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对饮用水、地下水、天然水和高度净化过的废水出口的清洁水样 ,采用纳氏试剂光度法测定氨氮时 ,无论是采取直接比色法还是絮凝沉淀预处理水样中 ,存在的浊度往往会对纳氏试剂比色的测定结果产生影响。为此 ,建议做补偿校正 :在5 0 ml比色管中 ,水样定容后加 1 .0 ml酒石酸钾钠溶液 ,混匀。加 1 .5 ml1 5 %氢氧化钾溶液 ,测量吸光度 (此为校正吸光度 )。然后从水样经纳氏试剂比色测得吸光度中减去校正吸光度。浊度在氨氮测定中的干扰及其消除@俞是聃$三明市环境监测站!福建三明365000… 相似文献
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实验部分 一、原理及方法:汞蒸气对波长253.7nm的光有选择性吸收,在一定温度范围内,吸光度与汞蒸气浓度成正比。 水样经消化后,将各种形态的汞全部转化为二价汞离子,过量的氧化剂用盐酸羟胺还原,然后用氯化亚锡将汞离子还原为单质汞。在室温下,由载气将单质汞蒸气导入吸收管,在波长253.7nm处测定其吸光度,根据吸光度与浓度关系进行定量。用已知不同浓度的Hg离子标 相似文献
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一、实验方法 1.试剂 铂钴色度标准、铬钴色度标准:按常规方法配制。 2.分光光度法 (1)按常规方法,配制0—200度的标准系列,并用分光光度计以420 nm波长、5cm比色皿测定吸光度,绘制标准曲线。 (2)澄清水样可直接测定,由标准曲线查得色度。若水样色度过高,应用蒸馏水稀释。 相似文献
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在总氮测定中消解时间不够或高压锅压力不足 ,均会造成过硫酸钾分解不完全 ,从而导致空白吸光度偏高 ,标准曲线线性和结果重现性差。 ( 1 )样品消解 1 0、2 0、30、40 min,2 2 0 nm处的空白吸光度分别为 0 .378、0 .0 35、0 .0 1 5、0 .0 1 4,故样品至少需消解 30 min。 ( 2 )用家用高压锅消解样品 ,稍有漏气 ,消解 30 min,2 2 0 nm处的空白吸光度在0 .2 30~ 0 .874之间 ,空白吸光度高 (有时高于祥品吸光度 )且波动性大。不漏气情况下的空白吸光度在 0 .0 1 5左右 ,波动性小。因此消解时要注意观察高压锅是否漏气总氮测定中的一点体会@赵多… 相似文献
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磷钼蓝比色法合适工作波长及线性范围的探讨 总被引:1,自引:0,他引:1
采用抗坏血酸-钼锑抗混合液作为磷钼蓝比色法测定磷含量的显色剂,形成稳定的显色液后,应用756CRT型紫外可见分光光度计进行600~850nm范围内的波长扫描。结果表明,吸收峰在722.2nm附近,同时,对720nm波长下的吸光度值与不同磷浓度吸收峰下的吸光度值进行比较,两者无显著差异。并且考虑到对于普通型的分光光度计很难做到722.2nm这样精确的调节。所以,可把720nm作为合适的工作波长,且磷浓度在0~1.0mg/kg内呈线性范围。 相似文献
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研究了用1-(2,6-二氯-4-硝基苯)-3-(4-硝基苯)-三氮烯(DCNPNPT)分光光度法快速直接测定锌的方法。在表面活性剂TritonX-15的存在下,pH=9.5~10.5的Na2B4O7-NaOH介质中,DCNPNPT与锌( )可生成1∶3的橙黄色络合物。最大吸收波长为445nm,同时在535nm配合物有一最大负吸收,建立以535nm为参比波长,445nm为测定波长的双峰双波长法进行测定,表观摩尔吸光系数可达1.12×105L/(mol·cm)。用拟定的方法测定矿山废水中的锌,与原子吸收法测定的结果十分吻合,结果令人满意。 相似文献
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影响总氮准确定量的光谱检测因素 总被引:2,自引:2,他引:0
对现行的双波长紫外分光光度法在测定水体总氮中由光学检测本身所产生的影响因素进行了探讨,提出了一种基于三波长的光谱检测总氮量的方法。结果表明,由于仪器信号波动或光散射引起的光谱检测基线上移所造成的误差可以用在NO3-没有吸收的340 nm处的吸光度加以判断,从而用三波长的方法扣除由于光谱基线上移对220 nm和275 nm处吸光度检测的干扰。对2个水样进行同样的光谱检测,以不同的计算公式所得的数据比较可以看出,三波长法明显优于双波长法。三波长法检测重现性相对偏差小于0.2%,其总氮含量的结果要比双波长法高7%~16%。这也解决了人们对总氮含量测定结果总是偏低的困惑。 相似文献
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A suite of twelve assays has been used to 'fingerprint' dissolved organic matter (DOM). The assays were applied directly to filtered natural water samples. Temperature, pH and conductivity accounted for the environmental conditions on-site. Bulk carbon characteristics were assayed by measuring UV absorbance at 200 and 240 nm, colour in grade Hazen, DOC (dissolved organic carbon), fluorescence (excitation 370 nm, emission 450 nm) and the complexation of phenol itself. Measuring hydroxybenzenes ('monophenolics'), polyhydroxybenzenes ('polyphenolics') and total phenolics with the Gibbs, Prussian Blue and Folin-Ciocalteau assays, respectively, determined the phenolics pool. The methodology was tested on six freshwater sites in North Wales chosen to provide differences in vegetation, land-use and water chemistry and sampled once during each season. A novel approach for the presentation of the data has been developed that combines all range normalised assay results for each site and each season within one polar plot, hence the term 'fingerprint'. The data was also analysed using principal component factor analysis. Assays characterised as determining the chemical properties of DOM contributed to Factor 1 and explained 59% of the variation in the data. Assays apparently determined by the water matrix, contributed to Factor 2 and explained 20% of the variation within the data. The factor scores obtained for each site showed more variation for assays relating to the chemical properties of DOM than to the surrounding water matrix. The methodology was found to detect chemical changes within DOM for each site throughout the year and different responses for different sites. 相似文献
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Kumar KS Swaroop BL Suvardhan K Rekha D Jayaraj B Chiranjeevi P 《Environmental monitoring and assessment》2006,122(1-3):1-8
A novel reagent was introduced for the facile and sensitive spectrophotometric determination of syntheitic pyrethroids in their formulations (fenvalerate, cypermethrin and decamethrin), water and grain samples. These methods were based on the hydrolysis of synthetic pyrethroids under the alkaline conditions to form respective aldehyde groups. These groups were condensation with 3-methyl-2-benzothiazolinone hydrochloride (MBTH) to yield color derivatives having λmax at 520 nm for fenvalerate, 516 nm for cypermethrin and 512 nm for decamethrin. The proposed method could be successfully applied for the determination of synthetic pyrethroids in their formulations, water and grain samples. 相似文献
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本文利用曲线补偿,变时溶出示差技术提高了测定Cu、Pb、Zn、Cd的灵敏度、精密度和准确度,进一步改变了谱图的分辨率,避免了O2波的干扰 相似文献
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Duester L Prasse C Vogel JV Vink JP Schaumann GE 《Journal of environmental monitoring : JEM》2011,13(5):1204-1211
The pore water transport of antimony and titanium, applied as nanoparticles (NPs), was studied by spiking stable suspensions of two different nanomaterials on the surface of an undisturbed floodplain soil. For preparation of stable dispersions, two different strategies were followed. (i) Comparable to those used in industrial applications: titanium dioxide nanoparticles, with an average diameter of 99 nm, were prepared by high-energy ball milling in water, whereas for (ii) antimony trioxide (Sb(2)O(3); average diameter 121 nm) a dispersing agent (sodium salt of poly[(naphthaleneformaldehyde)sulfonate] (pNFS) in water) was used. The upper 17 cm of a floodplain soil (river Rhine, Germany) was sampled using the minimally invasive sediment or fauna incubation experiment (SOFIE? two compartment cell; 3 l volume each), which preserved the pore system of the soil. The cells were equipped with 450 and 100 nm filter probes at different depths providing a non-invasive sampling of the pore water. The pore water was sampled at different times (T = 0, 24, 48, 96 and 196 h) and analysed by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). Sb and Ti were transported via the pore water of the floodplain soil to a depth of 14 cm, corresponding to the maximum cell depth. The highest Sb concentration in the pore water was detected after 24 h at a depth of 5.5-8 cm. Although the spiked concentration was higher for Ti than for Sb, the total Ti concentration in the pore water of the spiked cell was lower. This indicates a stronger agglomeration of TiO(2) NPs or a more intensive interaction of Ti with the solid matrix and a faster transport of Sb towards deeper soil layers. The results show that metal(loid)s from metal oxide NPs are transported in the soil pore water and, hence, have the potential to act as the source of contamination of deeper soil layers after soil surface contamination. 相似文献
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Cruceru I Florescu A Badea IA Vladescu L 《Environmental monitoring and assessment》2012,184(10):6061-6070
The level of three alkylphenols (APs) 4-nonylphenol, 4-octylphenol and 4-tert-octylphenol was monitored in various water samples using a new developed and validated HPLC method. The HPLC method employed a column with a mixed-mode stationary phase (C18/SCX) using a mobile phase of water to methanol?=?15:85 (v/v) delivered at a flow rate of 1 mL/min at room temperature. Both diode array, DAD and fluorescence, FLD detectors were employed. The method is linear when APs concentration ranged from 0.025 to 0.5 μg/mL with a DAD detection at 279 nm and between 0.0008 and 0.1 μg/mL when the detection was made by FLD (excitation at 220 nm, emission at 315 nm). The limit of detection and limit of quantitation for alkylphenols were found to be 5 and 15 ng/mL, respectively (detection by DAD). The method was employed with good results for the determination of APs in the presence of polycyclic aromatic hydrocarbons in various water samples. 相似文献