共查询到19条相似文献,搜索用时 78 毫秒
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气相色谱法测定空气中低分子量醛酮的方法研究 总被引:1,自引:0,他引:1
用2,4-二硝基苯肼为吸收液将空气和工业废气中的醛酮化合物定量吸收,以FID为检测嚣,2%OV-1玻璃柱为色谱柱,使得甲醛、乙醛等衍生物完全分离,并做了采样吸收效率实验,标准萃取液的稳定性实验. 相似文献
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无动力监测技术是一种成本低、效益高、灵敏而准确的空气气态污染物平均浓度监测采样方法,其连续时间覆盖可从几个小时到一个月.以月为采样周期时检测范围SO2为0.1~200μg/m3,NO2为0.1~400μg/m3,高灵敏度的检测下限可以满足低浓度背景区域内空气气态污染物的检出.其主要优点是采样器体积小、重量轻、无噪音、可重复利用、不用电、不需要技术人员、费用极低.采样器能在采样前后的常温条件下稳定几个月,因此能用于边远地区的环境监测.在检查模型计算和验证研究、健康影响评估、交通规划和绘制不同空气污染物在城市区域的高空间分辨率浓度分布图时,无动力采样器是最有价值的污染物高空间分辨率测定方法.文章所报道的是无动力采样技术的实际运用研究,是中瑞国际合作某项目的一部分,由瑞典环境科学研究院(IVL)与云南省环境监测中心站(YEMCS)共同完成. 相似文献
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本法用活性炭采样管富集空气中丙烯腈,用二硫化碳为溶剂,以GDX-502色谱柱,进行了采样、贮存和最佳条件试验。本方法的平均回收率为102%,相对标准偏差为4.4%,最低检测浓度0.28mg/m~3(按采样体积10升计)。 相似文献
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空气中多氯联苯的定量研究 总被引:2,自引:0,他引:2
使用大流量采样器,分别以石英纤维滤膜(QFF)和聚氨基甲酸乙酯泡沫(PUF)对空气中颗粒相和气相PCBs进行采集。以GC/MS为检测手段,采用选择性离子检测技术(SIM)对PCBs进行定性,内标法结合响应因子法进行PCBs的定量。PCBs的仪器检测限为4.40~93.60pg,回收率为68.57%~121.28%。气相和颗粒相PCBs的方法检测限分别为2.36~381.75fg/m3和2.78~348.81fg/m3。吸附和穿透试验结果表明,在采样流速为0.23m3/min、采样时间为24h的条件下,吸附和穿透情况对空气中PCBs的定量不会产生显著影响。 相似文献
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针对博物馆微环境中的碱性污染气体-氨气,采用自行研制的被动采样器,建立了一套适合博物馆馆藏文物保存环境中氨气含量分析的被动采样-离子色谱检测方法,应用于博物馆的实地采样分析,通过与主动法采样对照,获得了被动采样器在博物馆微环境中氨的吸收系数,从而获得采样点空气中氨气的浓度,为博物馆文物保存环境监测提供了可行方法。 相似文献
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目前国内外现行的空气中酚类化合物测定方法主要采用色谱法和4-氨基安替比林分光光度法.在色谱法测定中已有不少研究者采用了固体吸附剂的采样方法.在4-氨基安替比林分光光度法中还未见有采用固体吸附剂采样的测定方法的报导.本文采用层析硅胶做空气中酚类化合物的固体吸附剂,以碳酸钠水溶液作为 相似文献
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The use of underwater gaseous sensors has increased rapidly in the last 10 years. The majority of such sensors employ a thin membrane through which the gas diffuses. These sensors are potentiometric gas-sensing probes and essentially they are ion-selective electrodes. The deployment time of these membranes is curtailed by the formation of biofouling on the membrane leading to erroneous results. The physical properties of a variety of commonly used membranes were investigated using SEM and AFM. This showed that there were differences in topography between the PTFE membranes, such as pore sizes and surface roughness, which may be attributed to the manner in which they are manufactured. The pore size of the PTFE membranes varied greatly, ranging from circular pores with a diameter of 500 nm to elongated pores measuring 1 x 22 microm. The contact angle of each membrane showed that they were all hydrophobic. The amount of fouling on each was also observed and its affect on oxygen diffusion was monitored. Fouling slowed down the response of the instrument and caused reduced diffusion through the membranes. The amount of fouling varied between the membranes with the YSI membrane fouling least. Some of the membranes tested did foul less than others and there could be lifetime advantages of choosing a membrane with a smoother surface and a small pore size. 相似文献
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Evaluation of a novel hollow fiber membrane technique for collection of 1,1-dimethylhydrazine in air
Elnaz Taheri Abdulrahman Bahrami Farshid Ghorbani Shahna Maryam Farhadian 《Environmental monitoring and assessment》2018,190(8):479
The purpose of this study was to develop a novel one-step method for the time-weighted average determination of 1,1-dimethylhydrazine (UDMH) in the air followed by spectrophotometric detection. For this reason, 0.1% hydrochloric acid as the absorbent was used in hollow fiber (HF) membrane for sampling of UDMH from an atmospheric standard chamber. Response surface methodology (RSM) with central composite design (CCD) was used to optimize the sampling parameters, such as flow rate and sampling time. Moreover, several analytical parameters including breakthrough (BT) volume, storage time, and carryover effect of the proposed HF were investigated. The results showed that optimal sampling rate was 9.90 mL/min. In order to validate the proposed method, it was compared with the National Institute for Occupational Safety and Health (NIOSH) 3515 method, which showed good compatibility between the two methods. Intra- and inter-day repeatability values of the HF method were in the range 0.082–0.1 and 0.091–0.12, respectively, and the limits of detection (LODs) and limits of quantitation (LOQs) were 0.002 and 0.006 ng/mL, respectively. The storage time of the proposed HF was 7 days at 2 °C. These results demonstrated that the one-step HF membrane offered a high sensitivity for sampling of UDMH in air. 相似文献
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分析了隧道沥青摊铺过程环境空气中的TSP及多环芳烃质量浓度。TSP用膜法,中流量采样器采样15 min,重量法分析;超声波萃取,高效液相色法分析多环芳烃。结果表明,摊铺机周围空气中TSP超过8 mg/m3,道路空气中TSP超过3 mg/m3;环境空气中苊烯等12种多环芳烃均有检出,苊烯和艹屈质量浓度较高,苯并[a]芘和二苯并[a,h]蒽质量浓度较低。苯并[a]蒽、苯并[a]芘和二苯并[a,h]蒽超标,对人体健康危害较大。建议加强相关行业PAHs的排放水平及其健康风险研究,制定相关限值标准和沥青摊铺过程环境空气的沥青烟监测方法标准。 相似文献
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Lizhong Zhang Xuemei Guo Somenath Mitra 《Environmental monitoring and assessment》1997,44(1-3):529-540
On-line membrane extraction microtrap (OLMEM) gas chromatography was used for continuous monitoring of volatile organic compounds (VOCs) in water. The aqueous sample flowed through tubular membrane and the VOCs selectively permeated through it. The permeated VOCs were stripped by a carrier gas and transported to a microtrap. The microtrap retained and concentrated the analytes before injecting into a GC. In this study, the performance of a composite membrane was compared with that of a conventional silicone membrane. The advantages of using the composite membrane were higher extraction efficiency and shorter response time. Extraction efficiencies as high as 95% were obtained for compounds such as toluene and trichloroethane. 相似文献
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Schneider T 《Journal of environmental monitoring : JEM》1999,1(5):427-434
This paper presents key elements on which to base the design of a strategy for a particular indoor environment measurement task. Starting from a general strategy for responding to occupant complaints and conducting epidemiological and intervention studies the paper concentrates on selected key elements, with focus on air contaminants. Strategies for grouping of occupants with the purpose of exposure assessment should aim at optimising exposure contrast between groups, and grouping according to buildings may not be the proper choice. Occupant exposure can be measured by personal sampling or constructed from measured concentrations in microenvironments and activity patterns. The cause of temporal and spatial variability is discussed and guidance is given on the number of samples needed to detect a given change in true concentration level. The sick building syndrome (SBS) is defined as those situations where a high proportion of building occupants are complaining about mucous membrane or skin irritation, general symptoms. When investigating SBS, questionnaires should be used to collect structured information from occupants on perception of environmental conditions, psychosocial factors and symptoms. There is as yet no consensus on choice of length of reference period for reporting symptoms and for estimating exposure. Finally, methods for identifying and quantification of sources of air contaminants are discussed, including lab-scale or full-scale simulation, on-site measurement of source emission, air monitoring, surface sampling, and modelling. 相似文献
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X射线荧光光谱分析空气滤膜颗粒物中多种元素 总被引:1,自引:0,他引:1
采用X射线荧光光谱分析空气滤膜采集悬浮颗粒物中的多种元素,样品不需要前处理,不使用试剂,测量1个样品中40余种元素约耗时1 h。重复测量10次NIST SRM 2783空气滤膜标准样品,多数元素的测量值与标准值基本一致,测量值的标准偏差较小;测量20个空气滤膜实际样品,并与ICP-MS法作比对,大多数元素两种方法测量结果的相对偏差较小,测量值基本一致。 相似文献
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当前,中国城市环境空气污染形势十分严峻,空气质量呈现出典型的区域性特征。研究对2006—2012年各地区环境空气质量数据和经济社会发展指标统计资料面板数据进行分析,结果表明:研究选取时段内多数空气质量指标与人均国内生产总值之间的关系并不符合典型的环境库兹涅茨曲线(倒U型曲线),无显著相关性,但NO2质量浓度与人均国内生产总值之间呈现出倒N型曲线,空气质量综合指数与人口密度之间也呈现出倒N型曲线。空气质量综合指数与国民经济中第二产业占比和第三产业占比之间没有显著的相关关系,但与第一产业占比呈显著的负相关关系。空气质量综合指数与主要污染物单位面积排放量呈显著的正相关关系,与单位面积能源消费总量、单位面积煤炭消费量均呈显著的正相关关系,表明以煤炭为主要能源类型的能源消费带来的污染物排放是影响空气质量的主要因素。空气质量综合指数与降水量呈显著的负相关关系,降水量等气象条件对空气质量有一定影响,在开展大气污染防治时,应综合考虑各地的自然因素特征,合理确定工作目标和防治对策。 相似文献
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Vikas Singh 《Environmental Modeling and Assessment》2016,21(5):591-601
Image classification techniques have been applied to detect higher pollution episodes in modelled air pollution data. These techniques are widely used in video processing to find patterns in videos. An attempt for the first time has been made to apply these techniques by considering air pollution as continuous video frames as the spatio-temporal changes in the pollution are linked to its previous state of the atmosphere. The applicability of these techniques has been tested over Northern Italy to detect ozone pollution episodes in year 2004 using model simulated concentrations. The methods tested in this paper are pixel, block-based, histogram, pertinent pixel and twin-comparison method. While these techniques have some kind of merits and demerits, a modified pertinent pixel comparison algorithm has been proposed to detect pollution episodes. The proposed method has been validated to detect PM10 episodes over Milan metropolitan area during 2 months in 2008 and is able to detect PM10 episodic events as well as non-events. This method provides a single binary index that can be applied by the air quality modellers and decision makers to determine the pollution episode over a given domain. 相似文献