg, respectively. The intra‐ and inter‐ precision were achieved with RSD better than 13.8 and 14.5%, and recoveries were in the range of 77.1–98.7% for kresoxim‐methyl and 72.8–105.1% for boscalid. The expanded uncertainties calculated at 0.1 mg/kg were below 18%. Concentration levels for residues of the two fungicides in melon samples from field trials collected 7 days after the last application were clearly below the established MRL values. Copyright © 2009 John Wiley & Sons, Ltd.     

三岛柴胡种子化学成分分析

应用ＧＣ／ＭＳ技术对云南省文山县引种的日本三岛柴胡种子的挥发油和脂肪酸成分进行定性定量分析,检出５３个挥发油成分和２８个脂肪酸成分,挥发油以４,４,５－三甲基－２－乙烯、２,２,４－三甲基－３－戊烯－１－醇、２,３－二甲基丁烯－３－二甲基戊烷为主;脂肪酸以十八碳烯酸,十八烷酸,壬二酸和辛二酸为主。从种子的正丁醇提取部分还分离出８个皂甙,其中３个鉴定为柴胡皂甙ｄ,ｃ和６″－Ｏ－乙酰基柴胡皂甙ｄ。     

Determination of polar organophosphorus pesticides in vegetables and fruits using liquid chromatography with tandem mass spectrometry: selection of extraction solvent

A method based on liquid chromatography (LC)-mass spectrometry (MS)/MS was developed for sensitive determination of a number of less gas chromatography (GC)-amenable organophosphorus pesticides (OPs; acephate, methamidophos, monocrotophos, omethoate, oxydemeton-methyl and vamidothion) in cabbage and grapes. For extraction, several solvents were evaluated with respect to the possibility of direct injection, matrix-induced suppression or enhancement of response, and extraction efficiency. Overall, ethyl acetate was the most favourable solvent for extraction, although a solvent switch was required. For some pesticide/matrix combinations, reconstitution of the residue after evaporation required special attention. Extracts were analysed on a C18 column with polar endcapping. The pesticides were ionised using atmospheric pressure chemical ionisation on a tandem mass spectrometer in multiple reaction monitoring mode. The final method is straightforward and involves extraction with ethyl acetate and a solvent switch to 0.1% acetic acid/water without further cleanup. The method was validated at the 0.01 and 0.5 mg/kg level, for both cabbage and grapes. Recoveries were between 80 and 101% with R.S.D. < 11% (n = 5). The limit of quantification was 0.01 mg/kg and limits of detection were between 0.001 and 0.004 mg/kg.     

Gas chromatographic-mass spectrometric determination of oxolinic acid in fish using selected ion monitoring

A gas chromatographic-mass spectrometric (GC-MS) method is described for the determination of oxolinic acid in fish tissues. oxolinic acid is reduced with sodium tetrahydroborate to permit GC analysis. The sample is homogenized with phosphate buffer (pH 6) and extracted with ethyl acetate. The extract is partitioned between sodium hydrogencarbonate solution and the aqueous phase is acidified and re-extracted with ethyl acetate. The residue from the ethyl acetate extract is dissolved in methanol and reduced with sodium tetrahydroborate. The reduction product is extracted with diethyl ether and analysed by GC-MS in the selected ion monitoring mode for the ions at m/z 204, 219 and 176. The detection limit is 0.001 mg/kg and the recoveries were 95.6% [relative standard deviation (R.S.D.) 7.7%] at 0.1 mg/kg and 72.9% (R.S.D. 13.3%) at 0.01 mg/kg fortification levels in fish.