用残气谱研究HT—7超导托卡马克第一壁硼碳膜的吸氧性

硼碳膜吸氧将导致真空室残气中水分压的降低，所以可以通过分析各种情况下真空室残气谱水分压的变化，来研究托卡马克等一壁硼碳膜的吸氧过程，残气谱分析表明硼化过程中，硼碳膜吸氧；各种等离子体轰击过程中硼碳膜吸氧；而没有等离子体轰击时如抽本底真空过程中，硼碳膜不吸氧。了解这些过程对合理使用膜有重要意义。

上海光源溅射离子泵性能测试

本文详细介绍了上海光源常用溅射离子泵性能测试的方法和原理,并对极限真空度,有效抽速,洁净度进行了测试。结果表明,溅射离子泵的极限真空度测量值都满足≤5.0×10^(-8)Pa的指标要求。SIP200和SIP400的氮气再生抽速最大值均超过了各自的名义抽速,对惰性气体(氩气)的饱和抽速最大值也超过了名义抽速的60%。通过四极质谱计测得的残气谱图得出溅射离子泵的洁净度达到了上海光源光束线的洁净要求。经过测试的溅射离子泵安装到光束线上均能正常工作,动态真空满足设计指标。

Study on Analytical Method of Endosulfan Residue in Apple

This study was conducted to establish an analytical method for endosulfan residue in apple. Samples were extracted with 30 ml of acetone ： ethyl acetate （9：1）, purified with FlorisiL （containing activated carbon）, and detected by GC. Under those detection conditions, the detection limits of α-endosulfan, 15-endosulfan and endosulfate were 10^-11, 10^-11, and 2.5×10^-11 g, respectively. The recoveries of α-en- dosulfan were in the range of 89.49%-95.34%, with CVs in the range of 1.45%- 2.69%; the recoveries of β-endosulfan were in the range of 99.35%-100.63%, with CVs in the range of 1.39%-4.72%; and the recoveries of endosulfan suffate were in the range of 95.32%-101.15%, with CVs in the range of 1.19%-3.21%. The accu- racy, precision and sensitivity of the method all satisfy the requirements of pesticide residue analysis.

Simultaneous Determination of 8 Pesticide Residues in Green Tea Based on Gas Chromatography-mass Spectrometry

To improve pesticide residues detection efficiency in tea, simultaneous de- termination of eight pesticide residues in green tea was developed based on gas chromatography-mass spectrometry （GC-MS）. The results showed that, - detected by the GC-MS under following conditions： acetonitrile as extraction and elution solvent, activated carbon and PSA tandem column as the stationary phase, elution volume of 12 ml the relationship between peak area and concentration of each residue （ametryn in the range of 0-100 pg/L, napropamide in the range of 0-10 000 gg/L, other pesticides in the range of 0-1 000 tJg/L） were linearly related, and their corre- lation coefficients were all greater than 0.999. The recovery rate the pesticides added to tea sample at legal concentration limits ranged from 73.6% to 116.8%, and the relative standard deviation from 1.47% to 15.58%. The new method we de- veloped is sensitive, specific and anti-interference, and thus provides test basis for the development of pesticide matrix reference materials in tea.

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.

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.

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.

Analysis Method for Pesticide Residues in Biological Matrices： Gas Chromatography-mass Spectrometry

Pesticides have done a great service to human, but their use is not safe for public health. Apart from pesticides acute toxicity, their chronic toxicity can cause various problems for human health. The objective of this work was to validate a liquid-liquid extraction method, which allows a fairly reliable analysis of pesticides using gas chromatography-spectrometry mass （GC/MS） in toxicology laboratory at National Institute of hygiene, Rabat Morocco. The equipment required to perform these analyzes are the biological matrices （blood, gastric fluid）, in which the authors have doped the Organophosphorus pesticides such as Chlorpyrifos, Dichlorvos and Organochlorine pesticide： dichlorodiphenyltrichloroethane （DDT） and Heptachlor. After extracting the mixture with toluene, the supernatant was collected after centrifugation and concentrated in a small volume of 1.5 mL and then analyzed in GC/MS. After analyzing, the authors found that the yields of each pesticide in samples are significant; respectively they represented 73.4% of Chlorpyrifos, 70.8% of Dichlorvos, 47.8% of DDT and 71.6% of Heptachlor. The blood has a strong link with the most pesticides, where it＇s important to use the GC/MS to identify these products. The extraction with toluene was effective, especially to OP, but it＇s also sensitive to OC.

Translocation of Pesticide Residues in Tomato, Mango and Pineapple Fruits

Pesticide residues in fruit and vegetables have become a major concern associated with chemical food safety issues. Translocation of pesticides in tomato, mango and pineapple fruits in locally produced samples was investigated using gas chromatography/mass spectrophotometer （GC/MS） procedures. Samples were fractionated with respect to distance from the skin to the core and prepared for analysis. Results showed that organochlorine, organophosphate and synthetic pyrethroid residues were translocated in all fruit samples analyzed. With respect to tomato fractions, the peels retained more residues compared to the pulp and the central core. In the chemical species, organochlorines were retained more in the peels of tomato than the other fractions of the fruit. More organophosphate and organochlorine residues were detected in pineapple peels compared to the pulp. Synthetic pyrethroid residues were evenly distributed in the pineapple fruit. In mangoes, the pulp retained more chemical residues than other fractions of the fruit. More organochlorine residues were retained in the pulp of mango than in the other fractions of the fruit. Synthetic pyrethroid residues were evenly distributed throughout the mango fruit. All the chemical species identified were translocatable across the fractional parts of all the fruits. There were significant differences in translocation and residue accumulation of pesticides among the fractional parts of all samples.

Oxidation of Lingwu Coal Extraction Residue in Aqueous Sodium Hypochlorite under Mild Conditions

To investigate the structural features and provide an alternative method for high value-added utilization of coal, Lingwu coal was first extracted with organic solvent at room temperature. Then its extraction residue was oxidized in aqueous sodium hypochlorite(ASHC) under mild conditions. The effects of oxidation conditions, such as temperature, reaction time, the ratio of Lingwu coal extraction residue(LCER, g) to ASHC(m L) and p H value, on the product distributions and compositions were investigated. The results of gas chromatography/mass spectrometry(GC/MS) suggested that 53 kinds of methyl esterified products were detected in total, and benzene carboxylic acids were the main oxidation products, while chloro-substituted benzene carboxylic acids were the main by-products. Higher yield and fewer kinds of organic acids could be obtained at lower p H value, especially for the main objective product, benzene carboxylic acids.

Reliable screening of pesticide residues in maternal and umbilical cord sera by gas chromatography-quadrupole time of flight mass spectrometry

The widespread use of pesticides induces heavy adverse effects on human health,especially for the pregnant women and the newborns.In this study,a screening method has been developed for the determination of multi-pesticides in maternal and umbilical cord sera.All pesticides in sera were collected using solid phase extraction(SPE),and analyzed by gas chromatography-quadrupole time of flight mass spectrometry(GC-QTOF MS).To set up the quality criteria,a database of 50 pesticides was created and the accurate masses of 3 up to 5 representative ions with their intensity ratios were included for each pesticide.In addition,a novel"identification points"(IPs)system relying on the accurate MS1 and MS2 spectra was used to interpret the data for each suspected pesticide.The methodology was then applied to a pair of maternal and umbilical cord sera.A total of six pesticide residues were screened out successfully.In conclusion,GC-QTOF MS combined with an accurate mass database seemed to be one of the most efficient tools for systematic pesticide analysis.