火焰原子吸收光谱法测定空气中铬含量的不确定度评定

用火焰原子吸收光谱法测定空气中铬含量,评定了测定过程的不确定度,把不确定度分解为标准溶液及配制引入的不确定度、标准曲线拟合引入的不确定度和样品重复测定引入的不确定度等七个因素,系统分析并计算各不确定度分量和扩展不确定度.结果表明,其中采集样品引入的不确定度是主要影响因素,空气中铬含量为3.88 μg/m3时,扩展不确定度为0.12 μg/m3.     

内标校正气相色谱–质谱法测定空气PM2.5中邻苯二甲酸二(2-乙基己基)酯的不确定度评定

建立内标校正气相色谱–质谱法测定空气PM2.5中邻苯二甲酸二(2-乙基己基)酯(DEHP)的不确定度评定方法,分析影响测量结果不确定度的因素,为提高检测结果质量提供依据.依据JJF 1059.1—2012《测量不确定度评定与表示》,建立数学模型,分析不确定度来源,评定各不确定度分量,计算合成标准不确定度和扩展不确定度....     

环境空气监测气体分析仪在线校准装置研制

设计一种新型的膜渗透动态配气系统,将动态配气膜渗透技术、基体空气标准添加方法、大气采样技术相结合,研制环境空气监测气体分析仪在线校准装置.该装置实现了环境空气污染组分SO2、NO2、CO在线监测仪的连续、实时、基体添加校准,校准不确定度小于3％(k=2).设计的长寿命膜渗透动态配气系统制备的标准气体混合物,可以连续使用...     

分光光度法测定空气中甲醛不确定度评定

采用分光光度法测定空气中甲醛,对测定结果的不确定度进行评定。采用酚试剂分光光度法测定空气中甲醛,分析测定过程中的各项不确定度来源,包括样品采集、标准工作溶液配制、标准工作曲线拟合、测定仪器以及重复测定等引入的不确定度,计算合成不确定度,最后获得相对扩展不确定度。当空气中甲醛质量浓度为0.0244~0.2218 mg/m^3时,测定结果在95%置信区间时的相对扩展不确定度为0.1172(k=2)。不确定度主要来源于A类不确定度和系列标准工作溶液制备、标准工作曲线拟合、水中甲醛溶液标准物质的稀释引入的不确定度。     

顶空气相色谱法测定医用透明质酸钠凝胶中乙醇残留量的不确定度

按YY 0308-2004要求,采用顶空气相色谱法测定了医用透明质酸钠凝胶中的乙醇残留量,依据JJF l059-1999,CNAS-GL 06,对测量结果的不确定度来源进行了系统分析,并对各不确定度分量进行了评定和量化,计算了合成标准不确定度和扩展不确定度,测定结果为(344.10±37.51)μg/g,k=2。结果表明,影响测量结果的主要因素为标准曲线拟合引入的不确定度。     

废气中甲醇采样方法和分析方法的改进

正甲醇是最简单的饱和一元醇,也是重要的化学工业基础原料和清洁液体燃料,广泛应用于有机合成、医药、农药、涂料、染料、汽车和国防等工业中。甲醇毒性较大,误饮或长期接触都会引起中毒,因此国家相关标准对空气中[1]甲醇含量和污染源甲醇排放浓度[2]都作了相应规定。相应的甲醇监测方法有HJ/T 33-1999[3]和《空气和废气监测分析方法(第四版增补版)》[4]的气相色谱法和分光光度法。在实际监测过程中,根据     

顶空气相色谱法测定聚氯乙烯固体药用硬片中氯乙烯单体含量的测量不确定度评定

依据CNAS-GL06,对顶空气相色谱法测定聚氯乙烯固体药用硬片中氯乙烯单体含量的测量不确定度进行系统分析,找出影响测量结果不确定度的主要因素。对各不确定度分量进行了评定和量化,计算了合成标准不确定度和扩展不确定度,聚氯乙烯固体药用硬片中氯乙烯单体含量的测定结果表示为(4.17±0.18)×10-7,k=2。     

SO2气体对质子交换膜燃料电池阴极性能的影响

将5×10-8~3.2×10-6(空气中的体积含量)的SO2通入质子交换膜燃料电池(PEMFC)单电池阴极, 研究了SO2对PEMFC性能的影响. 实验得到的电压-时间(V-t)曲线和极化(V-I)曲线表明, 空气中SO2含量达到5×10-7时, 将对PEMFC的性能产生显著的和不可逆的影响, 且SO2浓度越大电池性能的下降幅度越大. 对SO2影响前后的电化学交流阻抗谱(EIS)的解析表明, 电池电荷传递阻抗(Rct)的变化可逆, 而阴极的表面状态发生了不完全可逆的变化. 循环伏安(CV)实验数据进一步证明, SO2毒化后阴极的活性电化学表面积(EAS)缩小.     

工业炉窑排放粉尘监测的测量不确定度评定

在理解JJg 1059-1999(测量不确定度评定与表示>的基础上,对按照国家标准GB/T 16157-1996(固定污染源排气中颗粒物测定与气态污染物采样方法>,监测工业炉窑排放粉尘的测量结果不确定度进行了评定.对影响测量结果的系统效应、随机效应产生的不确定度分量进行了分析和量化,当排放粉尘的浓度为18.3 mg/m3时,扩展不确定度为6.6 mg/m3(k=2).     

大气降水钠的测定中外界影响因素的去除

近年来,随着环境管理力度的加强,对酸雨的监测逐步重视,监测项目除传统的pH、电导率外,又增加了K 、Na 、Ca2 、Mg2 、SO42-、Cl-、NO3-、NH4 等多项离子。大气降水中钠测定,目前主要采用火焰原子吸收光谱法[1]。由于自然界中钠的含量十分丰富,空气、水、土壤及玻璃中都含有大量的钠,这些物质对大气降水中钠测定有十分严重的影响,使测定结果产生较大的正误差,甚至使测定无法进行。本文从以下4个方面对外界影响因素加以探讨。1采样过程1.1影响因素空气中的灰尘;降水采样器材质。1.2去除影响的办法(1)采样一般使用降水自助采样器或聚乙烯…     

空气中苯系物测定有关问题的探讨

对HJ 584–2010《环境空气苯系物的测定活性炭吸附/二硫化碳解吸–气相色谱法》和HJ 583–2010《环境空气苯系物的测定固体吸附/热脱附–气相色谱法》进行解析,结合监测工作实际情况,从采样、分析各个关键环节总结归纳了方法要点,提出了实际应用中的注意事项。为环保监测系统进行空气中苯系物测定方法的选择及正确应用提供借鉴。     

X-ray photoelectron spectrometric and x-ray fluorometric studies of sulphur compounds on the surface of copper plates exposed to the atmosphere

X-Ray photoelectron spectroscopy (XPS) and XRF as techniques for monitoring air pollution are compared. Sulphide and oxides of sulphur (SO(2), SO(3) and SO(2-)(4)) have been determined on copper plates exposed for different lengths of time to an atmosphere containing hydrogen sulphide. The total amount of sulphur increases with the time of exposure but the sulphide reaches a constant value after 59 days. An interpretation of the mechanism of oxidation of hydrogen sulphide is offered.     

空气净化吸附剂的制备及其吸附性能研究

随着现代工业的迅速发展，有毒废气严重危害人们的健康，治理废气污染已经成为环境保护的热点之一。本文介绍合成二个系列大孔共聚物GT和GTD，经功能基化，制得具有净化空气中的过量的CO2、SO2和NO2的吸附剂。     

离子色谱-伏安极谱法联用同时测量空气中阴阳离子及重金属含量

通过空气样品液化器中真空泵的作用,空气转化为液体,从而能持续提供样品流,以供离子色谱仪和伏安极谱仪检测。阐述了将空气样品液化器(PILS)与伏安极谱仪(VA)、离子色谱仪(IC)联机分析空气中气溶胶的方法,其中伏安极谱仪可以分析空气中的Zn、Cd、Pb、Cu等重金属含量,离子色谱仪可以分析空气中的Cl-、NO2-、NO3-、SO42-、Li+、Na+、NH4+、K+、Ca2+、Mg2+等阴、阳离子的含量。方法取得了很好的精密度与准确度。     

On-line collection/concentration and detection of sulfur dioxide in air by flow-injection spectrophotometry coupled with a chromatomembrane cell.

A simple and rapid procedure for SO2 determination in air was developed by using a flow injection analysis (FIA) system coupled with a 3-hole chromatomembrane cell (CMC). The CMC was applied for the on-line collection/concentration of SO2 from air into a solution of 2 g l(-1) triethanolamine (TEA) solution as an absorbing solution: SO2 was converted to SO3(2-) in the alkaline absorbing solution. The solution containing absorbed SO2 was introduced into the carrier stream of the FIA system. The amount of SO3(2-) in the absorbing solution was measured by spectrophotometry with a mixed reagent of pararosaniline and formaldehyde, and was converted to the concentration of SO2 in the air sample. A calibration graph prepared by using standard sodium sulfite aqueous solutions was adopted for the determination of SO3(2-) in the absorbing solution. The SO2 concentration in indoor air examined was found to be 22.7 +/- 0.2 ppbv using 20 ml of air sample with the air flow rate of 5 ml min(-1), where the relative standard deviation was 1.7%. The detection limit for aqueous solutions and air samples were 6.9 x 10(-8) M and 0.48 ppbv, respectively. The measuring time for one sample was about 10 min when a 20 ml air sample was used. The interferences from common anionic species, formaldehyde and acetaldehyde, were also examined.     

室内空气测量不确定度评定进展

介绍了测量不确定度的研究进展及《民用建筑工程室内环境污染控制规范》(GB 50325-2001)中规定的室内5种空气污染物氡、甲醛、氨、苯、TVOC检测不确定度的评定概况,室内空气污染物测量不确定度的评定还处于较低水平,有待系统研究。     

Molecular behavior of the aptamer HJ24 self-assembled on highly oriented pyrolytic graphite (HOPG)

Nucleic acid sensing analysis has been widely applied to the fields of food quality control, environmental monitoring, and medical diagnosis. A key step in developing effective DNA-based electrochemical biosensors is to obtain a biorecognition layer on the biosensor, which can be influenced by many factors. Hence, we constructed a series of HJ24 layers on highly oriented pyrolytic graphite to investigate the relation between the configuration of the adsorbed probe HJ24 and the redox property using atomic force microscopy and voltammetry. We used HJ24 for its diagnostic value as it specifically recognizes the SH2 domain-containing phosphatase, a critical contributor in many important signaling pathways. The results demonstrated that increasing K ions induced G-quartet oxidation peak occurrence/increase([K+]?400 mmol/L), and also resulted in the formation of more compact single strand sheets([K+]?300 mmol/L). Moreover, transitions of molecule configurations and redox currents of G-quartets were observed at low concentration [K+]=12 mmol/L, which may indicate the appearance of new configurations under this condition. Besides, by analyzing atomic force microscopy(AFM) images, it was found that the different adsorbed configurations are correlated with the HJ24 concentration, the basal configuration, and the linker group on the HJ24 sequence. This information may be useful for understanding the adsorption process of HJ24 as well as for the further development of practical applications for HJ24 films on DNA electrochemical sensors, and may ultimately help improve the diagnosis and treatment of patients with SHP2-related diseases.     

Thermal dissociation of SO3 at 1000-1400 K

The thermal dissociation of SO3 has been studied for the first time in the 1000-1400 K range. The experiments were conducted in a laminar flow reactor at atmospheric pressure, with nitrogen as the bath gas. On the basis of the flow reactor data, a rate constant for SO3 + N2 --> SO2 + O + N2 (R1b) of 5.7 x 10(17) exp(-40000/T) cm3/(mol s) is derived for the temperature range 1273-1348 K. The estimated uncertainty is a factor of 2. The rate constant corresponds to a value of the reverse reaction of k1 approximately 1.8 x 10(15) cm6 mol(-2) s(-1). The reaction is in the fall-off region under the investigated conditions. The temperature and pressure dependence of SO2 + O (+N2) was estimated from the extrapolation of low temperature results for the reaction, together with an estimated broadening parameter and the high-pressure limit determined recently by Naidoo, Goumri, and Marshall (Proc. Combust. Inst. 2005, 30, 1219-1225). The theoretical rate constant is in good agreement with the experimental results. The improved accuracy in k(1) allows a reassessment of the rate constant for SO3 + O --> SO2 + O2 (R2) based on the data of Smith, Tseregounis, and Wang (Int. J. Chem. Kinet. 1982, 14, 679-697), who conducted experiments on a low-pressure CO/O2/Ar flame doped with SO2. At the location in the flame where the net SO3 formation rate is zero, k2 = k1[SO2][M]/[SO3]. A value of 6.9 x 10(10) cm3 mol(-1) s(-1) is obtained for k2 at 1269 K with an uncertainty a factor of 3. A recommended rate constant k2 = 7.8 x 10(11) exp(-3065/T) cm3 mol(-1) s(-1) is consistent with other flame results as well as the present flow reactor data.     

分光光度法测定室内空气中甲醛含量不确定度评定

对室内空气中甲醛含量分析测试过程的误差进行了辨别.在此基础上评定了分析结果的不确定度.不确定度主要来源于样品采集、样品处理、标准溶液、标准曲线制作以及其它仪器的使用.依据不确定度评定的步骤,分析和计算得到了各分量不确定度和合成不确定度.