离子色谱法同时测定水中总氮和总磷

采用碱性过硫酸钾消解—离子色谱法同时测定水中总氮和总磷的含量。该方法避免了国标法中过硫酸钾和氢氧化钠对吸光度的干扰,对总氮和总磷测定的精密度有很大的提高。该方法在实验测定的浓度范围内总氮和总磷的相对标准偏差分别为3.84%和4.24%;总氮和总磷的最低检出限分别为0.007 mg/L和0.009 mg/L,比国标法更低;对实际试样总氮和总磷的加标回收率分别为92.6%～105.3%和94.7%～100.2%。     

微波消解-流动注射分光光度法测定总氮和总磷

以碱性过硫酸钾溶液为消解液,采用微波消解-流动注射分光光度法测定水中总氮和总磷。在碱性过硫酸钾溶液中氢氧化钠质量浓度为9.6g/L、微波功率为320W、消解管长度为16m的条件下,总氮和总磷的检出限分别为0.040m g/L和0.020mg/L,线性范围分别为0.040～3.500mg/L和0.020～2.500mg/L,相对标准偏差分别为1.6%和1.0%。微波消解-流动注射分光光度法应用于河水、湖水、化工废水等实际水样中总氮和总磷的测定,加标回收率分别为95.7%～98.1%和97.2%～102.2%。     

微波消解法测定水中总氮

总氮是衡量水质的重要指标之一。目前,总氮的标准测定方法是过硫酸钾氧化－紫外分光光度法。该法需要进行高温高压消解,不但消解过程耗时较长,而且操作比较繁琐。微波消解技术是近年来发展起来的新的消解方法。本法是用微波炉对水样进行消解,可缩短消解时间。本法与标准方法相比,总氮的测定结果相近。取总氮浓度已知的水样,分别在２～１５ｍｉｎ内进行微波消解试验,确定消解效果与时间的关系。结果表明,采用微波消解５ｍｉｎ即可消解完全。为确保各种水样消解彻底,本试验选择的消解时间为１０ｍｉｎ。取水样２份,分别进行６次平行…     

电力系统常用油品中磨损金属测定方法的研究

采用干、湿两种消解方法。进行了电力系统常用油品的消解方法研究，对消解后试液采用ICP／AES无机进样系统进行测定。通过对测定结果的统计、处理和汇总，以及方法精密度和准确度验证，最终得出了用直接燃烧灰化法代替ASTMD5708标准中的湿法消解来进行样品消解浓缩，使整个操作更为简便、省时。     

微波消解法测定农药废水中的总磷

介绍了一种测定农药废水中总磷的新的预处理方法－微波消解法。其消解时间从传统法的40min缩短到8min，精确度和准确度与传统的消解法相比无显著性差异。     

电导率测定中温度校正计算方法的改进

电导率测定中温度校正计算方法的改进在水质监测中电导率是一项重要的监测指标。根据标准监测分析方法，电导率的测定应在样品温度为２５℃时进行，当测定温度低于或超过２５℃时，需用规定的温度校正公式对测得的电导率进行校正。笔者在日常监测中发现：每次测定均需调温...     

流动注射分析在水体有机物监测中的应用

就近年来流动注射分析(FIA)在化学需氧量、酚类化合物、阴离子表面活性剂、有机磷农药等监测分析中的应用情况进行了归纳,并对FJA在水中有机物监测中常用的预处理技术如样品的在线消解、在线分离和预富集技术等做了介绍。     

氯离子对COD测定的干扰及校正方法的研究

采用标准曲线法，对Ｃｌ＾－在测定工业废水ＣＯＤ时的干扰进行校正。用重铬酸钾法测定不同浓度的纯ＮａＣｌ溶液的ＣＯＤ，将测定结果绘成标准曲线，由水样测定的ＣＯＤ减去由标准曲线查得的Ｃｌ＾－校正值，即得到水样的真实ＣＯＤ。该方法简捷、方便、不使用剧毒试剂ＨｇＳＯ４，适用于含Ｃｌ＾－５００－２５０００ｍｇ／Ｌ废水ＣＯＤ的测定。     

用开管法快速测定废水的COD

介绍了用硫酸锰代替硫酸银作催化剂快速开管测定废水COD的方法．最佳测定条件为：消解温度170℃,消解时间12min,酸度11mol／L,催化剂(硫酸锰)用量10g／L。该方法使试样的消解时间由标准法的2h缩短到12min,同时用硫酸锰代替价格昂贵的硫酸银可大大降低分析成本,而准确度和精密度与用硫酸银作催化剂的开管法基本相同,COD测定下限为65mg／L。该方法可同时消解多个试样．适用于大批量水样的测定。     

用反应完毕后定量稀释法测定水中高浓度砷的探讨

用比色法测定水中砷浓度时,因预料不到其浓度高低,常出现试样砷浓度超过测定上限(0.5毫克/升)的情况,影响测定结果。对于这种情况,通常是采用少取试样、稀释后重新于砷化氢发生瓶中反应1小时、再测定吸收液吸光度的方法(简称甲法)。该法不但费时、费事,而且不利于大批样品的测定。根据多年应用甲法测定水中砷浓度的经验,我们探讨了一种改进的测定高浓度砷水样的方法,即在试样于砷化氢发生瓶中反应完毕后,将吸收液用氯仿进行定量稀释,再     

基质固相分散萃取—气相色谱法测定土壤中有机氯农药含量

建立了一种基质固相分散萃取—气相色谱法测定土壤中8种有机氯农药含量的方法,优选了固相分散剂及其用量、洗脱溶剂以及土壤样品与分散剂的质量比。实验结果表明,在弗罗里硅土作为分散剂、正己烷和丙酮（体积比为1∶1）为洗脱溶剂、土壤样品与分散剂的质量比为1∶3的优化条件下,8种有机氯农药在50~250 μg/kg范围内表现出良好的线性关系,相关系数大于0.99,加标回收率为60.3%~94.3%,相对标准偏差为6.83%~8.95%。实际土壤质控样测试结果显示,本方法的测试结果在标准值的不确定度范围内,可满足土壤中有机氯农药残留的检测分析。     

改进气相色谱法测定总烃与非甲烷总烃

采用十通阀、双定量环进样(进样量0.5 m L),专用的甲烷柱和总烃柱分别分离两路气样,单FID检测器检测的方法测定环境空气和固定污染源废气中的总烃和非甲烷总烃(NMHC)。实验结果表明:总烃与甲烷工作曲线的相关系数分别为0.997 7和0.999 0;总烃与甲烷测定结果的相对标准偏差均未超过1.5%;总烃与NMHC的检出限均为0.04 mg/m~3;总烃的加标回收率为90.3%~113.0%,NMHC的加标回收率为91.1%~110.0%。上述指标均满足HJ 604—2011和HJ/T 38—1999中对总烃及NMHC的测定要求。用注射器采样后的气样应尽量避光保存,放置时间宜在8 h之内。该方法无需制备除烃空气,大幅提升了检测效率。     

Ultimate analysis and heating value prediction of straw by near infrared spectroscopy

Ultimate analysis and heating value determination are two of the most important routine analyses for exploiting agricultural wastes for energy conversion. The use of near infrared spectroscopy (NIRS) was investigated as an alternative method to predict the carbon, hydrogen, and nitrogen content and the heating value of straw. A total of 222 straw samples, collected from 24 provinces of China, were used for NIRS calibration and validation in this study. The $R_{\text{v}}^2$ and standard error of predictions in independent validation were, respectively, 0.97 and 0.37% for C, 0.77 and 0.17% for H, 0.87 and 0.10% for N and 0.96 and 181 J/g for heating value. A multiple linear regression (MLR) model was also built to predict the heating value from the contents of C, H and N. The MLR equation gave good prediction (standard error of prediction = 224 J/g) when evaluated using the same validation set as the NIRS. Therefore, rapid analysis of straw can be achieved through the constructed equations, saving analytical time and cost.     

An assessment of municipal solid waste compost quality produced in different cities of India in the perspective of developing quality control indices

A study was conducted to investigate physico-chemical properties, fertilizing potential and heavy metal polluting potentials of municipal solid waste composts produced in 29 cities of the country. Results indicated that except a very few samples, all other samples have normal pH and EC. Organic matter as well as major nutrients N and P contents in MSW composts are generally low as compared to the composts prepared from rural wastes. Heavy metal contents in composts from bigger cities (>1 million population) were higher by about 86% for Zn, 155% for Cu, 194% for Cd, 105% for Pb, 43% for Ni and 132% for Cr as compared to those from smaller cities (<1 million population). Composts prepared from source separated biogenos wastes contained, on average, higher organic matter (by 57%), total N (by 77%) and total P (by 78%), but lower concentrations of heavy metals Zn (by 63%), Cu (by 78%), Cd (by 64%), Pb (by 84%), Ni (by 50%), and Cr (by 63%) as compared to those prepared from mixed wastes. Partial segregation at the site of composting did not improve quality of compost significantly in terms of fertilizing parameters and heavy metal contents. Majority of MSW composts did not conform to the quality control guideline of ‘The Fertilizer (Control) Order 1985’ in respect of total organic C, total P, total K as well as heavy metals Cu, Pb and Cr. In order to enable the relevant stakeholders to judge overall quality, a scheme has been proposed for the categorization of composts into different marketable classes (A, B, C, and D) and restricted use classes (RU-1, RU-2, and RU-3) on the basis their fertilizing potential and as well as potential for contaminating soil and food chain. Under the scheme, ‘Fertilizing index’ was calculated from the values of total organic C, N, P, K, C/N ratio and stability parameter, and ‘Clean index’ was calculated from the contents of heavy metals, taking the relative importance of each of the parameters into consideration. As per the scheme, majority of the compost samples did not belong to any classes and hence, have been found unsuitable for any kind of use. As per the regulatory limits of different countries, very few compost samples (prepared from source separated biogenos wastes) were found in marketable classes (A, B, C and D) and some samples (11–14) were found suitable only for some restricted use.     

浊点萃取分光光度法测定水中Cr(Ⅵ)

利用二苯碳酰二肼显色,Triton X-100-正辛醇浊点萃取,建立了一种分光光度法测定水中Cr(Ⅵ)的新方法,并探讨了不同测定条件对测定效果的影响。优化后的测定条件为(总体积50 mL)1 mol/L稀硫酸加入量1.0mL、2 g/L二苯碳酰二肼溶液加入量1.5 mL、10 g/L Triton X-100溶液加入量1.5 mL、3 g/L苯甲酸溶液加入量4.0mL、正辛醇加入量5.0 mL。Cr(Ⅵ)质量浓度在0~20μg/L范围内符合朗伯-比尔定律,线性回归方程的相关系数为0.995 5。该方法应用于水样中痕量Cr(Ⅵ)的测定,相对标准偏差小于2.5%,加标回收率为95.7%。     

内标法与外标法测定废气中挥发性有机化合物

目前采用热脱附-气相色谱-质谱法测定废气中挥发性有机化合物时多使用外标法。实验对比了内标法与外标法测定时存在的差异,发现大多数VOCs内标法的回收率均高于外标法,且内标法的相对标准偏差普遍小于外标法,内标法测定的准确度和精密度均优于外标法。内标法的标准曲线可使用更长时间,对于大量样品的测定非常有利;而外标法必须每次测定时重新绘制新曲线。故废气中VOCs测定工作推荐使用内标法定量。     

废水污染物排放总量控制指标的确定及控制对策

着重论述了株洲化工集团有限责任公司废水污染物排放总量控制指标的确定方法,并简述了排放总量控制对策。     

固相微萃取—气相色谱法测定水中痕量硝基苯类化合物

建立了固相微萃取种类与气相色谱联用测定地下水中12种硝基苯类化合物的分析方法,对萃取头种类、萃取时间、萃取温度、进样口衬管种类等分析条件进行了优化。实验结果表明,该方法的检出限为0.001~0.050 μg/L,线性范围0.005~500 μg/L（相关系数大于0.997）,加标回收率为72.1%~122.0%,相对标准偏差为3.65%~12.60%。应用该方法对地下水及地表水样品进行分析,结果表明该方法具有环保、灵敏、快速、简便等特点,适用于水中痕量硝基苯、硝基甲苯类化合物和硝基氯苯类化合物的测定。