ABSTRACT
This paper aims to establish a method for the determination of sulfur dioxide in sulfur fumigation Chinese herbs. Sample powder and hydrochloric acid solution were isolated by paraffin layer in order to avoid early reactions, with the generation of sulfur dioxide, headspace with airtight needle was used to transfer sulfur dioxide into gas chromatograph, and detected with thermal conductivity detector. The analytical performance was demonstrated by the analysis of 12 herbs, spiked at four concentration levels. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) within 15%, were obtained. The limit of detection (LOD) was below 10 mg x kg(-1). Standard addition can be used for low recovery samples. The method is simple, less time-consuming, specific and sensitive. Methods comparison revealed that gas chromatography is better than traditional titration in terms of method operability, accuracy and specificity, showing good application value.
ABSTRACT
AIM:To study a method for the determination of 13 N-methylcarbamate peticides in traditional Chinese herbal medicines(TCHMs).METHODS:Thirteen pesticides were extracted by acetonitrile,and purified through solid phase extraction(SPE)cartridges,then detected by HPLC with post-column derivatization and Fluorescense Detector excited wavelength was 330 nm,emissive wavelength was 465 nm.RESULTS:The analytical performance was demonstrated by the analysis of 6 TCHMs samples' extracts,spiked at three concentration levels for each pesticide.In general,the recoveries ranging from 74.1 to 108.8%,with relative standard deviations(RSDs)better than 15%,were obtained.The limit of quantification(LOD)of 13 pesticides from 0.000 3 to 0.06 mg/kg.CONCLUSION:The method has good extraction efficiency and purification effect,which could be standard of N-methylcarbamate peticides residues in the routine analysis of TCMs.
ABSTRACT
AIM: The multi-residues method was used to determine organophosphorus pesticides in traditional Chinese herbal medicines (TCHMs).METHODS: Fifty three pesticides were extracted by high-speed homogenization,and then cleaned sequentially by C_(18) and Carb/NH2 solid phase extraction (SPE) cartridges.The residues were simultaneously identified and quantified by GC-FPD equipped with dual tower,dual column and two FPD detectors.RESULTS: The analytical performance was demonstrated by the analysis of 6 TCHMs samples extracts,spiked at three concentration levels for each pesticide.In general,the recoveries ranging from 70% to 120%,with relative standard deviations (RSDs) less than 15%,were obtained.The limit of detection (LOD) for most of the targeted pesticides tested was below 0.01 mg/kg.CONCLUSION: The method has good extraction efficiency,purification effect and good reproducibility,which can be applied to the determination of organophosphorus pesticide residues in the routine analysis of TCHMs.
ABSTRACT
The paper is to report the establishment of a method for the determination of multi-residue organochlorine and pyrethroid pesticides in traditional Chinese medicines (TCMs). Fifty-six pesticides were extracted by high-speed homogenization, and then purified through gel permeation chromatography (GPC) and solid phase extraction (SPE) cartridges. The residues were simultaneously identified and quantified by GC-ECD equipped with dual tower, dual column and two micro-ECD detectors. The analytical performance was demonstrated by the analysis of 3 TCMs samples' extracts, spiked at three concentration levels for each pesticide. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) better than 15%, were obtained. The limit of detection (LOD) for most of the targeted pesticides tested was below 0.01 mg kg(-1). The method had good extraction efficiency, purification effect and good reproducibility, which could be applied to the determination of organochlorine and pyrethroid pesticide residues in the routine analysis of TCMs.