臭氧二级传递标准量值传递技术

臭氧(O_3)二级传递标准对O_3三级传递标准进行量值传递,开展了对分析类型、发生类型等不同类型O_3三级传递标准的量值传递实验。分析类型O_3三级传递标准6组校准斜率的相对标准偏差Sm为0.19%、截距的标准偏差SI为0.25 nmol/mol;发生类型O_3三级传递标准6组校准的Sm为0.67%、SI为0.20 nmol/mol,均符合美国环保局O_3二级传递标准量值传递的评价指标:6组多点校准斜率的相对标准偏差Sm≤3.7%,截距的标准偏差SI≤1.5 nmol/mol。进一步对分析类型、发生类型O_3三级传递标准分别进行了6个月的量值传递时间稳定性考察,O_3三级传递标准新的斜率与最近6组斜率均值的比值为0.965~1.037,且新计算的斜率的相对标准偏差Sm为0.37%~1.87%,截距的标准偏差SI为0.20~0.52 nmol/mol,均符合美国环保局量值传递评价指标的要求,建议至少每6个月采用O_3二级传递标准开展一次量值传递。     

臭氧一级校准数据读取方式对校准的影响研究

臭氧标准参考光度计同时采用串口连接模式、模拟信号连接模式和仪器数据存储-手动输入模式3种数据读取方式对臭氧二级传递标准进行一级校准,比较不同数据读取方式对校准结果的影响。串口连接模式和仪器数据存储-手动输入模式所得到校准曲线的斜率和截距具有很好的一致性,相差较小。经修正转化截距后的模拟信号连接模式所得到的斜率和截距相对于其他2种数据读取方式有一定的差别,但也在校准指标以内。     

SO_2连续采样实验室分析法实验室质量保证措施探讨

一、校准曲线的绘制 《规范》要求,标准曲线应每月重新绘制,要求标定标准溶液后至少做二次,共做二天。校准曲线的斜率b在0.039±0.003吸光度范围内,截距a应小于0.050吸光度。其变动范围应小于0.008吸光度。实验表明(结果略——编者),显色温度范围为19℃～28.5℃,两人的校准曲线斜率b为0.040±0.002吸光度,截距a     

水和废水中挥发酚、氰化物标准曲线评价指标研究

通过组织我省14个实验室开展水和废水中2个常规监测项目标准曲线评价指标研究工作,经对标准曲线指标进行检验,给出了我省范围内2个项目的标准曲线评价指标为:挥发酚截距a≤±0.008,斜率b范围为0.0305~0.0470;氰化物截距a≤±0.008,斜率b范围为0.1205~0.167。     

光度法校准曲线斜率的运用

1校准曲线斜率稳定性在分析中的运用 :斜率的平均相对偏差 <5%为稳定曲线 ,如亚硝酸盐氮和六价铬分析项目 ,可用带标点检验 ,不需制作校准曲线 ;偏差在 5%～ 1 0 %之间为较稳定曲线 ,如氨氮等项目 ,也可采取带标点检验 ;>1 0 %时为不稳定曲线 ,如二氧化硫分析 ,均需同时制作校准曲线。 2判断标准溶液稳定性 :斜率值显著降低时 ,标准溶液需重新配制或标定。光度法校准曲线斜率的运用@杨树成$射阳县环境监测站!江苏射阳224300     

动态校准仪臭氧间接传递技术

对5台主流动态校准仪开展臭氧间接传递技术研究,对动态校准仪的准确性、可靠性、稳定性及臭氧传递的线性方程等性能参数进行了实验室考察。总体而言,发生型动态校准仪和分析型动态校准仪均可用于臭氧传递工作中。分析型动态校准仪可直接进行臭氧传递,发生型动态校准仪在臭氧传递前必须进行预校准。建议至少每3个月对发生型动态校准仪进行1次臭氧传递,每6个月对分析型动态校准仪进行1次臭氧传递。     

紫外光度法臭氧自动监测仪及其标准传递方法

随着我国经济的快速增长和城市化进程的不断加速,以臭氧为主的光化学污染问题已成为大气环境保护领域关注的重点、热点问题。对臭氧进行自动监测是环境管理和科学研究的需要,文中介绍了臭氧自动监测仪和臭氧量值溯源体系,重点探讨了臭氧监测干扰因素及标准传递方法,并通过实验比较验证了带光度计的臭氧校准仪具有较好的输出稳定性。     

环境空气质量自动监测系统中动态校准仪臭氧浓度的复现性研究

通过对含有臭氧发生器的动态校准仪发生的臭氧浓度进行多角度跟踪审查,对其臭氧浓度的复现性进行了评估。总体上,动态校准仪臭氧发生器发生的臭氧浓度存在较大漂移,复现性较差,与臭氧组件的稳定性有很大关系。建议参照美国的臭氧传递分级标准,把动态校准仪作为Level 4级别的传递标准,使用专门用于校准的臭氧分析仪作为Level 3级别的传递标准,在子站现场对动态校准仪和监测用臭氧分析仪进行标准传递,并适当增加传递频次。     

校准曲线截距误差和检验方法

对环境监测样品的分析大部分采用校准曲线定量法,校准曲线拟合方程的质量对监测结果的可靠性影响很大。把测量信号值(ｙ)对标准物质含量(ｘ),用最小二乘法拟合校准曲线方程有两种方法,一种是直接拟合,一种是扣除空白信号值后再拟合,两种方法截距(ａ)的含义不同,这里论述的截距是指后者。1　截距误差产生的原因分析方法的依据是测量信号值与样品待测物质含量成某种确定的直线关系,空白信号估计值应是空白实际测定值。理论上校准曲线的截距应是0。非零截距是由截距误差产生的,其中包括随机误差、系统误差和过失误差。11　截距的随机误差以分光…     

二乙基二硫代氨基甲酸银光度法测定砷的改进

经过几年试验 ,发现采用ＧＢ 7485 - 87二乙基二硫代氨基甲酸银光度法测定水和废水中砷 ,砷校准曲线的斜率和相关系数存在一定程度的不稳定现象。在做砷校准曲线时 ,有时存在个别点偏高或偏低 ,导致截距不符合要求 ,相关系数不好 ,特别是夏天 ,最高浓度点的吸光值经常偏低。在1 994年— 2 0 0 1年所制作的 68条校准曲线中 ,斜率范围为 0 .0 2 93～ 0 .0 335 ,相关系数符合要求的校准曲线可用率占 88.2 %。究其原因 ,主要是未满足测定方法中规定的“于砷化氢发生瓶中迅速加入4ｇ无砷锌粒 ,并立即将导气管与发生瓶连接 (保证连接处不漏气 )”…     

大气自动监测校准中气体流量对仪器示值误差的影响及控制

研究了大气自动监测系统中标准气、校准气以及零空气的流量大小引起仪器示值误差及时校准曲线质量的影响,提出了重点控制标气流量是减小仪器示值误差的关键,从而解决了低浓度校准点仪器示值偏低、误差大及校准曲线截距大的技术难点,提高了大气自动监测中多点校准质量和监测结果的准确性.     

化学分析方法校准曲线有关问题的探讨

校准曲线的线性范围为测定下限与测定上限之间的浓度范围,测定上限应尽可能扩大,但要保证校准曲线呈线性,同时,最高点分析后不会对分析系统造成污染物残留。通常应根据分析方法原理、仪器的特点和样品基质情况来确定校准方式。对于线性校准曲线,除了相关系数外,还要根据不同情况,对校准曲线进行检验。校准曲线的合格判定,除考虑相关系数外,还需要用校准曲线重新计算校准点,对于线性校准,所有校准点计算结果拟合值与实际值的相对误差应在±30%以内,对于非线性二阶校准曲线,应进行最大值与最小值检验。     

荧光法生物气溶胶监测仪标准物质研制及校准方法研究

生物气溶胶监测仪是利用激光或紫外光诱导生物粒子发射荧光,从而实现对空气中的生物气溶胶进行监测的仪器。目前,国内尚无生物气溶胶监测仪校准用标准物质和评价方法。以聚苯乙烯微球为核,通过Friedel-Crafts酰基化反应,研制出能够自身受激发产生荧光的聚苯乙烯(PS-PB)微球。PS-PB微球粒径分布的相对标准偏差为1.3%,严格单分散。通过雾化法发尘,将PS-PB微球应用于生物气溶胶监测仪的校准,计数误差在±10%以内。用校准后的仪器检测白色念珠菌(Candida albicans)发生的生物气溶胶和商品化的荧光微球发生的气溶胶,计数误差均与PS-PB微球计数误差接近。研究结果表明,PS-PB微球可作为标准物质用于生物气溶胶监测仪器的校准,基于雾化发尘的静态箱法校准装置可用于生物气溶胶监测仪的评价。     

化学发光法臭氧分析仪的研制与性能测试

基于化学发光臭氧(O₃)检测方法，将氮氧化物分析仪(Thermo Model 42i-TL)改装为O₃分析仪，测试其性能，并与紫外光度法O₃分析仪(Thermo Model 49i)同时应用于外场观测，开展比对测试试验。结果显示：该改装仪器的测量性能优于Thermo Model 49i,其零点噪声为0.10×10^-9(体积分数，下同),最低检出限为0.20×10^-9,量程噪声为0.42×10^-9,示值误差为0.1%满量程(F.S.)。在比对试验过程中，化学发光法O₃分析仪运行稳定，测量结果与商品化的Thermo Model 49i所测定的O₃浓度数值的变化趋势高度一致(R²=0.998)。化学发光法O₃分析仪相较于Thermo Model 49i具有更低的噪声，其日间(09:00—17:00)O₃浓度示值显著低于Thermo Model 49i,且...     

超低沸点挥发性有机物测定中的要点分析

采用大气浓缩仪-气相色谱法测定超低沸点挥发性有机物乙烷、乙烯、丙烷、丙烯、乙炔,选用PLOT-Q柱分析,控制真空罐内相对湿度约50%,通过优化测定条件使方法线性良好,5种低沸点化合物的检出限为0.08 nmol/mol～0.2 nmol/mol,样品保存时间不超过10 d。用该方法测定某地区环境空气中VOCs,结果检出率均为100%。     

Equivalency of a personal dust monitor to the current United States coal mine respirable dust sampler

The United States National Institute for Occupational Safety and Health, through an informal partnership with industry, labor, and the United States Mine Safety and Health Administration, has developed and tested a new instrument known as the Personal Dust Monitor (PDM). The new dust monitor is an integral part of the cap lamp that coal miners normally carry to work and provides continuous information about the concentration of respirable coal mine dust within the breathing zone of that individual. Previous laboratory testing demonstrated that there is a 95% confidence that greater than 95% of individual PDM measurements fall within +/-25% of reference measurements. The work presented in this paper focuses on the relationship between the PDM and respirable dust concentrations currently measured by a coal mine dust personal sampler unit utilizing a 10 mm Dorr-Oliver nylon cyclone. The United Kingdom Mining Research Establishment instrument, used as the basis for coal mine respirable dust standards, had been designed specifically to match the United Kingdom British Medical Research Council (BMRC) criterion. The personal sampler is used with a 1.38 multiplier to convert readings to the BMRC criterion. A stratified random sampling design incorporating a proportionate allocation strategy was used to select a sample of mechanized mining units representative of all US underground coal mines. A sample of 180 mechanized mining units was chosen, representing approximately 20% of the mechanized mining units in production at the time the sample was selected. A total of 129 valid PDM/personal sampler dust sample sets were obtained. A weighted linear regression analysis of this data base shows that, in comparison with the personal sampler, the PDM requires a mass equivalency conversion multiplier of 1.05 [95% C.I.=(1.03, 1.08)] when the small intercept term is removed from the analysis. Removal of the intercept term results in a personal sampler-equivalent concentration increase of 2.9% at a PDM measurement of 2.0 mg m(-3).     

The Impact of Scrubber Sludge on Ground Water Quality at an Abandoned Mine Site

A sulfate-rich flue gas desulfurization scrubber sludge was used as a substitute backfill material in reclamation of an abandoned coal strip mine. The site was surrounded by monitor wells and the material was characterized for leaching behavior using open column experiments. A drain was placed directly beneath the 45 000 ton fill to enable sampling before dilution or attenuation. The column studies indicated that the scrubber sludge would adsorb manganese, iron, aluminium, cobalt, nickel, thallium and zinc contaminants from the water. Changes in pH appear inadequate to explain the removal by precipitation. The groundwater cleaning phenomenon has been confirmed on a field scale by the drain samples. Boron and molybdenum leach from the fly ash was used to fix the scrubber sludge and serve as marker elements enabling calibration of the dispersivity in computer models of the groundwater system at the site. The leachate front appears to be diluted by a factor of 8 : 1 within the first 15 meters. Since boron and molybdenum release are associated only with the first flush, environmental impacts will be minimal. Columns appear to create a time compression effect on the duration of leaching phenomenon. The effect for this site appears to be at least 5 : 1. The columns were effective in predicting which elements would leach or adsorb in the field and in predicting the actual source concentrations. Other shake tests such as the TCLP and the ASTM shake test were found to be less effective at predicting which elements would leach and were not helpful in predicting field concentrations.     

紫外光度法测定海水石油类质控指标研究

采取问卷调查的形式对76家"近海网"成员单位海水石油类测定情况进行调查,根据调查问卷获得的数据信息,结合实验室数据,采用控制图法确定了紫外光度法测定海水石油类质控指标限值,包括萃取剂透光率、检出限、校准曲线斜率、平行样偏差等。     

Impact of elevated O3 on visible foliar symptom, growth and biomass of Cinnamomum camphora seedlings under different nitrogen loads

The effects of elevated ozone (O(3)) and enhanced nitrogen (N) on the growth and biomass of Cinnamomum camphora, a subtropical evergreen broad-leaved tree species, were investigated. The seedlings, supplied with N (NH(4)NO(3) solution) at 0, 30 and 60 kg ha(-1) year(-1) (simplified as N0, N30, N60, respectively), were exposed to ambient (AA) or elevated O(3) (AA + 60 nmol mol(-1) and AA + 120 nmol mol(-1), designated as AA + 60 and AA + 120, respectively) for the 2009 and 2010 growing seasons. Symptomatic leaf percentages were significantly increased with O(3) concentration. AA + 120 significantly decreased the mean leaf size and chlorophyll content of both 2009- and 2010-emerged leaves, inhibited the growth of stem height and basal diameter, and reduced biomass accumulation of all plant parts except for leaves. By comparison, only the chlorophyll content of 2009-emerged leaves and root dry weight were significantly reduced under AA + 60. Specific leaf area, total leaf area and foliar biomass were not affected even at a higher O(3) level. On the other hand, N loads, especially N60, exerted significantly positive effects on all variables except mean leaf size and shoot/root ratio. No significant interactions between O(3) and N were detected, suggesting that the N supply at ≤60 kg ha(-1) year(-1) did not significantly modify the response of C. camphora to O(3) in terms of seedling growth and biomass accumulation.