Enrichment sampling methods for wine discrimination with gas sensors

A comparison between two sampling methods based on sample concentration (purge and trap (PT) and solid-phase micro-extraction (SPME)) applied to gas sensors (electronic nose) for wine discrimination is performed. Two different traps have been used in the Tekmar 3100 purge and trap concentrator: trap containing Tenax and Tenax/silica gel/charcoal. Four different types of fiber coating have been used for SPME method: 100 μm polydimethylsiloxane (PDMS), 65 μm polydimethylsiloxane/divinylbenzene (PDMS/DVB), 85 μm polyacrilate and 75 μm carboxen/polydimetilsiloxane (CAR/PDMS). The cell containing a tin dioxide multisensor was mounted inside the gas chromatograph (GC) oven, connected to the injector by replacing the chromatographic column. In this way, the GC injection port has been used to connect the purge and trap and fiber holder to sensors cell. Samples of five different wines elaborated with the major varieties of DO Vinos de Madrid were used for testing the discrimination capability of the systems. Multivariate analyses as principal component analysis (PCA) and artificial neural netwoks (ANN) have been applied to the data to discriminate among the different wine samples. Results show that purge and trap technique provide better response. Tenax trap and 85 μm polyacrilate fiber obtained the highest success rate in classification.     

An intercomparison for NIRS and NYU passive thoron gas detectors at NYU

An intercomparison on thoron ((220)Rn) measurement was carried out between National Institute of Radiological Sciences, Japan (NIRS), and New York University School of Medicine, USA (NYU). The measurements of (220)Rn concentration at NIRS and NYU were performed by using the scintillation cell method and the two-filter method, respectively, as the standard measurement method. Three types of alpha track detectors based on passive radon ((222)Rn)-(220)Rn discriminative measurement technique were used: Raduet and Radopot detectors were used at NIRS, and four-leaf detectors were used at NYU. In this study, the authors evaluated (220)Rn concentration variation in terms of run for exposure, measurement method, and exposure chamber. The detectors were exposed to (220)Rn gas with approximately 15 kBq m(-3) during the period from 0.75 to 3 d. As a result, the variation of each measurement method among these exposure runs was comparable to or less than that for the two-filter method. Agreement between the standard measurement methods of NIRS and NYU was observed to be about 10%, as is the case with the passive detectors. The Raduet detector showed a large variation in the detection response between the NIRS and NYU chambers, which could be related to different traceability.     

空气中1，2-二氯乙烷气体检测管的应用评估

采用5 L气体采样袋配制1,2-二氯乙烷标准气体系列，经气相色谱法测定建立定量评估标准曲线。分别配制低、中、高浓度空气加标样品，评价气体检测管检测结果的准确度和精密度。设计干扰实验验证气体检测管特异性。结果显示，气体检测管平均回收率98.0%～104.1%，相对标准偏差4.3%～5.3%。1,1-二氯乙烷等不干扰气体检测管显色。静态配气-气相色谱法适用于1,2-二氯乙烷快速检测的定量评估，经验证气体检测管定量结果准确稳定、特异性强。     

病原微生物快速检测电化学传感器最佳检测条件的实验研究

目的 探讨氧化锌(ZnO)溶胶-凝胶电化学生物传感器的电化学性能及液相检测影响因素.方法 自主构建电化学生物传感器,固载ZnO溶胶-凝胶的玻碳电极为工作电极;饱和甘汞Ag/AgCl电极为参比电极;铂电极为对电极.观测缓冲液不同pH值、不同扫描电位下修饰电极电化学行为的变化规律.结果 传感器修饰电极随着缓冲液pH值、扫描电位的变化而有明显的改变,当pH为7.4、扫描电位为0～0.6 v时,其电化学响应最强.结论 成功构建了ZnO溶胶-凝胶电化学生物传感器检测系统,并探索优化了电化学生物传感器检测影响因素.     

磷化氢气体检测管的研制与评价

当含有磷化氢的空气通过以硅胶为载体吸附氯化汞与甲基红的混合溶液制成的指示粉时,指示粉由粉红色变成白色,根据检测管中变色柱的长度,得出磷化氢的浓度,从而快速检测空气中磷化氢的浓度,据此研制出操作简单、携带方便、便于外出测定和大面积布点测定的磷化氢气体检测管。本检测管集采样与分析为一体,可快速对空气中磷化氢气体进行定性和定量。磷化氢浓度与检测管着色长度在0.1~10.0 ppm范围内呈线性相关。     

基于金属有机框架材料的传感器在真菌毒素检测中的研究进展

真菌毒素是广泛存在于谷物和饲料中的霉菌次级代谢产物,对公众健康构成严重威胁,引起了全世界广泛的关注。由于传统的检测方法复杂且操作难度高,迫切需要开发简单、快速、方便且成本低、效益高的真菌毒素检测方法。基于金属有机框架（metal-organic frameworks,MOFs）材料的传感器对真菌毒素具有良好的检测能力,其操作简单、响应迅速、灵敏度高引起了人们的关注,在食品安全和风险评估方面展现出广阔的前景。本综述总结了基于金属有机框架材料的传感器检测真菌毒素的研究进展,为相关领域的研究人员提供参考。     

气相色谱-质谱联用法快速检测血清中敌鼠

目的应用气相色谱-质谱联用(GC-MS)法快速鉴定鼠药中毒生物样品的敌鼠成分。方法用乙酸乙酯-乙醇(2 1,V/V)混合液萃取病人血清中疑似成分,用GC-MS仪,HP-5MS交联弹性毛细管石英柱(30.00m×0.25mm×0.25μm)进行分离,以氦气为载气进行质谱分析,以质谱专用数据库(NIST98)鉴定。结果经质谱库检索分析得出该病人血清中疑似成分离子谱图与敌鼠钠标准质谱图的匹配度为96%,从而确定该病人血清中含有敌鼠成分,与临床症状符合。结论本方法可快速定性检测血清的敌鼠成分,且准确性和灵敏度较高,操作简便,还可同时定性其他鼠药成分,具有较高的临床实用价值,在急性化学中毒事故快速处理中将发挥极为重要的作用。     

便携式红外气体分析仪在线快速检测几种有毒有害气体

目的:利用MIRAN SapphlRE便携式红外气体分析仪对数种有害气体进行在线分析.方法:采用全谱扫描方式对数种有害气体进行在线检测.结果:可利用便携式红外气体分析仪对氨、二氧化硫、丙酮、丁酮、乙酸乙酯、氯仿、苯、甲苯、甲醇、乙醇、异丙醇等有害气体可进行快速的在线检测,不能对砷化氢、氯化氢、氰化氢、硫化氢进行快速在线检测.结论:使用便携式红外气体分析仪可以对数种有害气体进行快速的在线检测,方便、快速、准确.     

光声痕量气体分析仪在熏蒸气体检测上的应用

目的监控熏蒸气体泄漏。方法光声痕量气体分析仪在线实时监控。结果系统投入工作后,运行稳定,多次通过短信发送提前预警,避免了工作人员在取瓶时中毒事件的发生。结论在线式痕量熏蒸气体分析系统为保证港口进出口货物的卫生检疫工作有序进行及熏蒸服务人员的人身安全提供了新的解决方案。     

顶空气相色谱法同时测定水中多种挥发性卤代烃

〔目的〕建立同时测定水中多种挥发性卤代烃的方法。〔方法〕采用顶空气相色谱法。〔结果〕8种卤代烃的线性方程相关系数为 0 .9982 % -0 .9996% ,检出限为 0 .0 2 -0 .2 5 μg L ,样品加标平均回收率为 95 .8% -10 2 .4%。〔结论〕本法具有干扰小、灵敏度高、检出限低、线性范围宽、操作简便、快捷、结果准确可靠的优点 ,适合水中多种卤代烃的检测分析。     

气相色谱-质谱联用法测定塑料稳定剂中的三甲基氯化锡

目的 建立塑料稳定剂中三甲基氯化锡(TSC)的测定方法.着重研究气相色谱-质谱联用(GC-MS)条件的选择、方法的回收率、线性范围、检出限及精密度等指标.方法 样品中的TSC经硼氢化钾衍生氢化、正己烷提取后,再用GC-MS法进行检测.结果 TSC含量在4.8～1 207.0 mg/kg范围内呈线性关系,相关系数(r)=0.999 9,最低检出限为1.2 mg/kg.方法 的相对标准偏差(RSD)=2.7%～9.0%.回收率为95.4%～96.6%.结论 该方法能准确测定各种塑料稳定剂中TSC的浓度,各项指标符合<工作场所空气中毒物检测方法的研制规范>的要求,值得推广应用.     

饮用水中亚硝胺类物质气相色谱质谱法检测应用

目的 建立优化固相萃取-气相色谱质谱（SPE-GC-MS）同时检测饮用水中9种亚硝胺类物质方法条件。 方法 通过固相萃取前处理以及优化后的气相色谱质谱法对样品净化浓缩,同时通过样品回收率、精密度、方法检出限（MDL）、测定下限、标准曲线对建立的方法进行验证。结果 9种亚硝胺的保留时间在9.819~20.541 min,在10~1 000 μg/L均线性范围良好（R²>0.999）,MDL在2.27~6.20 ng/L,低浓度（50 ng/L）加标回收率为62.32%~89.71%,中（100 ng/L）、高浓度（200 ng/L）加标回收率为73.43%~109.66%,相对标准偏差（RSD）均<10,自来水加标回收率为74.62%~102.74%。结论 建立的SPE-GC-MS法满足检测饮用水中9种亚硝胺类物质的要求。     

GC-MS检测蔬菜有机磷农药残留的效果分析

目的:用比较法对气相色谱-质谱法检测蔬菜农药残留的效果进行综合分析。方法:用气相色谱-质谱法对已知的5种农药标准品连续稀释计算出检出限,并随机抽取本地菜农种植的四种蔬菜进行农药残留量检测。同时用气相色谱法同步进行比较试验。结果:两种方法比较,气相色谱-质谱法具有更高的灵敏度和准确度,差异有统计学意义(P<0.05)。对蔬菜残留农药的检测结果表明GC-MS在蔬菜农残检测中具有更广泛的用途。结论:GC-MS在检测蔬菜农药残留方面具有更好的效果。     

Determination of methyltetrahydrophthalic anhydride in air using gas chromatography with electron-capture detection.

Methyltetrahydrophthalic anhydride (MTHPA) stimulates the production of specific IgE antibodies which can cause occupational allergy even at extremely low levels of exposure (15-22 micrograms/m3). Safe use in industry demands control of the levels of exposure causing allergic diseases. Thus, the air monitoring of MTHPA is very important, and sensitive methods are required to measure low air concentrations or short-time peak exposures. This paper outlines the use of silica-gel tubes for sampling airborne MTHPA vapour, followed by analysis using gas chromatography with electron-capture detection. No breakthrough was observed at 113, 217, 673 and 830 micrograms/m3 (sampling volume 30, 60, 60 and 20 l, respectively; relative humidity 40-55%). Concentrations > 1.0 microgram/m3 could be quantified at 20-min sampling with a sampling rate of 1 l/min. The present method can also be applied to measurements of exposure to hexahydrophthalic and methylhexahydrophthalic anhydride. The risk of MTHPA exposure in two condenser plants was also assessed by determining MTHPA levels in air of the workplace. In conclusion, our method was found to be reliable and sensitive, and can be applied to the evaluation of MTHPA exposure.     

Fast gas chromatography for air monitoring: limits of detection and quantitation.

Gas chromatography has the potential to be a very fast method of air monitoring in the workplace and the community. The use of "fast" gas chromatographic (GC) instrumentation and methods may allow the completion of analyses in less than 10 sec when a flame ionization detector is used and in less than 30 sec when an electron capture detector is used. In this study, the fast GC system was evaluated as an air-monitoring tool for 41 different organic vapors at concentrations as low as 0.1 ppb.     

蔬菜、水果中有机磷农药多残留同时测定的气相色谱法研究

目的:建立同时测定蔬菜、水果中多种有机磷农药残留的气相色谱分析方法。方法:蔬菜、水果匀浆后经混合溶剂提取,固相萃取柱净化,气相色谱FPD检测。结果:该方法各种有机磷农药的相关系数r均在0.99以上,平均回收率为60.6%~108.9%,相对标准偏差RSD为4.57%~19.8%,最小检出量为1~50 ng。结论:该方法提取完全,净化彻底,定量准确,操作简便,满足多种有机磷农药残留的同时测定。