甲醛渗透管的研制

本文主要介绍了用ｗｈ聚四氟乙烯膜作为渗透材料制作甲醛渗透管的方法,并且针对所研制的渗透管的特性,影响渗透率的主要因素及渗透率的稳定性等方面进行了探讨。     

标准物SO_2、NO_2渗透管渗透率的适宜范围

环境空气自动监测系统(以下称“系统”)中采用SO_2、NO_2渗透管作为气体标准物,分别用于对二氧化硫监测仪、氮氧化物监测仪进行校准.现在国内各城市大多采用美国MONI TOR LABS公司的“系统”(或该“系统”的一次仪表部分).该“系统”中的ML—8550动态校准器,内部安置50℃SO_2、NO_2渗透管产生标气,对ML—8850型SO_2仪、ML—8840型NO_x仪进行每天一次的零点——单标点跨度自动核标;每月多点的人工动态校准.该校准器中使用渗透管的渗     

Hg-CEMS系统中元素汞发生器的溯源和质控方法研究

参考借鉴美国IEMGTP元素汞溯源协议中规定的4个溯源传递层级以及4种常用的成熟溯源质控方法,研究了在中国现有技术条件下,各种质控方法针对Hg-CEMS中元素汞发生器User generator进行质控的适用性。通过对不同质控方法的测试,显示通过可吸附元素汞的活性炭吸附管采样分析（美国EPA 30B方法）和通过汞渗透源两种对元素汞发生器进行质控的方法在中国目前是可行且科学、可靠的。同时对建立和完善中国的元素汞溯源协议和元素汞发生器质控方法提出了建议。     

加速溶剂萃取/气相色谱-质谱法测定小麦中多环芳烃

建立了小麦中8种多环芳烃的分析方法.样品通过加速溶剂萃取,经全自动在线凝胶渗透色谱-浓缩联用系统和硅胶柱净化,最后用GC-MS测定.实验中优化了加速溶剂萃取条件和凝胶渗透色谱净化条件.结果表明,在120℃用正己烷-丙酮(V∶V=1∶1)提取8min,萃取3次的提取效果最好,1000～1800s是凝胶渗透色谱净化的最佳收...     

十管发酵法测定水中总大肠菌群

目前,测定水中总大肠菌群多用国际上流行的多管发酵法,我国常用15管或12管发酵,工作量较大,消耗原材料较多。今通过试验建立了十管发酵法（简称该方法）,原理与多管发酵法相同,比五管发酵法的准确度高,适用于生活饮用水、水源水、地表水和废水中总大肠菌群的测定。     

甲醛法测定二氧化硫操作方法的改进

甲醛法测定二氧化硫时 ,按《空气和废气监测分析方法》进行操作 ,需准备两套比色管 ,并将Ａ管溶液倒入Ｂ管溶液中 ,立即混匀 ,操作步骤较为繁琐。其原因是显色反应需在酸性溶液中进行 ,为此应将Ａ管的碱性溶液倒入Ｂ管的强酸性ＰＲＡ溶液中 ,使混合液在瞬间呈酸性 ,利于显色反应进行 ,以免影响测定的精密度。今作了如下改进 ,即将原先容积为 1 0ｍＬ的Ａ管改用 2 5ｍＬ比色管 ,省去Ｂ管 ,而将Ｂ管的ＰＲＡ溶液用自动加液器以很快的速度压注入盛有样品或标准系列的Ａ管中 ,立即摇匀 ,使其得以瞬间混合。其余步骤均与《空气和废气监测分析方法…     

水质硫化物直接吸收显色法中前置气体分离管存在的缺点和替换方法

介绍了直接吸收显色法分析水质硫化物中,气体分离管在实际操作中存在的缺点和氢氧化钾溶液替换气体分离管的优点,并通过实验来论证替换的可行性。     

石墨炉原子吸收分光光度法测定饮用水中钡的实验研究

文章通过实验研究优化了一种石墨管原子吸收法测定饮用水中钡的方法。分别采用普通石墨管和ELC石墨管,通过优化灰化温度和原子化温度以及实际样品检测验证了方法的可行性。结果表明,采用普通石墨管检出限为4.69μg/L,相对标准偏差为9.5%,实际样品加标回收率为92%~100%;采用ELC石墨管检出限为1.90μg/L,相对标准偏差为8.7%,实际样品加标回收率为98%~101%,两种方法均可满足实验室饮用水中钡的测定要求。     

三氧化铬管的快速填充法

盐酸萘乙二胺比色法测定空气中氮氧化物,需配制三氧化铬-石英砂氧化管,一般用药匙将三氧化铬-石英砂一匙一匙地装入,因管内径较小,掉得多,进得少,装一个氧化管最快也需80 s。夏季时,空气湿度大,易受潮,需反复烘,时间则更长。今设计了一简易装置,装管48个,只用12 min20 s,不仅防止了三氧化铬粉尘对人体的毒害且速度快,大大提高了工作效率。用乳胶管(3 cm)将玻璃漏斗(直径约7 cm)和聚乙烯塑料管(10-20 cm)连接起来,下端再用5     

采样容器溶出氯离子对监测空气中氯化氢的干扰分析

试验了玻璃、聚乙烯、聚四氟乙烯等不同材质容器溶出氯离子对环境空气中氯化氢测定的影响,指出测定结果偏高的原因在于采用玻璃气泡吸收管,分析了玻璃材质溶出氯离子的原因,建议采用特制的聚四氟乙烯或聚乙烯吸收管采样。     

ASE—GPC—GC—MS快速分析土壤中的PAHs

建立了土壤中多环芳烃的气相色谱—质谱联用的快速检测方法。样品经过加速溶剂萃取、凝胶色谱净化、GC—MS分离测定,优化了加速溶剂萃取和凝胶色谱净化的条件。结果表明,多环芳烃的平均回收率为82.1%~106.4%,相对标准偏差为1.2%~4.8%。方法具有灵敏度高、准确度好、快速、消耗溶剂少的优点,适用于土壤等固体样品中多环芳烃的分离、净化和分析。     

A two-column method for long-term monitoring of non-methane hydrocarbons (NMHCs) and oxygenated volatile organic compounds (o-VOCs)

A method has been developed for concurrent analysis of C2-C7 hydrocarbons and C2-C5 oxygenated volatile organic compounds (o-VOCs) including alcohols, aldehydes, ketones and ethers. A multi-bed, Peltier-cooled adsorbent trap, consisting of Carboxen 1000 and Carbopack B, was used to acquire one sample per hour. Upon injection the sample was split in an approximately 50:50 ratio between a 50 m aluminium oxide (Al2O3) porous layer open tubular (PLOT) column and a 10 m LOWOX column. Eluents from each column were then analysed using flame ionisation detection (FID). Regular calibration of the system was performed using a standard cylinder mixture at the parts per billion by volume (ppbV) level for non-methane hydrocarbons (NMHCs) and a permeation tube method for the oxygenated species. The system is fully automated with NMHC detection limits between 1 and 10 parts per trillion by volume (pptV) and o-VOC detection limits between 10 and 40 pptV.     

Peak exposures in aluminium potrooms: instrument development and field calibration

Aluminium smelter potrooms are unique in that workplace exposures to hydrogen fluoride (HF), sulfur dioxide (SO2), and particulate matter occur simultaneously for some tasks. The peak exposures to these contaminants are of increasing interest in discovering the etiology of respiratory health effects. While a variety of direct-reading instruments are available for sulfur dioxide and particulate matter, only a few exist for hydrogen fluoride. The sensors in these HF instruments have a cross-sensitivity to sulfur dioxide making it difficult to monitor HF in an environment that also contains SO2. To overcome this problem, we assessed the simultaneous use of two electrochemical instruments: one with a SO2 sensor that does not respond to HF and the second with a hydrogen fluoride sensor that responds to both HF and SO2 in a 1 : 1 ratio, termed 'total acid gas'. The difference in the response between the two instruments should indicate the HF concentration: [HF + SO2] minus SO2 equals HF. The performance characteristics of this sampling train were evaluated in the laboratory through the generation of both HF and SO2 with permeation tubes. The response and recovery times for the SO2 only instrument were acceptable (6 and 15 s, respectively), but the "total acid gas" instrument exhibited both slow response and slow recovery approaching three and six min. The association between the traditional integrated filter sampling method and the direct-reading instrument for SO2 is 0.80 (Spearman's rho). The use of the digital filter strengthens the association between the HF direct-reading instrument and the integrated samples from 0.41 to 0.68.     

Determination of alkylamine permeation through protective gloves using aliphatic amine pads

A quantitative study of alkylamine permeation through a glove material using Permea-Tec aliphatic amine pads, used for the detection of chemical breakthrough of protective clothing, was performed for triethylamine following a microwave-extraction process and gas chromatographic analysis. Triethylamine exhibited > 99% adsorption on the pads at a spiking level of 729 ng (1.0 ml). Triethylamine showed recoveries from 63 to 90% (RSD < or = 5%) over the range 0.2-1.0 ml (146-729 ng) applied to pads. The ASTM F739 standard and direct permeability testing procedures were used to determine breakthrough times for five protective glove materials using triethylamine as a challenge chemical. Breakthrough times for six protective gloves were determined ranging from 40 s to > 4 h. The quantitative concentration of triethylamine on the pads following permeation through the gloves was also determined, ranging from 101 to 103 ng cm-2 (382-386 ng per pad).     

Rapid analysis of tile industry gaseous emissions by ion mobility spectrometry and comparison with solid phase micro-extraction/gas chromatography/mass spectrometry

The present paper reports on a rapid method for the analysis of gaseous emissions from ceramic industry, based on ion mobility spectrometry (IMS) as a means for on-site monitoring of volatile organic compounds (VOCs) produced during tile baking. IMS was calibrated with a set of reference compounds (i.e. ethyl acetate, ethanol, ethylene glycol, diethylene glycol, acetaldehyde, formaldehyde, 2-methyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 1,3-dioxolane, 1,4-dioxane, benzene, toluene, cyclohexane, acetone, acetic acid) via air-flow permeation. The technique was tested on a laboratory-scale kiln and tiles prepared with selected glycol- and resin-based additives. Finally, the analytical method was applied to emissions from two industries in the Modena (Italy) ceramic area. The results of all experimental phases were compared to those obtained by solid phase micro-extraction/gas chromatography/mass spectrometry (SPME/GC/MS). IMS showed potential as a real-time monitoring device for quality assessment in ceramic industry emissions. IMS spectra, SPME/GC/MS data, relationship between additives/baking conditions and produced VOCs and advantages and limitations of both techniques will be discussed.     

解决对氨基二甲基苯胺光度法测定硫化物中的几个问题

介绍对氨基二甲基苯胺光度法测定硫化物方法中如何降低空白值,提高硫化钠溶液的稳定度以及提高酸化吹气回收率的原理和方法.     

Determination of solvents permeating through chemical protective clothing with a microsensor array

The performance of a novel prototype instrument in determining solvents and solvent mixtures permeating through samples of chemical protective clothing (CPC) materials was evaluated. The instrument contains a mini-preconcentrator and an array of three polymer-coated surface-acoustic-wave (SAW) microsensors whose collective response patterns are used to discriminate among multiple permeants. Permeation tests were performed with a 2.54 cm diameter test cell in an open-loop configuration on samples of common glove materials challenged with four individual solvents, three binary mixtures, and two ternary mixtures. Breakthrough times, defined as the times required for the permeation rate to reach a value of 1 microg cm(-2) min(-1), determined by the instrument were within 3 min of those determined in parallel by manual sampling and gas chromatographic analysis. Permeating solvents were recognized (identified) from their response patterns in 59 out of 64 measurements (92%) and their vapor concentrations were quantified to an accuracy of +/- 31% (typically +/- 10%). These results demonstrate the potential for such instrumentation to provide semi-automated field or bench-top screening of CPC permeation resistance.     

危险废物焚烧处置项目竣工环境保护验收监测要点

对危险废物焚烧处置项目竣工环境保护验收监测中尚需明确的要点进行了剖析,并从入炉危废种类及比例、焚烧量的控制、助燃剂加入量、空气过剩系统的把握,以及安全管理检查要点等方面,提出相应的解决办法。     

顶空气相色谱分析原理与技术

系统讨论了静态顶空气相色谱的原理,包括多次相平衡法、改变相比法和标准加入定量法。测定了挥发性有机物在气液两相间的分配常数及其在水中的含量。提出了通过测定分配常数作为分析准确度的判据。研究了温度、相比、分配常数和无机盐对顶空分析灵敏度的影响。采用顶空色谱测定了河流底泥中的可酸挥发硫化物。