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1.
用乙醇提纯法提纯4-氨基安替比林比用活性炭脱色和氯仿萃取二法具有毒性小,操作简便,能满足测试要求.  相似文献   

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对4-氨基安替比林氯仿萃取比色法测定水中的挥发酵,如何更好地降低空白值作了介绍,阐述了对显色剂不同的提纯方法,并对各种方法作了合理的分析、评价。找出了一种既能降低测定空白值,又不影响方法的灵敏度,并保证分析结果精密度和准确度的方法。  相似文献   

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在挥发酚的监测中,通过对试剂4-氨基安替比林保存条件的对比实验证明,该试剂在棕色瓶中避光冷藏的条件下可存在半年,用于挥发酚测定其方法准确度及精密度均能达到要求。  相似文献   

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挥发酚的测定一般采用4一氨基安替比林光度法[1]。酚浓度小于0.1mg/L的采用4—氨基安替比林萃取光度法.大于0.1mg/L的采用4—氨基安替比林直接光度法。在例行监测中,我们事先并不知道水样中酚浓度的高低、仅根据以往的经验判断,这种判断时常有失误。由于直接法和萃取法所取馏出液的体积不同.加试剂的量也不同.当显色后发现浓度不在所用方法的范围之内时.只得重取水样.预蒸馏后用另一种方法显色测定,费时费力。为此.我们对直接法进行了改进,使其与萃取法所取馏出液体积相同,加试剂的量也相同.显色后若颜色较深.即用直接法…  相似文献   

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对4─氨基安替比林氯仿萃取比色法测定水中的挥发酚,如何更好地降低空白值作了介绍,阐述了对显色剂不同的提纯方法,并对各种方法作了合理的分析、评价.找出了一种既能降低测定空白值,又不影响方法的灵敏度,并保证分析结果精密度和准确度的方法.  相似文献   

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用4—氨基安替比林比色法测定土壤中挥发酚,经过对不同性质的土壤样品进行分析及质控实验,结果证明操作简便,准确度及精密度均符合质量保证要求。  相似文献   

10.
4-氨基安替比林比色法测定土壤中挥发酚含量探讨   总被引:3,自引:0,他引:3  
用4-氨基安替比林比色法测定土壤中挥发酚,经过不同性质的土壤样品进行分析及质控实验,结果证明操作其准确度及精密度均符合质量保证,满足环境监测要求.  相似文献   

11.
Tropospheric O3 has been implicated in the declining health of forest ecosystems in Europe and North America and has been shown to have negative consequences on human health. We have measured tropospheric ozone (O3) in the lower canopy through the use of passive monitors located in five woodlots along a 150 km urban–rural transect, originating in the large urban complex of Toronto, Canada. We also sampled foliage from 10 mature sugar maple trees in each woodlot and measured the concentration of a number of phenolic compounds and macronutrients. O3 concentrations were highest in the two rural woodlots, located approximately 150 km downwind of Toronto, when compared to the woodlots found within the Greater Toronto Area. Foliar concentrations of three flavonoids, avicularin, isoquercitrin, and quercitrin, were significantly greater and nitrogen concentrations significantly lower at these same rural woodlots, suggesting some physiological disruption is occurring in those sites where exposure to tropospheric O3 is greater. We suggest that foliar phenolics of sugar maple may be a biochemical indicator of tropospheric ozone exposure.  相似文献   

12.
废气净化装置排气中有机污染物的气相色谱/质谱分析   总被引:2,自引:0,他引:2  
利用活性炭对有机污染物具有较强的吸附和定量解吸的能力,对废气净化装置排气中的有机污染物进行吸附采样、溶剂解吸及气相色谱/质谱分析,可以克服气相色谱法依赖标样保留值定性的不足,扩大了定性范围,提高了准确度。  相似文献   

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总结了常用测定丙烯腈原料含量方法存在的不足,提出了以100减去水分和有机杂质的方法来确定丙烯腈含量。并对瓣老测定方法进行对比验证,结果表明,改进的方法操作简单,数据准确,可行。  相似文献   

14.
丙酮法和热乙醇法测定浮游植物叶绿素a的方法比对   总被引:4,自引:0,他引:4  
将丙酮法和热乙醇法用于测定浮游植物叶绿素a,分析水样中是否加入碳酸镁、水样体积、萃取时间、萃取剂、破碎方法、离心时间、水样存放时间和滤膜样品存放时间等8个因素对测定的影响,并确定最佳试验条件。结果表明:2种方法的测定值之间有较好的线性关系,相比丙酮法,热乙醇法更具优势。  相似文献   

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针对南京市典型道路的交通噪声控制措施,分别选取低噪声路面、声屏障、隔声窗3种噪声控制措施进行监测,监测显示低噪声路面对整体声级降噪有限,声屏障对于1kHz倍频带以上的中高频隔声相对较好,真空玻璃隔声窗能对低频噪声有显著改善。  相似文献   

16.
Personal exposure to air pollutants can be substantially higher in close proximity to an active source due to non-instantaneous mixing of emissions. The research presented in this paper quantifies this proximity effect for a non-buoyant source in 2 naturally ventilated homes in Northern California (CA), assessing its spatial and temporal variation and the influence of factors such as ventilation rate on its magnitude. To quantify how proximity to residential sources of indoor air pollutants affects human exposure, we performed 16 separate monitoring experiments in the living rooms of two detached single-family homes. CO (as a tracer gas) was released from a point source in the center of the room at a controlled emission rate for 5-12 h per experiment, while an array of 30-37 real-time monitors simultaneously measured CO concentrations with 15 s time resolution at radial distances ranging from 0.25-5 m under a range of ventilation conditions. Concentrations measured in close proximity (within 1 m) to the source were highly variable, with 5 min averages that typically varied by >100-fold. This variability was due to short-duration (<1 min) pollutant concentration peaks ("microplumes") that were frequently recorded in close proximity to the source. We decomposed the random microplume component from the total concentrations by subtracting predicted concentrations that assumed uniform, instantaneous mixing within the room and found that these microplumes can be modeled using a 3-parameter lognormal distribution. Average concentrations measured within 0.25 m of the source were 6-20 times as high as the predicted well-mixed concentrations.  相似文献   

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通过对空气湿度与总悬浮颗粒物之间关系的分析,得出平衡修正系数,提高了总悬浮颗粒物测定结果的准确性和时效性。  相似文献   

18.
A gas chromatograph with a flame photometric detector is set up for the direct analysis of COS, H2S, CS2, SO2, CH3SH, C2H5SH in ambient air.Logarithmic transformation is used to counterbalance the non-linear nature of the detector response for the individual sulphur gases. A quality assurance procedure is described to compensate any variation of response during field measurement. The use of Tedlar bags for sampling COS, CS2, CH3SH, C2H5SH is acceptable despite the general conception that sulphur gases are unstable in Tedlar bags.  相似文献   

19.
建立了适用于氨氮在线监测的干法蒸馏-电导法和湿法蒸馏-电导法。该方法是通入一定流量的气量于含氨试样中,全沸腾加热,蒸发出的氨和水蒸气一起经冷凝器后,进入酸吸收液中。酸吸收液的电导率随氨氮蒸馏液的吸收发生变化,其变化的值和样品中氨氮的浓度呈一定的比例关系。研制出的氨氮在线监测仪结构简单,运行稳定可靠,测量结果准确。  相似文献   

20.
巴歇尔槽测量雨水径流流量方法及其改进研究   总被引:1,自引:0,他引:1  
流量是研究城市非点源污染负荷和雨水径流污染物迁移转化规律的一项基本参数。针对明渠雨水径流流量测量问题,设计了改进的巴歇尔槽模型,通过水力特性试验率定该模型的水力参数,拟合出自由出流条件下水深-流量公式及上游水位与模型水头损失之间的关系,结合1∶2长度比尺缩小模型对改进槽型使用弗劳德模型律进行验证。结果表明,所建立的改进巴歇尔槽模型其拟合曲线R20.990,相对误差的绝对值5%,精确度较好,改进之后的槽型用于雨水明渠流量测量十分有效。  相似文献   

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