纺织品中五氯苯酚残留量测量不确定度评定

采用气相色谱法测定纺织品中残留的五氯苯酚含量,对整个测量过程的不确定度来源进行了分析,并对不确定度各个分量进行了评定与合成。当五氯苯酚测定结果为0.570mg/kg时,扩展不确定度为0.054mg/kg,并给出了检测结果不确定度表达式。     

气相色谱内标法测定生活饮用水中氯酚的不确定度评定

对气相色谱内标法测定生活饮用水中氯酚类化合物结果的不确定度进行评定,探讨了影响不确定度的关键因素。检测过程中测量不确定度来源包括取样体积、标准物质、标准使用液的配制、标准曲线的拟合、重复性测定。以2,4,6-三氯苯酚为例,当水样中2,4,6-三氯苯酚测定结果为1.00μg/L时,测定结果在95%置信区间时的相对标准不确定度为0.027 0(k=2)。结果表明,由标准溶液、系列标准工作溶液的配制、标准曲线拟合引入的不确定度分量较大,内标的使用可有效消除样品处理操作和其它因素引起的误差,提高测量的准确性。     

气相色谱-质谱法测定食品接触材料中五氯苯酚含量的不确定度评定

对气相色谱-质谱联用法测定食品接触材料中五氯苯酚含量过程中可能引入的不确定度进行了分析和评定.通过实验数据计算得出食品接触材料中五氯苯酚含量的不确定度,当置信水平为95%,包含因子k=2时,其相对扩展不确定度为4.04%.通过对不确定度的分析.指出在检测过程中质量控制的关键在于标准物质的浓度和气相色谱分析过程,并提出了...     

棉类纺织品中痕量五氯酚的液相色谱-同位素稀释质谱法测定及不确定度评定

应用液相色谱-同位素稀释质谱联用法(LC-IDMS)对棉类纺织品中的痕量五氯酚(PCP)残留进行测定.采用稀硫酸酸化的正己烷提取棉类纺织品样品中的残留五氯酚,以5 mmol/L醋酸铵-甲醇(体积比20 : 80)为流动相、在C18色谱柱上进行分离,结合电喷雾电离离子化技术,在负离子模式下进行质谱定量分析,以PCP-13C6同位素标记物作内标,以m/z 264.8和270.9为定量离子对.方法的定量下限为0.005 μg/g,在0.099、0.244、0.494 μg/g 3个添加水平的平均回收率为96% ～104%,相对标准偏差为0.81% ～1.4%,并对该方法的不确定度来源进行了评定.方法准确、可靠,适用于纺织品中痕量五氯酚残留的测定及方法验证.同时可以作为对该类国家标准物质的定值手段,用于标准物质的定值.     

气相色谱-质谱联用法测定水果中环氧七氯残留量的不确定度评定

对《蔬菜、水果中农药残留量的气质联用测定方法》测定水果中环氧七氯农药残留量的不确定度进行了评定,分析和量化了影响测定结果的不确定度分量,将不确定度分量合成,得到环氧七氯农药残留量的扩展不确定度为0．25μg／g。     

纺织品、皮革及其制品中五氯苯酚残留量的气相色谱-质谱法测定

介绍应用气相色谱-质谱法测定纺织品、皮革及其制品中防霉剂五氯苯酚的残留量,试样经硫酸溶液酸化后用正己烷提取,用气相色谱-质谱选择离子测定。方法简便、快速、灵敏,检出限20μg／kg,添加回收率86．7％～93．1％,变异系数4．1％～5．9％。     

木材及木制品中残留五氯酚的气相色谱测定法

建立了木材及木制品中五氯酚的气相色谱测定法.样品经丙酮提取,浓硫酸净化,正己烷萃取后吹干,于0.1 mol/L K2CO3的介质中用乙酸酐衍生,采用HP-5毛细管气相色谱柱分离, ECD检测器进行检测.在0.01～50 mg/L的范围内线性关系良好;检出限为0.005 mg/kg;相对标准偏差为2.6%～3.6%;回收率在89.3%～103.5%之间.方法具有灵敏、简便、准确的特点.     

加速溶剂萃取-气相色谱法测定木材中五氯酚残留量

提出了气相色谱法测定木材中五氯酚残留量的方法。样品用乙醇经加速溶剂萃取仪在100℃静态萃取10 min。采用DB-5毛细管柱分离,电子捕获检测器测定五氯酚含量。五氯酚的质量浓度在0.01～50 mg·L^-1范围内与峰面积呈线性关系,方法的检出限（3S/N）为0.01 mg·kg^-1。以木材样品为基体,进行加标回收试验,回收率在94.2%～98.2%之间,测定值的相对标准偏差（n=6）小于4%。     

Development of a method for the rapid determination of pentachlorophenol in leather using supercritical fluid extraction with in situ derivatization

Pentachlorophenol (PCP) was extracted from leather with supercritical carbon dioxide and in situ acetylated under static SFE conditions in the presence of triethylamine. During the dynamic extraction step, the derivatives were removed from the matrix and collected with either a pure liquid (light petroleum) or a liquid-solid (light petroleum-solid sorbent (C18, alumina, Florisil or Celite)) trap. To prevent restrictor plugging, a suitable restrictor was designed. The clean-up of the extracts was optimized in this study. Different internal standards were tested and it was shown that not all of them were usable. The SFE results were compared with those obtained by Soxhlet extraction with methanol. With SFE instead of conventional Soxhlet extraction, the overall time required for determination of PCP in leather can be reduced from about 2 days to approx. 3 hours.     

气相色谱-质谱联用法测定乐果的不确定度评定

本文以测定样品中乐果的含量为例,评定了气相色谱-质谱联用法测定结果的不确定度.建立数学模型,分析各不确定度分量,将不确定度分量合成,并计算其测定结果的扩展不确定度.     

Simultaneous determination of pentachlorophenol and carbaryl in water

Summary A rapid method for the simultaneous determination of pentachlorophenol (PCP) and Carbaryl in water is described. A 1 liter water sample is extracted with hexane after acidification with concentrated H₂SO₄. After evaporation to a small volume, the extract is analyzed by gas chromatography-mass spectrometry, operating in the selected ion monitoring mode. Estimated detection limits are 0.08 g L^–1 for PCP and 0.11 g L^–1 for Carbaryl, with recoveries of 96% for PCP and 97% for Carbaryl.     

Determination of pentachlorophenol residues in wine and corks by solvent extraction methodology and specific gas chromatography detection

Summary A gas chromatographic methodology with selective detection is presented for the analysis in wines and corks of pentachlorophenol residues, which are suspected to be the most likely precursors of some off-flavours described in several wine samples. After derivatisation, pentachlorophenol acetate residues were monitored by electrolytic conductivity detection and/or mass spectrometric detection in the selective ion mode at m/z 264 and 266. Recoveries varied from 80 to 96% for wine samples fortified with 5 to 100 g l^–1 and from 83 to 91% for corks (fortified at 25 to 100 g kg^–1). The proposed methodology allowed for a determination limit of g l^–1 for wine and 10 g kg^–1 for corks.     

Direct GC determination of methylmercury chloride on HBr-methanol-treated capillary columns

Summary Gas chromatography with electron capture detection (GC-ECD) for the analysis of methylmercury choloride (MMC) using a packed column and a capillary column has been investigated. The columns were 2% silicone OV-227 Uniport HP glass column and a DB-17 capillary column, each pretreated by about ten injections of HBr-methanol solution. MMC was separated as a sharp peak by the HBr-teated column and determined directly by ECD without derivatisation. The mass spectrum of MMC indicated that halide exchange from chloride to bromide proceeded during separation. The minimum detectable concentrations were approximately 5 ng mL⁻¹ on the packed column, and 2 ng mL⁻¹ on the capillary. Calibration curves showed good linearity between 5–200 ng mL⁻¹ for the packed column, and between 2–200 ng mL⁻¹ for the capillary. Relative standard deviations of peak areas were 0.95% for the packed column and 0.43% for the capillary at the level of 100 ng mL⁻¹ in both cases. The column treatment technique was applicable to determination of methylmercury in fish samples.     

Quantification of residual monomer in polylactide by gas chromatographic internal standard method

An analytical method has been developed to quantitatively determine the residual lactide monomer in polylactide (PLA) using an internal standard method of gas chromatography (GC). The experimental results showed that diphenyl ether (DPE) was an appropriate internal standard for quantitative analysis of residual lactide in PLA. PLA and DPE were dissolved in dichloromethane and precipitated in hexane. At the same time, the residual lactide in PLA and DPE as an internal standard were extracted to hexane from the polymer solution. The resulting solution could be directly injected into a GC system. Therefore, the residual lactide was determined quantitatively using an internal standard method of GC. This method is practical for measuring the residual lactide content in PLA. When the lactide content is 5.0%, the relative standard deviation (RSD) of the measurements is 1.7%, while RSD is 6.9% at the low level of 0.4%, which indicates that the method is sufficiently precise.     

QuEChERS法提取水稻土壤中的五氯酚

用超声振荡与一种快速、简易、廉价、高效、可靠、安全的分离方法(简称QuEChERS)法相结合的技术研究水稻土壤中五氯酚的提取。就萃取剂、酸用量、提取方式、吸附剂种类以及吸附剂用量等因素对回收效率的影响作了比较。结果表明,最佳条件为:用10mL乙腈为提取液,2mL浓度为6mol/L的H2SO4酸化,加2mL正己烷,振荡30min,40℃超声1h,离心后上清液再选用20mgODS和200mg无水硫酸镁净化。在高、中、低3个不同浓度的土壤中,都可以稳定在75%～120%的回收率。     

火焰原子吸收法测定土壤中铜的测量不确定度评定

根据GB／T17138-1997规定的测量步骤对土壤中的铜进行了测定,对影响测定结果的各不确定度来源进行了分析,并对一个样品的测定结果进行了不确定度评定。     

Dispersive liquid-liquid microextraction and liquid chromatographic determination of pentachlorophenol in water

A simple and sensitive dispersive liquid-liquid microextraction method for extraction and preconcentration of pentachlorophenol (PCP) in water samples is presented. After adjusting the sample pH to 3, extraction was performed in the presence of 1% W/V sodium chloride by injecting 1 mL acetone as disperser solvent containing 15 μL tetrachloroethylene as extraction solvent. The proposed DLLME method was followed by HPLC-DAD for determination of PCP. It has good linearity (0.994) with wide linear dynamic range (0.1–1000 μg L⁻¹) and low detection limit (0.03 μg L⁻¹), which makes it suitable for determination of PCP in water samples.      

Solubility parameter determination of cationic surfactants by inverse GC

Summary The solubility parameters of cationic surfactants were obtained using the inverse gas chromatographic technique. The surfactants didodecyl dimethyl ammonium bromide, dioctadecyl dimethyl ammonium bromide and dodecyl pyridinium chloride were used as stationary phase and retention data of different probe solutes were measured at different temperatures. The results were analysed by the combination of Flory-Huggins and Hildebrand theories, and the solubility parameters of the surfactants were obtained in a range of temperatures between 80–120°C.