反气相色谱法研究煤直接液化残渣经分级提取前后的表面性质变化

采用反气相色谱法（IGC）分别对煤直接液化残渣（DCLR）脱灰处理后不溶物、正己烷不溶物、甲苯不溶物、四氢呋喃不溶物的表面性质进行表征。基于非极性探针净保留体积V_n分别采用Dorris-Gray方法和Schultz方法得到表面色散自由能,基于极性探针V_n得到吸附焓△H^sp,并通过△H^sp作图计算得到酸常数K_a和碱常数K_b。结果表明,经溶剂分级提取后表面色散自由能、K_a和K_b均发生明显变化。而DCLR呈现两性偏碱性这一特征并未随分级提取发生改变。IGC作为一种动力学吸附技术,可快速准确表征DCLR在经分级提取过程中表面性质的变化,相同温度下应用Dorris-Gray方法得到DCLR表面色散自由能略高于Schultz方法。     

Validation of a multiresidue method for the determination of pesticides in honeybees by gas chromatography

The validation of a multiresidue method for the determination of organochlorine, organophosphorus, pyrethroid and dicarboximide pesticides in honeybees is described. The method involves the extraction of 25 pesticides using acetonitrile, liquid partitioning with n-hexane and a clean-up performed on a silica gel cartridge (1 g, 12 mL). Capillary gas chromatography with electron-capture and nitrogen–phosphorus detectors was used for analytes determination. Limit of quantification (LOQ), recovery and relative standard deviation (RSD) for each analyte were determined. The recovery data were obtained by spiking honeybee samples free of pesticides at three levels (LOQ, 4LOQ and 8LOQ) with organochlorine, organophosphorus, pyrethroid and dicarboximide pesticides. The recoveries were in the range between 90.0% and 101.5% for LOQ, between 90.3% and 104.8% for 4LOQ and between 88.1% and 101.6% for 8LOQ with RSD less than 20% for the three levels tested. The lowest LOQ value was 1 ng bee^?1 (corresponding to 10 ng g^?1) and the highest LOQ value was 10 ng bee^?1 (corresponding to 100 ng g^?1). These LOQ values are lower than the lethal doses LD₅₀ (acute contact toxicity and acute oral toxicity) of each pesticide for bees.     

Analytical performance of the various acquisition modes in Orbitrap MS and MS/MS

Quadrupole Orbitrap instruments (Q Orbitrap) permit high‐resolution mass spectrometry‐based full scan acquisitions and have a number of acquisition modes where the quadrupole isolates a particular mass range prior to a possible fragmentation and high‐resolution mass spectrometry‐based acquisition. Selecting the proper acquisition mode(s) is essential if trace analytes are to be quantified in complex matrix extracts. Depending on the particular requirements, such as sensitivity, selectivity of detection, linear dynamic range, and speed of analysis, different acquisition modes may have to be chosen. This is particularly important in the field of multi‐residue analysis (eg, pesticides or veterinary drugs in food samples) where a large number of analytes within a complex matrix have to be detected and reliably quantified. Meeting the specific detection and quantification performance criteria for every targeted compound may be challenging. It is the aim of this paper to describe the strengths and the limitations of the currently available Q Orbitrap acquisition modes. In addition, the incorporation of targeted acquisitions between full scan experiments is discussed. This approach is intended to integrate compounds that require an additional degree of sensitivity or selectivity into multi‐residue methods.     

克伦特罗残留的GC-MS确证分析及应注意事项

克伦特罗(clenduterol,C12H18Cl2N2O)属β兴奋剂类,俗称为瘦肉精,畜牧业上可作为生长促进剂,其药物残留对人类健康有危害,我国农业部将其列为食品动物禁止使用的兽药。对于动物组织、尿中盐酸克伦特罗残留的测定,一般是先用酶联免疫检测法进行筛选,由于酶联法存在假阳性问题,对检测结果呈阳性的样品需再用气相色谱-质谱法进行确汪检测。本文建立并验证了与酶联免疫检测法相配套使用的猪尿和猪肝中克伦特罗残留的GC-MS确证方法,并对来自全国抽检的猪肝样和尿样中的酶联阳性样品进行了确证检测,结果报道如下。     

环境和生物样品中多来宝残留量的气相色谱分析方法研究

湿性样品中的多来宝残留物用丙酮（水样和干样用石油醚）提取，提取液经石油醚再萃取、浓缩后，用被石油醚饱和的乙腈分配，过硅胶氧化铝混合柱净化，室温下与（ＣＨ３）３ＳｉＩ衍生化反应，生成３－苯氧基苄基碘，用ＧＣ检测。当添加浓度为０．０５，０．１０，１．００μｇ／ｇ时，样品的平均回收率为８０．７％～１１０．０％，方法最小检出量为０．０１ｎｇ，样品最小检出浓度是：水０．００１ｍｇ／Ｌ，稻米和土壤０．０１μｇ／ｇ，稻草、谷壳、水浮莲和罗非鱼为０．００８μｇ／ｇ。     

Improved detection of toxic chemicals using bioluminescent bacteria

A sensitive, rapid and simple bioluminescent (BL) assay using bioluminescent bacteria to detect the toxic activity of several chemicals is described. This assay is based on the measurement of inhibition of light production of a bioluminescent bacterial strain, isolated from seawater, in the presence of different toxins like heavy metals, organic chemicals, such as benzene, toluene, ethylbenzene, xylene (BTEX) and a wide range of pesticides in environmental samples. The improvement with respect to other commercial and non-commercial bioluminescent assays consists of the possibility to work at room temperature without the need to thermostat, thus allowing the use of simpler and low cost instruments, or to improve the assay using a microplate format, which makes it possible to analyse several samples also continuously for several hours. Using lyophilised bacteria, the assay is performed in less than an hour, without any bacterial cultivation, which makes the test suitable for rapid and sensitive evaluation of chemical pollutants in environmental samples.     

Simultaneous determination of imidacloprid, carbendazim, methiocarb and hexythiazox in peaches and nectarines by liquid chromatography-mass spectrometry

A liquid chromatographic (LC) atmospheric pressure chemical ionization mass spectrometric (MS) method is described for determining imidacloprid, carbendazim, methiocarb and hexythiazox in peaches and nectarines. The samples were extracted with ethyl acetate and anhydrous sodium sulfate. Recoveries yield for spiking samples were ranged from 64±9% (R.S.D) for carbendazim to 108±14% (R.S.D.) for hexythiazox at the concentration of 0.1 mg kg⁻¹ (n=5). The correlation coefficients were greater than 0.998 over the range between 0.02 and 2 mg kg⁻¹. The limits of quantitation (LOQ) were 0.02 mg kg⁻¹ for all the pesticides. The applicability of the method to detect and quantify imidacloprid, carbendazim, methiocarb and hexythiazox was demonstrated successfully in 159 peach and nectarine samples obtained from an agricultural co-operative. The calculation of the estimated daily intakes (EDI) from these data showed that contribution of fruits to dietary intakes were much lower than acceptable daily intakes (ADI) proposed by international agencies.     

化学发光联用技术在兽药残留分析中的应用进展

本文对近年来化学发光联用技术在兽药残留分析中的应用进展进行了评述,主要包括化学发光免疫分析、分子印迹-化学发光分析、微流控芯片-化学发光检测等,引用文献31篇.     

Evaluation of automated and manual hot-splitless,cold-splitless (PTV), and on-column injection technique using capillary gas chromatography for the analysis of organophosphorus pesticides

Three different injection modes were compared for the analysis of organophosphorus pesticides. Differing results were found for several compounds depending on their chemical structure and thermostability. The programmed temperature vaporizing injector used in this study seemed to be the most promising sampling device for pesticide residue analysis in biological samples.     

高效液相色谱法测定水体系中N—（2,4—二甲苯基）—N‘—甲基甲脒盐酸盐

本文研究了用高效液相色谱法测定水体中单甲脒盐酸盐的分析方法，峰高定量，标准曲线的线性范围为０－１０００ｍｇ／Ｌ，回收率在８７％－９８％之间，直接进样分析检测限为０．３５ｍｇ／Ｌ。此方法已应用于细胞反应中单甲脒盐酸盐的测定。