Residue analysis and dissipation of monosulfuron in soil and wheat

HPLC-UV residue analytical method for monosulfuron [N-[( 4' -methyl) pyrimidin- 2' -yl]-2-nitrophenylsulfonyl urea] in soil and wheat was developed. Monosulfuron residues were recovered by solvent extraction, followed by liquid-liquid partition, and C 18 cartrige clean-up. Excellent method recoveries ranging from 95%—104% for both fortified soil and wheat grain were obtained with coefficients of variation 1.5%—11.8%. The minimum detectable quantities in soil and wheat were both 4 ng, the limit of detection was 0.02 mg/kg. When monosulfuron was applied according to double dosage of maximum recommended use direction(120 g ai/hm 2 of 10% monosulfuron wettable powder sprayed for once during development of wheat) in field studies conducted in Shandong Province and near Beijing, monosulfuron residues was not detected in soil and wheat samples collected 75 d after application. Laboratory soil degradation studies showed that monosulfuron degraded faster in acidic soil and strong alkaline soil than in neutral or weak alkaline soil. Half lives in Jiangxi soil, Shijiazhuang soil, Jiangsu soil and Heilongjiang soil were 41, 48, 87 and 84 d respectively. Monosulfuron residues dissipated rapidly in Shandong and Beijing field test sites with half-lives of less than 14 d.

Residue analysis and dissipation of a new fungicide 2-allylphenol in tomato

The method of residue analysis of a new synthesized fungicide 2-allylphenol was studied by simulating the active compound structure in Gingko tree(Gingko biloba L.) and its dissipation rate and terminal residue levels in tomato under field condition. Residues of 2-allylphenol were extracted from tomato matrix with acetone, purified by liquid-liquid extraction and Florisil cartrieges, and then determined by HPLC with UV-detector. The minimum detectable amount of 2-allylphenol was 3×10 -9 g, the minimum detectable concentration of 2-allylphenol in the samples of tomato were 0.01 mg/kg. The ranges of average recoveries and coefficient variation of the method were 87.7%—90.2% and 1.25%—2.06%, respectively. The dissipation rate and terminal residue levels in tomato were determined with the method described above. The results showed that the half-life of 2-allylphenol in tomato was 6.37 d, and 2-allylphenol declined with 82.6% of the initial deposit remaining in tomato at harvest. The terminal residue levels in tomato were 0.15 mg/kg and 0.20 mg/kg following the recommended doses and time intervals.

Residue Analysis of 55% MCPA·ametryn·diuron WP

The digestion regularity of MCPA, ametryn and dim＇on which were the active ingredients of 55% MCPA · ametryn · diuron WP in sugarcane leaves and soil of sugarcane plantation collected from Changsha of Hunan Province and Haikou of Hainan Province in 2009 and 2010were studied in the paper, and the results showed that these three agents had rapid digestion. The final residue test showed that beth MCPA and ametryn had not been detected in the study; the average resi- dues of diuron in the soil collected from Hunan Province in 2009 and 2010 were 0.018 and 0.015 mg/kg, respectively which were slightly larger than the critical value of 0. 013mg,/kg; diuron had no been detected in other treatments.

Published the papers of GC-MS analysis—Chemical drug

Song Qi, Liu Hu; Gao Shu. Screening and quantitative analysis of volatile markers in the breath of patients with breast cancer Acta Universitatis Medicinalis Anhui, 2010, 45（01） ：76-79.

LOCATION OF DOUBLE BOND POSITION OF INSECT SEX PHEROMONE BY GC/MS ANALYSIS WITH CHEMICAL IONIZATION

Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the characteristic fragment ions were high in m/z,thereby the interpretation was facilitated.

Determination of Indoxacarb Residue in Foodstuffs of Plant and Animal Origin by GC-ECD and LC-MS/MS

An effective method for the trace analysis of indoxacarb residue in foodstuffs of plant and animal origin [grapefruit, ginger, fresh soybean, bamboo shoot, qing-gen-cai （cruciferous vegetable）, chicken, fish, and pork] was developed using gas chromatography （GC-ECD） and liquid chromatography tandem mass spectrometry （LC-MS/MS）. Samples were extracted using acetone and n-hexane mixed solvent （1：2, v/v） and then purified using solid-phase extraction （SPE） columns. The extracts were analyzed using GC-ECD and LC-MS/MS. The multiple reaction monitoring （MRM） scheme used involved transitions of the precursor ions to selected two product ions in which one pair for identification was m/z 529 → 293 and another pair for quantification was m/z 529 → 249. The detection limits （LODs） of the method were 0.0015 and 0.0006 mg kg^-1, and the quantification limits （LOQs） were 0.005 and 0.002 mg kg^-1 for GC-ECD and LC-MS/MS, respectively. The relative standard deviations （RSDs） of recovery for indoxacarb were lower than 15% in 10 types of agro-products. Ten repetitive determinations of recovery achieved good reproducibility for indoxacarb and the recovery ranged from 72.08 to 113.74%. The proposed procedure was applied to the analysis of several real samples of different origin from Fujian Province, China, and 299 samples were screened for indoxacarb residue, of which 5 positive samples were found.

Molecular Characterization of Hydrotreated Atmospheric Residue Derived from Arabian Heavy Crude by GC FI/FD TOF MS and APPI FT-ICR MS

High resolution mass spectrometry in combination with distillation and SARA fractionation provides us an opportunity for in-depth understanding about the hydrotreating process at the molecular level. In this study, the atmospheric residue derived from Arabian heavy crude and its hydrotreated products were initially subjected to distillation and SARA fractionation. The saturates were characterized by GC FI/FD TOF MS. The aromatics and resins were characterized by APPI FT-ICR MS. Compositional changes of different compounds (paraffins, naphthenes, aromatic hydrocarbons, and heteroatomic compounds) contained in different distillates (vacuum gas oil, vacuum residue) were obtained. More detailed knowledge about the hydrotreating process was achieved.

Multi-Residue Determination of Eight Anabolic Steroids by GC-MS in Muscle Tissues from Pigs

A gas chromatography-mass spectrometry （GC-MS） method to determine eight anabolic steroids （diethylstilbestrol, methyltestosterone, norethindrone, 17α-ethynylestradiol, estradiol, 6α-methyl-17α-hydroxy-progesterone, estradiol benzoate, and chlormadinone acetate） was developed. Muscle samples were extracted with liquid-liquid extraction and clean-up was performed in two steps, the extracts obtained were derivatized with heptafluorbutyric （HBF） anhydride and analyzed by GC-MS. In the above method, the linear scope was 2.5-50 μg kg^-1. The range of the recoveries was 78.5-148% for diethylstilbestrol, 70.8-109% for methyltestosterone, 69.8-87.2% for norethindrone, 67.7-120% for 17α-ethynylestradiol, 82.8-103% for estradiol, 70.3-99.2% for 6α-methyl-17α-hydroxy-progesterone, 73.0-104% for estradiol benzoate, and 72.9- 91.8% for chlormadinone acetate. The range of the coefficients of variation within batches was 0.4-12%; the range of the coefficients of variation between batches was 6.4-11%. The limit of detections and the detection capability were 0.99 and 3.30 μg kg^-1 for diethylstilbestrol, 1.05 and 3.50 μg kg^-1 for methyltestosterone, 1.19 and 3.97 μg kg^-1 for norethindrone, 0.94 and 3.13 μg kg^-1 for 17α-ethynylestradiol, 1.45 and 4.83 μg kg^-1 for estradiol, 1.56 and 5.20 μg kg^-1 for 6α-methyl-17α- hydroxy-progesterone, 1.92 and 6.40 μg kg^-1 for estradiol benzoate, and 2.41 and 8.03 μg kg^-1 for chlormadinone acetate, respectively. These results showed that the method was widely available, accurate, and sensitive.

Chemical composition, antioxidant activity and GC-MS analysis of juice and peel oil of grapefruit varieties cultivated in India

Citrus family especially Grapefruit,has attained considerable attention due to the presence of a number of essential components that have cardiovascular and anti-hypertensive properties.The juice and essential oil extracted from eight recently released grapefruit cultivars were used to study physicochemical and antioxidant properties.The total soluble solids(TSS),titratable acidity(TA) and pH of juice samples extracted from various grapefruit varieties differed significantly.The refractive index,specific gravity and optical rotation values for the oil varied from 1.473 to 1.396,0.863 to 0.847 and +93 to +86,respectively.The percent 2,2-diphenyl-1-picrylhydrazyl radical activity(% DPPH activity) and ferric reducing antioxidant power(FRAP) values for grapefruit juice and peel oil varied from 24.06 to 18.79,2.91 to 1.44 mmol g^–1 and 84.87 to 74.73,7.76 to 5.73 mmol g^-1,respectively.There were significant differences in physicochemical,antioxidant properties and volatile profiles of extracted juice and oil.The oil exhibited higher DPPH and FRAP values than the juice.Among different components identified which accounted for over 99% of the volatile fraction,limonene,myrcene,and benzopyran were major components in all oil samples.

Residue of Organphosphorus Pesticides in Chewing Cane Juices Detected by QuEChERS and GC-NPD Method

[ Objective] The paper was to establish a quick detection method for residue of organphosphoras pesticides in chewing cane juices and provide guarantee for edible safety of chewing juice. [ Method] By using QuEChERS and GC-NPD method, a rapid analysis method for residue of six kinds of organphosphorus pesti- cides （dichlorves, chlorpyrifos-methyl, malathion, fenthion, chlorpyrifos and triazophes） in sugarcane juices was established. [ Resdt] QuEChERS method was significantly superior to traditional extraction method and could extract six kinds of organphesphorus pesticides from chewing cane juices effectively, which gready saved organic reagent and time. Good linearity was found in different standard curves; when the concentration of pesticides was from 0. 020 toO. 100 rag/L, the re- covery rate was from 68.58% to 92.85%, and relative standard deviation （RSD） was ranged from 2.16% to 9.89%. [ Conclusion] The sensitivity, accuracy and precision of QuEChERS method were consistent with the technical requirements of pesticide residue determination. It not only could shorten sample processing cycle effectively, but also ensure that no impurity was in the sample peak and the recovery rate was also consistent with the requirements of residual analysis.

Analysis of vapor phase organics in air of Beijing, Langfang and Tianjin by capillary GC and GC/MS

The vapor phase organics (VPOs) in the air of Beijing, Langfang and Tianjin were detected by a capillary gas chromatography and GC/MS during the winter and the summer separately. The tentatively identified compounds include alkanes, cyclic hydrocarbons, alkenes, aromatics, acids, alcohols, aldehydes, ketones, esters, halocarbons and so on. The numbers of VPOs found are 118 in Beijing, 83 in Lang-fang and 65 in Tianjin in the winter, and 56, 39 and 72 in the summer respectively. Based on the data of some representative compounds determined quantitatively by GC and GC/MS, a profile of organic pollution in the air of the three cities is presented.

Antibacterial, Antioxidant Activities and GC-MS Analysis of Dichrostachys cinera (L.) Ethanolic Leaves Extract

Traditional medicinal plants are one of the potential sources of antimicrobial drugs and there is a great concern in the use and development of herbal medicine for the treatment of various infections. This study aimed to evaluate the antibacterial, and antioxidant activities of Dichrostachys cinera ethanolic leaves extract and to determine the components of the crude extract. D. cinera extract was evaluated against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853. The antibacterial, antioxidant activities and active constituents were determined using standard methods. Antibacterial activity of the crude extract findings showed that all bacterial candidates were susceptible where S. aureus represent MIC at 12.5 mg/ml and MBC at 25 mg/ml, E. coli and P. aeruginosa both showed MIC 25 mg/ml and MBC 50 mg/ml. In the free radical scavenging assay of the extract and the standard quercetin at concentrations of 250 μg/ml, 125 μg/ml, 50 μg/ml, 10 μg/ml, and 5 μg/ml. The radical scavenging activity for the extract was about 92%, 89.6%, 86.8%, 82.8% and 37.8% respectively, compared to quercetin which gave 89.7%, 85.8%, 62.1%, 55.5%, and 45% radical scavenging activity. The GC-Ms analysis of the total constituents demonstrated that 1,6-Anhydro-2,4-dideoxy-.beta.-D-ribo-hexo (21.26%) with different peaks, followed by Glycerin (11.56%), 1,2,3-Cyclopentanetriol (10.18%), 8,11,14-Eicosatrienoic acid, (Z,Z,Z)-(6.18%), 1H-Pyrrole, 1-methyl-(6.08%), Phytol (5.91%) and 7-Bromo-6-(2-diethylaminoethoxy)-2,3-dihyd (5.44%) as major components in the extract. Finally, this study provided useful information on the therapeutic potential of D. cinera as an antibacterial agent and recommended to be evaluated against a wide range of Bacterial and fungal strains using different solvents and different parts from the plant.

Evaluation of the Equality of Non-Polar Capillary Columns in GC/MS Analysis of Food Contact Plastics

Non-polar capillary columns for GC/MS are widely utilized in the analysis of additives for food contact materials. Though various kinds of non-polar capillary columns are commercially available, the equality of their performance has not been verified. Herein, ninety-six additives for food contact plastics were analyzed using fifteen kinds of columns, and the peak separation, retention times, and peak areas of each additive were compared. The additives, with various chemical properties, comprised forty four plasticizers, twenty lubricants, twenty antioxidants, nine ultraviolet absorbers, and three other compounds. 10 μg.mL-1 test solutions were prepared in acetone, and injected to the GC/MS. The fifteen columns were classified into five categories based on the chromatogram pattern and peak separation. To facilitate comparison of the retention time and detection sensitivity of the columns for the additives, the relative retention time (RRT) and relative peak area (RPA) were calculated by using dibutylphthalate or 4-tert-butylphenylsalicylate as an internal standard. The RRTs of the additives on each column were essentially similar. However, the RRT of the additives which were detected in the later stages differed slightly. Although the RPA of the plasticizers and lubricants were roughly similar, column-to-column differences were observed for certain additives, such as antioxidants and ultraviolet absorbers. Furthermore, certain fatty acids, antioxidants, two plasticizers, and two benzophenone type ultraviolet absorbers were not detected in the chromatograms of two columns.

Study on Fractional Separation and GC-MS Analysis of Flash Coal Tar Pyrolysed at Low Temperatures

The composition of low temperature pyrolysis coal tar has an effect on its further processing and reasomble utlization In this paper, the compeition or coal tars produced from both low temperature pyroysis in a fluidized bed aud flash pyrolysis with solid heat carrier have been investigated by the methch of fractional seperation and Gas Chromatography-Mass Spectrometry (GC-MS)- It is observed that the degree of coalification maceral and secondary reaction temperature (freeboard temperature in a fluidized bed) have some iufluence on the composition of coal tars- The main compoundes are phenol cresols,xylenols, naphthalene, alkylnaphthalenes, antbraceue, phenanthrene,acenaphthylene, fluoren, indene and so

山苍子油的有机溶剂浸提及其抗氧化活性与 GC-MS 分析

以不同有机溶剂作为提取介质,获得山苍子油,采用DPPH法比较不同提取介质(不同极性的有机溶剂)对山苍子油抗氧化活力的影响,并对抗氧化性差异较大两款山苍子油(甲醇、戊烷浸提)进行GC-MS组分分析,以1,4-二溴苯为对照品,运用气相色谱面积归一化法确定各组分的相对质量分数.在此基础上,探讨山苍子油有机组分与其抗氧化活性之间的关系.研究结果表明:以甲醇浸提获得的山苍子油具备最显著的抗氧化活性(IC50=3.72mg/mL),石油醚最弱(IC50=9.25mg/mL);GC-MS分析结果表明:以甲醇为提取介质得到的山苍子油,其脂肪酸和萜烯氧化物质量分数各占68.33%和6.80%,明显高于低极性的提取介质戊烷的45.57%和4.50%.

Study on the relationship between psoriasis vulgaris and GC gene in Hainan Han nationality based on target gene capture sequencing

Objective:To investigate the relationships between GC gene polymorphisms and psoriasis vulgaris.Methods:A total of 101 patients with psoriasis vulgaris and 79 healthy controls were enrolled into this study,and they were all of Han nationality from Hainan province.The target gene capture sequencing method was used to sequence the full length of the GC gene and its 2kb upstream and downstream regions.SNP-based association analysis was performed under four genetic modes in SNPs with minimum allele frequency greater than 1%and the P value of Hardy-Weinberg equilibrium test in the control group is greater than 0.05.Bioinformatics methods were used to predict the impact of risk SNP on gene function.Results:A total of 94 SNPs were detected,of which 93 met the inclusion criteria.SNP-based association analyses showed that 21 SNPs(16 in introns,2 in exons,and 3 in Untranslated Regions)were susceptible to psoriasis vulgaris in at least one genetic mode(OR=0.289‑2.295,95%CI=0.048‑12.670,P<0.05).Bioinformatic prediction indicates that rs4588,located in the exon 11,was a non-synonymous mutation and can convert threonine to lysine(SIFT Score=0.481,SIFT Score Pred=T).rs4752 A>G located in the exon 8 was a synonymous mutation and did not cause amino acid change.Conclusion:GC gene is associated with the susceptibility of psoriasis vulgaris in Hainan Han ethnic group.

基于安捷伦490 micro GC煤矿井下气体分析方法的研究

利用安捷伦490micro GC进行矿井气体分析,使用标准气体校准标准气体的方式,验证井下气体分析过程中不同方法产生的误差。主要针对甲烷气体浓度进行了分析,得出了低浓度标准气体测得高浓度标准气体结果偏高、高浓度标准气体测低浓度标准气体结果偏低的结论,提出了不同浓度标准气体测量气样的参考范围,达到了减小误差的目的,保证了气样分析的准确性。

Multiresidue pesticide analysis in tomato using GC-MS/MS using modified QuEChERS method with titanium-coated graphite with CNT-ABS nanocomposite as dispersive solid-phase extraction materials

The presence of pesticide residues in food and vegetables is a growing concern for consumers.To monitor these residues reliably,a selective and sensitive multiresidue system has been developed and validated in tomato by gas chromatography–tandem mass spectrometry(GC-MS/MS).Titanium-coated graphite with carbon nanotube(CNT)in acrylonitrile–butadiene–styrene(ABS)used as reversed-dispersive solid-phase extraction materials with modified QuEChERS(Quick,Easy,Cheap,Effective,Rugged,and Safe)method.Titanium-coated graphite with CNT-ABS is synthesized,characterized by X-ray diffraction and scanning electron microscopy.The clean-up performance of titanium-coated graphite with CNT-ABS was demonstrated to be better to primary secondary amine and graphitized carbon black cartridges.The processing of two multiple reaction monitoring transformations for each analyte is done using GC-MS/MS in electron impact mode.Satisfactory purification and recovery effects(74%–100%)of 35 pesticides were achieved in tomato matrices when using 5 mg of titanium-coated graphite ABS-CNT nanocomposite.It was observed that quinolphos and deltamethrin are present above the maximum residue limit.The technique proved to be reliable and sensitive in tomato samples for the routine testing of 35 pesticides.

Co-pyrolysis of Sewage Sludge with Distillation Residue: Kinetics Analysis via Iso-conversional Methods

This study explored the synergistic interaction of sewage sludge(SS)and distillation residue(DR)during co-pyrolysis for the optimized treatment of sewage sludge in cement kiln systems,utilizing thermogravimetric analysis(TGA)and thermogravimetric analysis with mass spectrometry(TGA-MS).The results reveal the coexisting synergistic and antagonistic effects in the co-pyrolysis of SS/DR.The synergistic effect arises from hydrogen free radicals in SS and catalytic components in ash fractions,while the antagonistic effect is mainly due to the melting of DR on the surface of SS particles during pyrolysis and the reaction of SS ash with alkali metals to form inert substances.SS/DR co-pyrolysis reduces the yielding of coke and gas while increasing tar production.This study will promote the reduction,recycling,and harmless treatment of hazardous solid waste.

基于GC-MS和快速气相电子鼻对我国东北地区代表性粳米香气组分分析

为探究我国东北地区4种代表性粳米(香米五优稻4号、绥粳18和非香米龙粳31、盐丰47)香气组分差异,通过顶空-固相微萃取-气相色谱-质谱联用(HS-SPME-GC-MS)和快速气相电子鼻(Flash GC e-nose)技术对粳米香气组分进行鉴定。研究采用正交偏最小二乘法-判别分析(OPLS-DA)和层次聚类分析(HCA)等方法对4种粳米香气组分进行分析,结果表明,4种粳米的主要香气组分构成类似,以己醛、壬醛等醛类为主;五优稻4号主要香气成分含量显著(P≤0.05)高于其他3个品种粳米,使得其香气更加浓郁;关于粳米香气组分鉴定技术,GC-MS技术的准确度和检测范围优于电子鼻技术,而检测效率低于电子鼻技术。