电感耦合等离子体质谱(ICP-MS)法结合化学计量学分析比较6种松针中无机元素的含量

摘 要 为研究甘肃地区松针中无机元素的含量,探究不同品种松针中无机元素的差异,采用HNO3(65%)对松针样品进行微波消解,电感耦合等离子体质谱(ICP-MS)法测定甘肃两地区6种松针中28种无机元素的含量,结合主成分分析以及偏最小二乘判别分析对松针地区差异进行判别;结果显示松针中无机元素含量丰富,其中Na、Mg、Al、K、Ca、Fe、Zn、Mn、Sr等元素在不同品种松针中均有较高含量,主成分分析结果显示共有7个主成分,累积贡献率达到92.58%,偏最小二乘判别分析显示两地区6种松针在地区上可被明显分开,其中Mg、Fe、Zn、Mn、Sr、K 6种元素为造成地区差异的主要元素。实验结果表明松针中元素种类丰富,人体必需微量元素含量较高,且不同地区松针在地区上具有一定的一致性和特异性。     

鱼肉样品中的手性多氯联苯对映体的分离测定研究

该文建立了鱼肉样品中7种手性多氯联苯(PCB 45,PCB 91,PCB 95,PCB132,PCB 136,PCB 149和PCB 174)对映体的分离测定方法。样品经快速溶剂萃取技术萃取后,浓缩液经过凝胶渗透色谱除脂及大分子物质后再依次通过酸性硅胶柱、复合硅胶柱净化和碱性氧化铝柱分离得到PCBs组分。在气相色谱-质谱(GC-EI/MS)上对比研究了Bate Dex-325,CP-Chirasil,BGB-172SE,Chirasil-Dex和Cyclosil-B手性色谱柱的拆分效果,发现7种手性PCBs在Cyclosil-B毛细管柱上的分离效果最好,其分离度为0.8~2.3,可以实现基线分离。在优化色谱条件下,7种手性PCBs在10~200μg·L-1浓度范围内线性良好,相关系数为0.998~1.000,方法检出限(S/N=3)为0.4~5.0 ng·g-1。在高、低2个加标水平下,7种手性PCBs的回收率为89.2%~114%,相对标准偏差为0.3%~2.1%,表明方法灵敏度高、回收率好、准确度高。采集广东电子垃圾拆解污染区鱼类样品验证方法的适用性,结果显示鱼肉样品中均检出7种手性PCBs,3种鱼肉样品中7种手性PCBs的总浓度为386.7~602.8 ng·g-1。对3种鱼肉组织中7种手性PCBs的EF值进行测定,发现PCB 45,PCB 91,PCB 95,PCB 132,PCB 136和PCB 174的EF值与标准品具有显著差异,表明这些手性PCBs在鱼类体内可能具有对映体选择性富集和代谢作用,此外PCB 45,PCB 91,PCB 95,PCB 132和PCB136在3种鱼肉组织中的分布特征相似,而PCB174的EF值在乌鳢体内大于标准品,而在鲮鱼、鲫鱼体内却小于标准品,表明PCB174在乌鳢和鲮鱼、鲫鱼体内的选择性代谢过程可能相反。     

测试因素对一次性医用口罩通气阻力的影响

针对一次性医用口罩(DMMs)通气阻力测试结果不稳定情况,从测试设备稳定性、气体流量、样品不同位置、气流方向、预处理、测试时间方面展开了研究。结果表明,气体流量、样品不同位置和预处理对口罩的通气阻力有较大影响,测试时间和气流方向对口罩通气阻力无明显影响。研究结果对各生产厂商开发优异DMMs及生产过程质量控制有重要意义。     

等度反相高效液相色谱法测定熊胆中磷脂类化合物

 摘要：建立了一种分离、测定磷脂酰胆碱（PC）、磷脂酸（PA）、心磷脂（CL）和磷脂酰甘油（PG）的等度RP-HPLC法。色谱条件为：在P-EC18柱上,用V（甲醇）：V（乙腈）：V（水）＝79:8:13的溶液作流动相,以2.0mL/min的流速进行等度洗脱,紫外检测波长205nm,谱带宽5nm。以熊胆为样品,经预处理后用所建立的方法进行分析,结果表明：6个熊胆样品中PC的质量比差别较大;PA的质量比除2号样品较低外,其余相近;PG除2号样品外都能检出,其中6号样品中PG的质量比稍大。PC的平均回收率为89     

水合氧化钌对铂电催化剂上甲醇电氧化反应的促进作用

以多壁碳纳米管(MWCNTs)为载体,制备了Pt载量为20%的Pt-(RuOxHy)m/MWCNTs催化剂(m为Ru/Pt原子比),在m≤0.4时考察了不同电势区间循环伏安预处理对其催化性能的影响.水合氧化钌(RuOxHy)的存在明显提高了Pt催化剂抗CO毒化的能力,而在甲醇电氧化反应中Pt的质量比活性(MSA)随样品中m值增大呈先升后降趋势.经低电势区间(-0.20～0.46 V vsSCE)预处理稳定的催化剂中,Pt-(RuOxHy)0.10/MWCNTs样品中Pt的甲醇电氧化反应的MSA提高至相应单组分Pt/MWCNTs的9倍.将预处理电势区间扩展到高电势(即-0.20～0.96 V VS SCE)会造成钌组分溶解流失,导致催化剂抗CO毒化能力下降.在经过高电势区间的预处理后,Pt-(RuOxHy)0.20/MWCNTs对甲醇电氧化反应呈现出最高的催化活性,为单组分Pt催化剂的1.4倍.这些结果证实,水合氧化钌是Pt电催化剂的有效助剂.     

微流控芯片分析系统中硅胶整体柱和膜滤复合预处理单元的构建

以改性C18反相硅胶整体柱为微流控芯片分析系统中固相萃取介质材料, 构建不同功能单元的样品预处理微分析系统, 实现了血清样品中痕量盐酸多巴酚丁胺的富集. 初步构建了单一改性硅胶微柱固相萃取预处理单元, 测试得到了改性硅胶整体柱对血清中痕量盐酸多巴酚丁胺的平均富集倍数为77.2, RSD为12.35％. 为了提高测试的精密度, 进而设计含膜复合式预处理芯片, 探讨了不同预处理单元对血清样品中痕量盐酸多巴酚丁胺富集效率的影响, 优化设计了外接式硅胶整体柱-亲和膜微芯片固相萃取预处理单元, 复合式的反相硅胶整体柱对血清中微量盐酸多巴酚丁胺的平均富集倍数提高到89.4, RSD为4.37％. 结果显示了该预处理单元在血清中痕量药物富集的可行性和有效性.     

样品预处理与实时直接分析质谱的联用技术及应用

近年来,与实时直接分析质谱(DART-MS)相结合的样品预处理技术发展迅速,使得对复杂生物、环境、法医学、食品、个体小生物以及单细胞样品中的分析物进行直接分析成为可能。然而固体基质内部分析物检测困难、痕量分析物检测性能不佳已成为限制DART-MS进一步发展的关键问题。针对这些问题,多年来,研究人员在不同领域对样品预处理与质谱联用进行了多种尝试。该文以固相萃取(SPE)、分散固相萃取(DSPE)、搅拌棒吸附萃取(SBSE)、固相微萃取(SPME)、机械化学提取(MCE)和微波提取(MAE)等样品预处理技术为例,对不同研究领域中样品预处理技术与DART-MS联用的研究成果进行了综述,并对未来的发展趋势进行了展望。希望该综述能为开发与DART-MS联用的新型样品处理技术提供参考和帮助。     

一种基于近红外光谱技术的不同品种及掺假三七的无损鉴别分析研究

基于近红外光谱技术与化学计量学方法,提出了一种不同品种及掺假三七的快速无损鉴别方法。分别采集景天三七、菊三七、血三七、田三七完整、粉末及掺假样品的近红外光谱,采用单一和组合预处理方法消除光谱中的干扰,筛选出最佳的预处理方法;结合主成分分析法建立不同品种以及掺假三七样品的鉴别模型。结果表明：结合主成分分析,采用原始光谱即可实现粉末及掺假样品的100%鉴别分析,而完整样品由于受到物理性状的干扰,其原始光谱数据的品种鉴别率仅为9.38%;而经连续小波变换预处理后可达93.75%。采用组合预处理方法可以进一步消除光谱存在的多种干扰,显著提高完整样品的鉴别准确性,采用去偏移 + 一阶导数、去偏移+连续小波变换以及二阶导数+标准正态变量变换预处理方法预处理后,完整样品的鉴别准确率达到了93.75%。以上结果表明,采用近红外光谱技术与化学计量学方法可有效实现对不同品种以及掺假三七的快速无损鉴别分析。     

炭化过程对铁基费托合成催化剂强度和结构的影响

以模型费托合成Fe基催化剂为研究对象,在纯CO气氛中对催化剂进行不同时间的预处理,采用多种手段对预处理后催化剂的物理化学性质和抗磨损能力进行了表征。结果表明,在预处理初期,随着预处理时间的延长,催化剂的炭化程度显著提高,伴随着催化剂比表面积的降低和颗粒粒径的减小,而催化剂的抗磨损能力逐渐提高。当预处理时间超过72 h后,继续延长预处理时间,催化剂的炭化程度不再增加,而积炭程度逐渐增加,伴随着催化剂比表面积和颗粒粒径的增加,催化剂的质量也同时增加,并导致催化剂的抗磨损能力逐渐降低。     

加速溶剂萃取-气相色谱-串联质谱法测定松针中16种有机氯农药残留方法的中心组合设计优化

采用加速溶剂萃取-气相色谱-串联质谱法测定松针中16种有机氯农药的残留量,并对萃取条件进行了优化。在气相色谱分离中用DB-5MS石英毛细管柱为固定相,在质谱分析中采用总离子扫描监测模式。16种有机氯农药在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.3~2.8μg·L-1之间。方法用于松针样品分析,加标回收率在80.9%~99.2%之间,测定值的相对标准偏差(n=7)在2.9%~8.4%之间。     

Monitoring polychlorinated biphenyls in pine needles using supercritical fluid extraction as a pretreatment method

This paper reports on the first use of supercritical fluid extraction (SFE) of polychlorinated biphenyls (PCBs) from pine needles. Supercritical carbon dioxide was used as extraction fluid, and exhibited good extraction efficiencies and recoveries (>90%). GC-MS (selected ion monitoring mode) achieved both accurate identification and quantification of the PCBs. Compared with traditional time consuming multi-step sample preparation methods, SFE with carbon dioxide is easier to perform, and is a feasible alternative extraction procedure for the monitoring of PCBs in pine needle samples.     

Interference of Transformer oil Matrices to the Internal Standards on PCB Quantification

Abstract

Polychlorinated biphenyls (PCBs) are toxic, perssstent, global environmental contaminants which were formulated as complex mixtures of congeners. Many methods have been developed in the past to analyze PCB in transformer oil samples for regulatory purposes. The most important consideration in the cleanup procedure is the ability to remove the oil from the sample matrix, since trace amount of oil will interfere with the subsequent GC-MS analysis. Electron capture detection (ECD) has been the most common method for gas chromatographic analysis of PCBs because of its high sensitivity toward halogenated compounds. ECD can also respond to some non-PCB compound resulting in biased concentrations of PCB. In this work, a two-stage cleanup method, using DMSO liquid/liquid extraction and HPLC column chromatography. has been applied to two types of transformer oil. Five internal standards have been selected to show their performance in the presence of different oil matrices. The comparison of the PCB quantification at different conditions for GC-MS and GC-ECD will be demonstrated.     

同位素稀释-HRGC-LRMS法测定环境样品中二噁英类多氯联苯

多氯联苯(PCBS)是一类具有209种同类物的高毒性、难降解、强脂溶性和生物累积性的持久性有机污染物,自从1966年Jensen首次在鹰和鲱鱼中发现PCBs后,现在已在世界各地不同的环境介质中都发现有PCBs的存在。早在20世纪70～80年代国际上就开发了一些环境样品中PCBs的分析方法。但这些方法基本上基于某一种或几种商业PCBs混合物来对环境中多氯联苯类物质进行评价的,由于该商业PCBs是数十种或上百种PCBs的混合物,所评价的对象中PCBs的结果并不能准确反映其环境危害性。另一     

Analytical quality control for the determination of polychlorobiphenyls in environmental matrices

Analytical quality control procedures for ensuring reliable data in the determination of PCBs in environmental matrices are described. Several extraction procedures of PCBs from sediment samples are critically compared and recovery and reproducibility for PCBs determination in sediment and cod liver oil samples are evaluated. Extraction by 1:1n-hexane/acetone mixture in an ultrasonic bath and by supercritical fluids generally give a quantitative recovery and a coefficient of variation lower than 15%, while extraction by a Soxhlet system does not give such good results and requires much longer extraction times. Certified reference materials available from three international organizations, namely the Standards, Measurements and Testing programme of the European Union, the USA National Institute of Standards and Technology and the National Research Council of Canada were used. Finally, the on-going European Union QUASIMEME programme aimed at improving the analytical quality of marine pollution monitoring measurements of European laboratories is addressed.     

A new non-destructive method for chemical analysis of particulate matter filters: the case of manganese air pollution in Vallecamonica (Italy)

Total Reflection X-ray Fluorescence (TXRF) is a well-established technique for chemical analysis, but it is mainly employed for quality control in the electronics semiconductor industry. The capability to analyze liquid and uniformly thin solid samples makes this technique suitable for other applications, and especially in the very critical field of environmental analysis. Comparison with standard methods like inductively coupled plasma (ICP) and atomic absorption spectroscopy (AAS) shows that TXRF is a practical, accurate, and reliable technique in occupational settings. Due to the greater sensitivity necessary in trace heavy metal detection, TXRF is also suitable for environmental chemical analysis. In this paper we show that based on appropriate standards, TXRF can be considered for non-destructive routine quantitative analysis of environmental matrices such as air filters. This work has been developed in the frame of the EU-FP6 PHIME (Public Health Impact of long-term, low-level Mixed element Exposure in susceptible population strata) Integrated Project (www.phime.org). The aim of this work was to investigate Mn air pollution in the area of Vallecamonica (Italy).     

Development and validation of a solid-phase microextraction method for the analysis of volatile organic compounds in groundwater samples

Summary Solid-phase microextraction is a relatively recent extraction technique for sample preparation. It has been used successfully to analyse environmental pollutants in a variety of matrices such as soils, water and air. In this work, a simple and rapid method for the analysis of volatile organic and polar compounds from polluted groundwater samples by SPME coupled with gas chromatography (GC) is described. Different types of fibres were studied and the extraction process was optimised. The fibre that proved to be the best to analyse this kind of samples was CAR-PDMS. The method was validated by analysis of synthetic samples and comparison with headspace—GC. The optimised method was successfully applied to the analysis of ground-water samples.     

Method development for the analysis of polybrominated diphenyl ethers, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzo-furans in single extract of sediment samples

A comprehensive method was developed for quantitative analysis of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) in one single extract of environmental samples. The sample preparation procedure included two fractionation steps using silver nitrate silica chromatography to separate PBDEs from PCBs and PCDD/Fs and florisil column to separate PCBs from PCDD/Fs. Acidic silica, acidic alumina and gel permeation chromatography (GPC, for PCBs) or activated carbon column (for PCDD/Fs) were used for further clean-up. The sample extracts were analyzed by using high-resolution gas chromatography/high-resolution mass spectrometry. The entire method was validated from the analysis of mixed standards of PBDEs, PCBs and PCDD/Fs (n = 3); the analysis of certified reference biota (WMF-01). The method was applied for the analysis of 10 sediment samples collected from Haihe River and Dagu Drainage River in Tianjin City. No significant PBDEs pollution was found in the areas.     

The Effect of Temperature on GPC for the Separation of PCBs from Transformer Oil and Subsequent Analysis by GC-MSD

Abstract

The analysis of PCBs often involves lengthy and expensive cleanup procedures to remove interferences associated with environmental sample matrices. Gel permeation chromatography (GPC) has proven to be a useful tool in removing many of these interferences from environmental samples, especially from difficult matrices such as oils, lipids and sediments. This paper describes the effect of temperature upon the GPC column in separating PCBs from transformer oil and its implication on GC-MS analysis.     

Stir bar sorptive extraction for trace analysis

Stir bar sorptive extraction (SBSE) was introduced in 1999 as a solventless sample preparation method for the extraction and enrichment of organic compounds from aqueous matrices. The method is based on sorptive extraction, whereby the solutes are extracted into a polymer coating on a magnetic stirring rod. The extraction is controlled by the partitioning coefficient of the solutes between the polymer coating and the sample matrix and by the phase ratio between the polymer coating and the sample volume. For a polydimethylsiloxane coating and aqueous samples, this partitioning coefficient resembles the octanol-water partitioning coefficient. In comparison to solid phase micro-extraction, a larger amount of sorptive extraction phase is used and consequently extremely high sensitivities can be obtained as illustrated by several successful applications in trace analysis in environmental, food and biomedical fields. Initially SBSE was mostly used for the extraction of compounds from aqueous matrices. The technique has also been applied in headspace mode for liquid and solid samples and in passive air sampling mode. In this review article, the principles of stir bar sorptive extraction are described and an overview of SBSE applications is given.     

GC/MS determination of incidental PCBs in complex chlorinated-hydrocarbon process and waste streams

An electron-impact gas chromatography/mass spectrometry method using selected ion monitoring for the determination of incidental polychlorinated biphenyls in complex chlorinated-hydrocarbon samples is described. Ions in the molecular-ion cluster for each degree of chlorination (from monochloro- to decachlorobiphenyl) are monitored. Individual PCB isomers are used as standards. Validation data collected for several complex chlorinated-hydrocarbon matrices in three different laboratories had a relative precision (2sigma) of 20% with a limit of detection (3 x standard deviation of base-line noise) of 5 ppm for a single isomer at any degree of chlorination. The method has been used for the determination of incidental PCBs in more than 1000 samples from more than 30 different chlorinated-hydrocarbon sample matrices.