Determination of 14 Organophosphorus Pesticide Residues in Mutton by Gel Permeation Chromatography-Gas Chromatography-Mass Spectrometry(GPC-GC-MS)

[Objectives]This study was conducted to purify mutton samples by gel permeation chromatography(GPC).[Methods]Fourteen organophosphorus pesticide residues in samples were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry(GC-MS)in selective ion scanning mode(SIM).[Results]The organophosphorus pesticide standard solutions showed good linearity in the mass concentration range of 0.1-10.0μg/ml with correlation coefficients(r)not lower than 0.999,and the detection limits(S=3 N)ranged from 0.01 to 0.05 mg/kg.The average recovery values were in the range of 80.2%-99.7%,with relative standard deviations(RSDs,n=3)in the range of 1.8%-6.3%,at the addition levels of 0.5,1.0 and 2.0 mg/kg.[Conclusions]The method is simple,sensitive and accurate,and can be used for the determination of organophosphorus pesticide residues in mutton.

Gel Permeation Chromatography Purification and Gas Chromatography-Mass Spectrometry Detection of Multi-Pesticide Residues in Traditional Chinese Medicine

The measurement of 23 organochlorine, organophosphorus, and pyrethroid pesticides in typical traditional Chinese medicine (TCM), flos lonicerae, was made using gel permeation chromatography (GPC) purification and gas chroma- tography-mass spectrometry (GC-MS) detection. The pesticides were extracted with ultrasonic device and 5.0 mL mixture of ethyl acetate and cyclohexane (1:1, v/v). Coextractants from sample matrices which may have interfere to the qualitative and quantitative analysis, such as pigments, were removed using GPC purification. Simultaneous full scan and selective ion monitor (scan/SIM) mode for GC-MS was used for qualitative and quantitative analysis, which pro- vided retention time and characteristic fragments ratio for each pesticide so as to positively identify each analyte. Rela- tive standard deviations (RSDs) were within 7.7% (5.0 - 22.5 μg/kg, n = 3). The recoveries of pesticide standards at the spiked concentration of 5.0 - 22.5 μg/kg were between 87.1% and 110.9%. Limits of detection (LODs) for the analytes were 0.16 - 3.2 μg/kg, which could meet the demand of routine analysis and TCM quality control.

Determination of Eight Organophosphorus Pesticide Residues in Pepper by QuEChERS-Gas Chromatography

[ Objectives] This study was conducted to establish a QuEChERS-gas chromatography method for determination of eight kinds of organophosphorus pesticide residues in pepper. [Methods] The samples were extracted by acetonitrile, and anhydrous magnesium sulfate was used for salting out. The extracts were then purified by dispersive solid phase extraction combining with GCB, C18 and PSA. Samples were analyzed by FPD detector. External standard was used as quantitive method. [ Results] The detection limits were in the range of 0. 001 -0. 008 mg/kg, the average recoveries ranged from 83.5% to 101.2% , and the relative standard deviation （RSD） of the eight organophosphorus pesticide residues were below 5%. [ Conclusions] The method is simple, quick, easy and effective for the determination of pepper.

Capillary gas chromatographic determination of dimethachlon residues in fresh tobacco leaves and cut-tobacco

Simple procedures for extraction and chromatographic determination of dimethachlon residues in fresh tobacco leaves and cut-tobacco are described.The determination was carried out by capillary gas chromatography(GC) with electron capture detection(ECD) and confirmed by GC-MS.The mean recoveries and relative standard deviation(RSD) were 93.2%～112.9% and 3.5%～6.7%,respectively at levels ranging from 0.01 to 0.1 mg/kg.The limit of determination was 0.001 mg/kg.Tobacco samples in routine check were successfully analyzed using the proposed method.

Chromatoprobe as a sample-sparing technique for residual solvent analysis of drug discovery candidates by gas chromatography

In drug discovery research, residual solvent measurement is an integral part of purity analysis for synthesis of a drug candidate before it is used for toxicity testing. This is usually carried out using gas chromatography(GC)with direct injection sample introduction. This method requires testing compounds to be soluble at high concentrations( > 50 mg/mL, usually in DMSO) to achieve acceptable sensitivity, a hurdle which is not always achievable for some samples such as cyclic peptides and oligonucleotides. To overcome the limitation associated with the direct injection approach, a new method using the Chromatoprobe thermal extraction device was developed for quantifying residual solvents of drug discovery compounds. This method not only consumes significantly less material(less than 1 mg), but also shows higher sensitivity than the direct injection approach.In addition, because no diluent is required with the Chromatoprobe thermal extraction, all residual solvents can be detected and measured without further method optimization. In our study, we compared data from GC residual solvent analysis using the Chromatoprobe solid sample introduction to those of the direct injection method for seven in-house samples. Our results showed a good agreement between the data from these two sample introduction methods. Thus, the Chromatoprobe sample introduction method provided a samplesparing alternative to the direct injection method for the measurement of residual solvents in drug discovery.This method can be particularly useful for residual solvent analysis in samples that are available only in limited amounts, poorly soluble, and/or unstable in the diluents used for the direct injection method.

Analysis of Residual Solvents in Annatto Extracts Using a Static Headspace Gas Chromatography Method

An analytical method for the quantification of residual solvents in annatto extracts, natural food colorants, was established using a static headspace gas chromatography (HSGC) coupled with a flame ionization detector (FID). As a sample diluent in a headspace sampling, dimethylformamide (DMF) was selected owing to its high capacity for dissolving both bixin-based and norbixin-based annatto extracts. The quantification of residual solvents was performed using the external standard method. The linearity of the calibration curves was assured with relative coefficients (R2) that were greater than 0.999. The recoveries of all standard solvents spiked in the annatto extracts were in the range from 95.1% to 107.1% to verify the accuracy and the relative standard deviation (RSD%) values (n = 3) were in the range from 0.57% to 3.31%. The quantification limits (QL) were sufficiently lower than the limits specified by Joint FAO/WHO Expert Committee on Food Additives (JECFA). With the established HSGC method, six residual solvents (methanol, ethanol, 2-propanol, acetone, ethyl acetate, and hexane) in 23 commercial annatto-extract products that consist of seven bixin-based and 16 norbixin-based products were quantified. The levels of residual ethyl acetate and hexane in all products were lower than the specified limits of JECFA. However, three samples of bixin-based products showed higher levels of residual 2-propanol (approximately 313.9 - 427.7 ppm) than the specified limit. Other bixin products also showed higher concentrations of residual methanol (approximately 166.6 - 394.7 ppm) and residual acetone (approximately 75.2 - 179.8 ppm) than the limits of JECFA. In the case of norbixin-based products, nine samples showed higher levels of residual acetone (approximately 42.6 - 139.5 ppm) than the limits of JECFA. This is the first survey of residual solvents in annatto extracts using the validated HSGC method.

Analysis of residual crosslinking agent content in UV cross-linked poly(ethylene oxide) hydrogels for dermatological application by gas chromatography

Acrylates have been widely used in the synthesis of pharmaceutical polymers. The quantitation of residual acrylate monomers is vital as they are strong irritants and allergens, but after polymerization, are relatively inert, causing no irritation and allergies. Poly(ethylene oxide)(PEO) hydrogels were prepared using pentaerythritol tetra-acrylate(PETRA) as UV crosslinking agent. A simple, accurate, and robust quantitation method was developed based on gas chromatographic techniques(GC), which is suitable for routine analysis of residual PETRA monomers in these hydrogels. Unreacted PETRA was initially identified using gas chromatography–mass spectrometry(GC–MS). The quantitation of analyte was performed and validated using gas chromatography equipped with a flame ionization detector(GC–FID). A linear relationship was obtained over the range of 0.0002%–0.0450%(m/m) with a correlation coefficient(r2)greater than 0.99. The recovery( 4 90%), intra-day precision(%RSD o 0.67), inter-day precision(%RSD o2.5%), and robustness(%RSD o1.62%) of the method were within the acceptable values. The limit of detection(LOD) and limit of quantitation(LOQ) were 0.0001%(m/m) and 0.0002%(m/m), respectively.This assay provides a simple and quick way of screening for residual acrylate monomer in hydrogels.

Determination of Fosthiazate Residue in Ginger by Gas Chromatography

[Objectives] An analytical method was established for determining fosthiazate residue in ginger by gas chromatography with flame photometric detector(GC-NPD) to evaluate the safety of fosthiazate in ginger. [Methods] The fosthiazate residue in ginger was extracted with dichloromethane, and subjected to sodium chloride salt-out and liquid-liquid extraction with hexane and dichloromethane(the plant and soil samples had no need for the later two steps). The analysis was performed on gas chromatograph equipped with a flame photometric detector(GC-FPD), and the fosthiazate residue was quantitatively determined by calculating the peak area. [Results] The results of degradation dynamics showed that the half-life of fosthiazate was 7.2-8.7 d in ginger plants, and was 9.9-19.8 d in the soil. The results of the final residue test showed that after applying the fosthiazate granules according to the recommended high dose(active component 58.2 g a.i/m^2,WK) and low dose(38.8 g a.i/m^2,WK) once, the final residual amounts of fosthiazate in the ginger and soil were estimated to be <0.02 mg/kg and <0.02-0.103 mg/kg, respectively, while no fosthiazate residue was detected in all control samples(<0.02 mg/kg). The maximum residue limit(MRL) of fosthiazate in ginger was not established in China, and was 0.2 mg/kg in Japan. [Conclusions] The method was proved to meet the basic requirements of pesticide residue analysis on sensitivity, accuracy and precision and have good linearity. It is recommended that when using fosthiazate granules to control root-knot nematode and root rot in ginger, it is applied at the highest dose of 38.8 g ai/m^2,WK once 30 d before ginger cultivation to treat the soil, and ginger is harvested in the ginger harvest period.

Research on Comparison of Gas Chromatography and Liquid Chromatogram Detecting Pesticide Residue

The existing methods of detecting pesticide residue include gas chromatography, high performance liquid chromatography, gas chromatograph-mass, liquid chromatograph-mass, capillary electrophoresis, radioimmunoassay, biosensor and rapid detection on the spot. The paper analyzes the comparison of gas chromatography and liquid chromatogram detecting pesticide residue, for achieving the development tendency and the future goal of analyzing pesticide residue.

Trace Residue Analysis of the Herbicide Imazethapyr in Soil by Gas Chromatography-Nitrogen/Phosphorous Detector

A gas chromatographic method for determining the trace residue of imazethapyr {(±)-2-[4,5-dihydro-4-methtyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-ehtyl-3-pyridinecarboxylic acid} in soil was described in this paper. The soil samples were extracted by shaking with 0.5 mol·L -1 sodium hydroxide solution. The aqueous extract was acidified with hydrocholric acid to adjust the pH to 2.0 to precipitate humic acids, then was extracted with dichloromethane. The organic extract was dried with anhydrous sodium sulfate and was concentrated. After florisil cleanup, and imazethapyr is derivatized with trimethylanilinium hydroxide (TMAH). Methylated imazethapyr was analyzed by gas chromatography with a nitrogen-phosphorous dtector. The recovery of imazethapyr from soil samples are over 80%, the experimental detection limit of the method is 5ng·g -1 .

Matrix Effects of Fourteen Organophosphorus Pesticides Residues in Nine Kinds of Vegetable Matrices

The matrix effects of 14 organophosphorus pesticides in 9 kinds of vegetables matrices were preliminarily studied by gas chromatography/flame photomet- ric detection（FPD） in the paper. The matrix effects of 14 organophosphoms pesticides in 9 kinds of vegetable matrices at 0.05, 0.1 and 0.2 mg/L were compared, respectively. The results showed that matrix enhancement effect and matrix attenuation effect existed in all cases, while matrix effects did not have strong correlation with concentrations of pesticides, but were related to species of vegetables and structure and polarity of pesticides.

Rapid Determination of Pesticide Residues in Fresh Sweet Corn

Objective] This study aimed to detect al organophosphate, organochlorine and pyrethroid pesticide residues in fresh sweet corn in one determination using a gas chromatograph. [Method] The pesticide residues in fresh sweet corn were ex-tracted and loaded to simultaneously the gas chromatograph Agilent 6890N which was equipped with two autosamplers, two columns and two detectors. [Result] Al the 26 pesticides were completely separated and eluted out within 25 min. The re-coveries of standard addition of the 26 pesticides ranged from 76% to 106%, with relative standard deviations （RSD） ranging from 0.5% to 8.9%. The linear regression equation fit wel from 0.050 to 1.500 mg/L corn extract （r2＆gt;0.996）. [Conclusion] The method is accuracy, which meets the requirements of pesticide residue analysis and can be used for the rapid detection, qualitative and quantitative analysis of pesticide residues in fresh sweet corn.

Determination of Organochlorine and Synthetic Pyrethroid Pesticide Residues in Water Samples Collected from Different Locations of Bangladesh

The present study was aimed to validate an analytical method for the quantification of 19 organochlorine and 2 synthetic pyrethroid pesticide residues in water samples using modified quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and Gas Chromatography coupled with Electron Capture Detector (ECD). The selected pesticide residues were determined by in-house validated method. The analytical method was validated by evaluating the accuracy, precision, linearity, limit of detection (LOD) and limit of quantification (LOQ). The average recoveries of the selected pesticides ranged from 78% to 117% with RSDr ≤ 12% in two fortification levels of 0.02 and 0.1 mg/L. The linearity was ≥0.995 for all of the selected pesticides. The LOD ranged from 0.003 to 0.006 mg/L and the LOQ was 0.02 mg/L for all the selected analytes. This method was applied satisfactorily for the residue analysis of 108 water samples collected from nine districts of Bangladesh. Among the analyzed samples, only 4 had cypermethrin residues (0.026 mg/L, 0.034 mg/L, 0.045 mg/L and 0.05 mg/L). The level of detected cypermethrin residues were above the WHO recommended guide line values of water quality.

应用GC-MS/MS技术检测水果蔬菜中22种残留农药

To establish a new GC-MS/MS method for quantitative detection of 22 kinds of pesticide in fruit and vegetable including organic phosphorus,carbamate & pyrethrin etc.Working was performed by Xcalibur software with multitask mode.We Carried on qualitative and quantitative analysis to mass spectrum of MS/MS in order to obtained a credible experiment result.This method is sensitive and accurate,it is suitable for determination of multifarious pesticide residues.

衍生固相萃取GC-MS检测牛可食组织中克伦特罗的残留量

盐酸克伦特罗(clenbuterol,CLB),俗名"瘦肉精",化学名为"2-[(叔丁氨基)甲基]-4-氨基-3,5-二氯苯甲醇盐酸盐"(相对分子质量313.5),是一种β-兴奋剂[1].近年来动物性产品中CLB残留对人类健康造成的危害和对生态食物链所造成的破坏已经引起高度重视.……

Study on Detection of Organochlorine Pesticide Residue in Ginseng

To investigate the residue situation of pesticides in ginseng, total 17 samples of ginseng-growing soil, ginseng roots and ginseng seeds were collected from 5 regions of Fusong County, and the contents of organochlorine pesticide residues in the samples were detected by using ultrasonic-assisted extraction and gas chromatography with acetone-ligroin as the solvent, thereby providing suitable recommendations and scientific basis for the selection of ginseng-growing soil.

大豆植株和土壤中异丙草胺残留分析

建立了除草剂异丙草胺在大豆和土壤中的残留分析方法。样品用甲醇与水的混合液提取,石油醚萃取,柱层析净化,GC-μECD检测,方法最小检出量为7.4×10-12g。土壤、大豆植株和籽粒中最小检测质量分数均为0.0018mg/kg,在添加水平分别为0.01、0.1、1.0mg/kg时,样品中的异丙草胺在土壤、大豆植株和籽粒中的添加回收率为分别为81.3%～96.7%、81.2%～92.5%、82.2%～92.1%,变异系数为1.60%～3.07%。

环境中异丙草胺农药残留分析方法

建立了新型除草剂异丙草胺在环境水及土壤中的残留分析方法.水样用二氯甲烷提取后即可进样测定;土样用石油醚:丙酮=1:1(v/v)的混合液提取,石油醚液液分配,氟罗里硅土层析柱净化,然后GC-ECD进行检测.水及土壤中异丙草胺残留方法的最小检测浓度分别为0.2μg/L和1.8μg/kg,回收率在85.7%～102.6%之间,变异系数为1.3%～6.6%.

Investigation of the False Positive Results of Dithiocarbamate Pesticides due to Endogenous Nonpathogenic Carbon Disulfide in Organically Grown Plants (Moringa oleifera)

Moringa plant belongs to the family Moringaceae within the order Brassicales. It is a magical plant which contains 7 timesthe vitamin C content of oranges,4 times the vitamin A content of carrots, 4 times the calcium content of milk ,3 times the potassiumcontent of bananas and 2 times the protein content of yogurt (gram to gram) . The most widely distributed species is Moringa oleiferaLam., referred as drumstick tree for the shape of its seed pods. Leaves of M. oleifera are rich in a unique glucosinolate namedglucomoringin. Moringa were found to release CS2 when submitted to experimental conditions of dithiocarbamate residue analysis.Gas chromatography was used to quantitate CS2 and control samples were obtained from Moringa plantations cultivated inexperimental areas, in which no treatment with fungicides of the dithiocarbamate group was applied. Endogenous CS2 levels werecompared with dithiocarbamate residues measured in Moringa samples from the field trials following applications of the macozeebfungicide. Use small leaves resulted in an observed decrease in CS2 concentration comparable to the large leaves. Temperature levelused has an effect on the concentration of CS2 measured as an indicator for dithiocarbamate pesticide residue. And use of hightemperature (100 °C) in drying of Moringa leaves after harvesting may lead to some biochemical changes that caused an observedincrease in CS2 concentration comparable to drying at (50 °C). Evidence for formation of dithiocarbamate compound from moringinin moringa leaves are metabolized/detoxified principally by the mercapturic acid pathway. Conjugation with glutathione (GSH)promoted by glutathione transferases gives rise to the corresponding Glucosinolate -. Isothiocyanate conjugates. These undergofurther enzymatic modifications to give rise sequentially to the cysteinylglycine cysteine - Isothiocyanate andN-acetylcysteine-Isothiocyanate conjugates, all of which are dithiocarbamates. The detection of an ion with a m/z value 430.40, withthe following fragments m/z 165.10 and m/z 121.05 respectively, among the ions analyzed by GC-MS gives a clear evidence forformation of dithiocarbamate by addition of glutathione to the isothiocyanate formed from glucosinolate in moringa plant.

Study on Relationship Between Cucumber Germplasm and Propamocarb Residue Using Subjective Rating Technique

Propamocarb （PM） residue in cucumber （Cucumis sativus L.） receives little attention. As is well known to all, high PM residue of cucumber could lead to increase in the violation rates of maximum residue limits and ultimately cause harm to human health. Knowledge of PM residue could help cucumber breeders in developing cultivars with low PM residue and improving cucumber quality. In this study, 32 representative cucumber accessions （26 breeding lines and six cultivars） from different regions of China were evaluated for their PM residue in fruit and leaf to provide meaning to the subjective rating, which was highly correlated with PM residual content of fruit （r=0.97） and leaf （r=0.94）. In addition, PM residual content of North China ecotype was the highest and Pickling ecotype was the lowest in fruit and leaf of cucumber. The leaf had significantly higher （P〈0.01） PM residual content than the fruit, and poor correlation between leaf and fruit was represented. This study verified PM residual relationship between fruit and leaf, and laid the foundation for further identification of germplasm resources and breeding of new varieties for low PM residue of cucumber.