自动搅拌萃取-紫外分光光度法测定常州市城市饮用水水源地石油类

根据《水质石油类的测定紫外分光光度法(试行)》(HJ 970—2018)的要求,以正己烷为溶剂,采用自行设计的搅拌式液液萃取器处理样品,萃取相经硅酸镁吸附脱除极性物质后,用紫外分光光度法测定常州市城市饮用水水源地的石油类指标。结果表明:方法检出限为0.01 mg/L,线性范围为0~16.0 mg/L,相关系数为0.9998,4种不同浓度配制样品测定的相对误差为-15.0%~4.0%,相对标准偏差为2.2%~8.8%。各项技术指标均满足《HJ 970—2018》相关质量控制要求,相比手动萃取-红外分光光度法,自动搅拌萃取-紫外分光光度法能有效提高分析效率和降低职业危害。     

环己二胺四乙酸二钠溶液配制的改进

《空气和废气监测分析方法》对空气中二氧化硫测定可用甲醛缓冲液吸收－盐酸副玫瑰苯胺分光光度法。在几年使用中,发现配制００５０ｍｏｌ／Ｌ环己二胺四乙酸二钠溶液有些问题,今对其加以改进。该书中方法为称取１８２ｇ反式－１,２－环己二胺四乙酸（简称ＣＤＴＡ...     

显色酸度对钼锑抗分光光度法测定土壤中总磷的影响

采用碱熔-钼锑抗分光光度法测定土壤中总磷时,显色溶液的酸度影响磷钼络合物的形成和稳定,p H指示剂2,4-二硝基苯酚在环境温度低时配制困难、辨色不明显。分析了显色酸度对吸光值的影响,并对2,4-二硝基苯酚的配制方法进行了改进,方法操作简单,提高了分析结果的准确性。     

总氮测试中碱性过硫酸钾溶液的稳定性

采用GB 11894-1989<过硫酸钾氧化-紫外分光光度法>测定地表水中总氮时,方法规定碱性过硫酸钾溶液最长可贮存1周,为了节约时间和试剂,现对配制的碱性过硫酸钾溶液作稳定性试验,以了解碱性过硫酸钾溶液在常温下的最长保存时间.     

红外分光光度法测定水中石油类应注意的问题

从实验环境、空白值、标准油的配制、标准曲线的配制和仪器操作5个方面对水中石油类测定红外分光光度法应注意的问题进行了探讨．     

S02标准溶液保存期的探讨

GB/T 1526-94《空气和废气检测分析方法(3版)》中甲醛吸收-副玫瑰苯胺分光光度法规定,10.00mg/L SO_2标准溶液放在冰箱(5℃,下同)的保存期为3个月～6个月,否则需重新配制并标定。SO_2标准溶液的配制及标定步骤较繁琐,且SO_2标准溶液标定后需用甲醛溶液稀释,而甲醛是     

SO2标准溶液保存期的探讨

GB/T 1526-94<空气和废气检测分析方法(3版)>中甲醛吸收-副玫瑰苯胺分光光度法规定,10.00mg/L SO2标准溶液放在冰箱(5℃,下同)的保存期为3个月～6个月,否则需重新配制并标定.SO2标准溶液的配制及标定步骤较繁琐,且SO2标准溶液标定后需用甲醛溶液稀释,而甲醛是对环境有污染的有毒有机溶剂.     

紫外分光光度法测定水中总氮影响条件的实验研究

碱性过硫酸钾氧化-紫外分光光度法测定水中总氮时，实验的准确性受到很多条件的影响。本文分别从试剂的选择、试剂的配制、消解的温度与时间、实验用水、比色管的选用及清洁度等方面进行研究，从而保证实验的准确性与可靠性。     

河水示踪剂的分光光度法的研究

在天然河流中,使用现场示踪剂技术来确定水团流程时间及各类混合输送参数。我们选用罗丹明B和工业染料碱性玫瑰精做河水的示踪剂,使用分光光度法进行检测,检出下限为0.005mg/1。 一、罗丹明B的分光光度法 配制罗丹明B标液,利用日本岛津UV—250紫外分光光度计和国产722型分光光度计,进行了分光光度法的波长选择,本底干扰以及其他影响因素的实验。 (一)波长的选择:在700～190nm波长范围内扫描(图1),结果表明,罗丹明B在可见光部分最大吸收波长λ_(max)为555nm。     

测定污染源氯气甲基橙分光光度法的改进

甲基橙分光光度法测定氯气是氯的特殊反应。现就甲基橙分光光度法测定污染源氯气时出现的问题进行讨论,并提出改进方法。1　吸收液的配制根据《空气和废气监测分析方法》甲基橙分光光度法测定污染源氯气,用作采样吸收液的甲基橙贮备液需用8 46×10-4ｍｏｌ/Ｌ溴酸钾标准溶液标定。在标定过程中,发现终点很难控制,不同的操作者滴定结果相差很大,即使同一操作者标定的重现性也不好。究其原因,该方法要求滴定将近终点时,每加入1滴溴酸钾标准溶液必须振摇5ｍｉｎ,但在操作中,振摇的时间不好掌握,并且每个人振摇的频率和强度也不太一样,加之…     

黄河水中氨基酸对Cu(Ⅱ)与沉积物相互作用等温线的影响

研究了黄河水中 Cu2 +与沉积物相互作用的等温线以及酪氨酸和谷氨酸对等温线的影响。得到的等温线具有一个“拐点”两个“平台”,是一种台阶型的二级交换等温线。用分级离子交换等温式求出了平衡常数 K1 和 K2 。氨基酸对微量金属与沉积物的相互作用有明显的影响 ,影响的程度取决于它们的浓度和等电点。实验证明 :低浓度的氨基酸促进Cu2 +与沉积物的交换吸附。当两种氨基酸的浓度相同时 ,促进作用的程度与氨基酸的等电点有关 ,酪氨酸的促进作用比谷氨酸大。     

Measurement of total antimony and antimony species in mine contaminated soils by ICPMS and HPLC-ICPMS

This paper describes the measurement of total antimony and antimony species in "real world" mine contaminated sediments using ICPMS and HPLC-ICPMS. Low and high temperature microwave extraction procedures (90 degrees C and 150 degrees C, respectively) using a range of nitric-hydrochloric acid combinations were examined as to their efficacy to extract antimony from six mine contaminated soils and a certified reference material. The use of the higher temperature with nitric-hydrochloric acid (1:2 (v/v)) was suitable to release antimony from sediments and the certified reference material, NIST 2710 Montana soil. Antimony concentrations obtained using this acid mixture were similar to those obtained using a more aggressive extraction with nitric, hydrochloric, perchloric and hydrofluoric acid mixture. A 25 mM citric acid solution at 90 degrees C for 15 min extracted 47-78% of antimony from soils. A Hamilton PRP X-100 anion exchange column with 20 mM EDTA mobile phase, pH 4.5, flow rate 1.5 mL min(-1) and column temperature of 50 degrees C was used to separate antimony species. Column recoveries ranged from 78-104%. The predominant form of antimony was Sb(5+). Little conversion of Sb(5+) occurred (<5%) during extraction, however, significant conversion of Sb(3+) occurred (approximately 36%). The extraction of antimony species with citric acid should be useful in the determination of inorganic antimony available to plants, as plants commonly excrete carboxylic acids, including citric acid, into their rhizospheres to mobilise trace elements for nutritional purposes.     

Quantification of protein adducts of hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in human plasma

Hexahydrophthalic anhydride (HHPA) and methylhexahydrophthalic anhydride (MHHPA) are two highly allergenic compounds used in the chemical industry. A method was developed for quantification of protein adducts of HHPA and MHHPA in human plasma. The plasma was dialysed and the anhydrides were hydrolysed from the proteins at mild acidic conditions. The released hexahydrophthalic acid (HHP acid) and methylhexahydrophthalic acid (MHHP acid) were purified by reversed solid phase extraction followed by derivatisation with pentafluorobenzyl bromide. The derivatives were analysed using GC-MS in negative ion chemical ionisation mode with ammonia as moderating gas. As internal standards, deuterium labelled HHP and MHHP acids were used. The detection limits were 0.06 pmol mL(-1) plasma for HHP acid and 0.03 pmol mL(-1) plasma for MHHP acid. The between-day precisions for HHP acid were 18% at 0.3 pmol mL(-1) and 8% at 4 pmol mL(-1). For MHHP acid, the precisions were 13% at 0.3 pmol mL(-1) and 9% at 4 pmol mL(-1). There were strong correlations (r=0.94 for HHPA and 0.99 for MHHPA) between total plasma protein adduct concentrations and serum albumin adduct levels. Workers exposed to time-weighted average air levels of HHPA between < 1 and 340 microg m(-3) and between 2 and 160 microg m(-3) for MHHPA had plasma adduct levels between the detection limits of the methods and 8.40 and 19.0 pmol mL(-1), respectively.     

土壤中总氰化物分析方法的研究

通过对底泥、土壤中氰化物预处理方法的选择,证明在硫酸介质中蒸馏,用氢氧化钠为吸收液,异烟酸吡唑啉酮光度法测定土壤中总氰化物的分析方法具有准确度高、精密度好等特点。     

Colorimetric determination of formaldehyde in air using a hanging drop of chromotropic acid

A simple and sensitive method to determine parts per billion (ppb) of atmospheric formaldehyde in situ, using chromotropic acid, is described. A colorimetric sensor, coupled to a droplet of 15.5 microL chromotropic acid, was constructed and used to sample and quantify formaldehyde. The sensor was set up with two optical fibers, a light emitting diode (LED) and two photodiodes. The reference and transmitted light were measured by a photodetection arrangement that converts the signals into units of absorbance. Air was sampled around the chromotropic acid droplet. A purple product was formed and measured after the sampling terminated (typically 7 min). The response is proportional to the sampling period, analyte concentration and sample flow rate. The detection limit is approximately 2 ppb and can be improved by using longer sampling times and/or a sampling flow rate higher than that used in this work, 200 mL min-1. The present technique affords a simple, inexpensive near real-time measurement with very little reagent consumption. The method is selective and highly sensitive. This sensor could be used either for outdoor or indoor atmospheres.     

石墨炉原子吸收光谱法测定环境空气中钴

采用超细玻璃纤维滤膜采集环境空气中钴,硝酸-过氧化氢-氢氟酸混合进行消解,采用硝酸镁和硝酸混合液作为基体改进剂,石墨炉原子吸收光谱法测定环境空气中钴。此方法对测定环境空气中钴的灵敏度、准确度都有很大的提高,方法的最低检出浓度为0.25μg/L,当采样体积为100 L,钴最低检出质量浓度为0.000 1 mg/m3。对实际样品进行分析,钴的加标回收率为91.0%~106.5%。     

Analysis of indoor gaseous formic and acetic acid, using radial diffusive samplers

A diffusive sampling method for the determination of gaseous acetic and formic acids, using a radial symmetry diffusive sampler, has been optimised for a 7-day exposure time in this study. Sampling rate determinations were performed on data obtained from a dynamic exposure chamber, simulating the indoor conditions of an empty, closed, room, at room temperature and minimal wind speed. Analysis has been performed by means of ion chromatography. The sampling rates for formic acid concentrations of 128 microg m(-3) and 1248 microg m(-3) were determined to be 91.2 +/- 3.9 ml min(-1) and 111.6 +/- 2.8 ml min(-1), respectively. The acetic acid sampling rate was independent of the concentration in the range 160 microg m(-3)-1564 microg m(-3), and amounted to 97.3 +/- 3.1 ml min(-1). Experimentally determined sampling rates showed deviations of 3% for acetic acid, and 3-21% for formic acid, in relation to theoretically derived values. The blank values were as low as 1.69 +/- 0.07 microg for formic acid and 1.21 +/- 0.14 microg for acetic acid, and detection limits lower than 0.5 microg m(-3) could be achieved, which is an improvement of 98-99% compared to previously validated diffusive sampling methods. This study describes the first step of an extended validation program in which the applicability of these types of samplers for the measurement of organic acids will be validated and optimised for the environmental conditions typical for museum showcases.     

Direct electrothermal atomic spectrometric determination of Ag in aqua regia extracts of soils, sediments, and sewage sludge with matrix modification

Silver is subject to significant interferences caused by high chloride concentrations in electrothermal atomic absorption spectrometry, thus its direct determination in aqua regia leaches from soils, sediments, and sludges is very difficult, especially when using instrumentation equipped with deuterium-lamp background correction (D₂). In this study, the interference of the aqua regia medium was successfully eliminated using Pd–citric acid chemical modifier. This chemical modifier was found to be the most advantageous in comparison with Pd mixture with ascorbic acid, tartaric acid, or citric acid–Li based on its ability to suppress the interference originating from different chloride matrix. Palladium increases the analyte stability; citric acid serves as a reducing reagent, and furthermore, it helps to remove the interfering chlorides by forming HCl, in the drying step of the electrothermal program. In the presence of the modifier, the pyrolysis temperature can be adjusted up to 1,000 °C with no loss of the analyte. The obtained limit of detection and characteristic mass were 5 ng g^?1 and 1.7 pg, respectively. The accuracy of the method was verified by means of six different reference samples and by comparing the results of the analysis of real samples with those obtained by inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometer. The proposed method was applied to the Ag determination in soils, sediments, and sewage sludge samples from the Pardubice region in Czech Republic.     

异烟酸-吡唑啉酮光度法测定氰化物的方法研究

研究了用次氯酸钠代替氯胺 T为活性氯试剂进行测定的方法 ,比较了这两种试剂对测定条件、结果的影响 ,且对蒸馏预处理方法进行了改进 ,并提出了在蒸馏预处理及异烟酸 -吡唑啉酮分光光度法测定过程中的注意事项     

Optimization of digestion parameters for analysing the total sulphur of mine tailings by inductively coupled plasma optical emission spectrometry

The oxidation of sulphidic mine tailings and consequent acid generation poses challenges for the environment. Accurate and precise analysis of sulphur content is necessary for impact assessment and management of mine tailings. Here, the authors aim at developing a rapid and easy digestion procedure, which may analyse and measure the total amount of sulphur in mine tailings by using inductively coupled plasma. For evaluating effects of several variables, the researchers used a univariate (analysis of variance (ANOVA)) strategy and considered factors such as composition of the acid mixture, heating time, and refluxing device to optimize the performance. To do the experiment, the researchers have used two certified reference materials (KZK-1 and RTS-2) and samples of tailings from Musselwhite mine. ANOVA result shows that heating time is the most influencing factor on acid digestion of the reference materials whereas in case of a digestion of tailings sample, hydrochloric acid proved to be the most significant parameter. Satisfactory results between the measured and referenced values are found for all experiments. It is found that the aqua regia (1 ml HNO₃ + 3 ml HCl) digestion of 0.1 g of samples after only 40 min of heating at 95°C produced fast, safe, and accurate analytical results with a recovery of 97% for the selected reference materials.