原子荧光法测定土壤中的汞

建立了原子荧光光度计测定土壤中汞的分析方法，对影响土壤中汞测定的各种因素，如空白值的控制、样品的消解、共存离子的干扰和标准溶液的存放等作了研究，从而提出了土壤中汞测定的最佳条件及分析方法。     

总氮测定中的注意事项

碱性过硫酸钾消解紫外分光光度法测定总氮中，对空白值偏高的影响因素进行了实验和分析，提出了几点建议及改进措施。     

水质总氮测定中的有关问题探讨

对总氮测定中的一系列影响因素,诸如实验用水,器皿的洗涤,实验室环境试剂的提纯、配制和保存,消解温度、压力和时间的控制,以及高氨氮水样中的总氮测定、总氮、总磷的同时测定和其他有关的问题,作了较为详细的探讨,并提出了相应的解决办法。     

测定总氮时影响空白吸光值的因素

针对测定水质中总氮时遇到实验空白值偏高的情况，分析了实验用水、试验及环境因素对空白值的影响。     

实验室测定二氧化硫的影响因素

空气二氧化硫的测定,对实验室测定条件比较敏感,通过实验表明,显色时间、显色温度、PRA纯度、蒸馏水质量等条件,均对其校准曲线的斜率和空白值有影响,所以在实验分析过程中,必须严格把握操作条件,严格遵循操作步骤。     

水和废水中总氮测定的关键问题研究

结合环境监测工作的实际,应用国标经典分析方法——《碱性过硫酸钾氧化-紫外分光光度法》（GB11894—1989）,对水和废水中总氮的测定进行了系统的研究。概述了方法的原理,简介了方法的分析步骤,深入探讨了运用该方法进行水和废水中总氮测定的一些关键操作技术问题,指出在标准分析方法的基础上,选用纯度较高的过硫酸钾,提高氧化消解温度至126—127℃,延长过硫酸钾的氧化消解时间至50min,消解后自然冷却2—3h,能确保水样总氮分析的精密度和准确度。     

降低水质氨氮测定中试剂空白值的方法

氨氮的测定通常采用纳氏试剂比色法,该法具有操作简便、灵敏等特点。但我们在日常分析水样中普遍发现,有时所购买的抗金属干扰掩蔽剂酒石酸钾钠试剂含氨较高,造成该方法试剂空白值增高,试剂空白值吸光度大于0.06。由于试剂空白值较高,因此给分析结果带来误差。本文采用纳氏试剂对50％的酒石酸钾钠溶液进行提纯,方法简便易行,解决了以上问题,使试剂空白吸光度降至小于0.025,取得满意效果。     

关于4-氨基安替比林萃取光度法测定挥发酚的探讨

介绍了在测定挥发酚过程中,对试剂的保存、缓冲溶液pH值的控制、各种试剂的加入顺序及萃取时间等存在的问题,并针对性地提出了解决办法.     

两种方法测定固体废物中的总氮

对固体废物中总氮含量的测定方法进行了研究，用修正的凯氏法消解作比较、凯氏定氮仪定氮，纳氏试剂分光光度法和滴定法分别测定铵态氮，对国家标准土样GSS-7及实际的不同含氮固体废物样舄的测定值进行F检验和t检验，结果表明，两种测定方法间的精密度与准确度均无显著性差异，修正的凯氏法-纳氏试剂分光光度法及修正的凯氏法-滴定法均适用于测定固体废物中的总氮。     

自配消解液分光光度法测定污水中的COD

以自配消解液代替ThermoFisher公司AQ4001COD测定系统的专用消解液,比较了自配消解液分光光度法与国家标准重铬酸钾法(GB 11914-1989)测定化学需氧量(COD)的差异。对比试验表明,自配消解液分光光度法测定COD的结果精确度和准确度高,与国家标准方法无显著性差异。自配消解液分光光度法测定水样COD值的相对标准偏差;低量程(30～150 mg/L)为1.38%～2.53%,中量程(0～1 500 mg/L)为0.47%～3.63%,高量程（2 000～15 000 mg/L）为0.17%～3.53%,在国家标准方法测试水样COD值的允许误差范围内。除制革废水外,自配消解液可以代替AQ4001COD测定系统的专用消解液,适用不同量程范围内污水COD的测定。自配消解液分光光度法具有试剂使用量少、速度快、经济、二次污染小等优点,值得在环境科学领域及废水水质监测中推广应用。     

次溴酸盐氧化法测定海水氨氮影响因素的探讨

测定海水中氨氮时,经常会出现曲线线性不好、空白值高等情况。文中通过对实验室环境、实验用水、器皿、试剂、操作过程等因素进行分析探讨,找出了实验出现问题的原因,并进行了校正。     

Adjusted blank correction method for UV–vis spectroscopic analysis of PTIO-coated filters used in nitrogen oxide passive samplers

Passive sampling devices are popular in applications which do not require the monitoring of hourly concentrations. Nitrogen oxides are often collected using filters coated with 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO). The filter extract can then be analyzed using flow injection analysis ion chromatography fitted with a copper/cadmium reduction column or UV–vis spectroscopy. When the latter is used to measure low concentrations of nitrogen oxides, absorbance by PTIO at the analytical wavelength of 545 nm contributes significantly. PTIO concentration on the filter also shows variation with filter storage and exposure time not accounted for in a single point blank subtraction at the analytical wavelength. A method is presented that uses a scaling factor to account for variations in concentration of PTIO on the field blank and provides a more accurate method for determining and correcting for the PTIO contribution to absorption when measuring ambient nitrogen oxide concentrations.     

Determination of Sulfur Oxides in the Flue Gases of the Pulping Processes

The body of information presented in this paper is directed to the operating personnel and process engineers employed in the power and recovery departments of a chemical pulping operation. The proper evaluation of the total analytical and sampling system (TASS), to be used in the determination of sulfur oxides is as important as a proper analytical and recording system (ARS). The presence of other sulfur gaseous compounds and particulates could greatly influence the results of the determination.

The analytical method employed determines sulfur dioxide and trioxide from an aliquot of the trapping solution, 3% hydrogen peroxide and 8 0% isopropyl alcohol respectively. The aliquot is titrated with barium perchlorate in the presence of Thorin indicator. The results of evaluating the method indicated negligible interference from the presence of hydrogen sulfide, mercaptans and nitrogen oxides. A blank correction of 15 parts per million (ppm) is recommended whenever 100 ppm of hydrogen sulfide or more are simultaneously present in the gas stream. Particulaies are shown to interfere either by addition or subtraction. Sulfate particulates that will add to the determination must be removed, but in doing so, care must be exerted to avoid surface-contacting conditions that promote reaction between carbonates and the sulfur oxides. The integrated method of sampling and analysis will permit determinations from a flue gas with sulfur oxides concentrations of 30 ppm and above. The relative standard deviation improves from 10% at 100 ppm SO₂ to 2.6% at 1000 ppm SO₂. In both cases, sulfides were present.     

Quantitative analysis of environmental factors in differential weighing of blank Teflon filters

Mass differences less than 100 microg must be correctly measured in gravimetric analysis of particles collected on filters. Even small variations in mass measurement may contribute significant errors to calculated concentrations. In addition to the collected particles, a number of other factors affect the observed mass difference between the measurements before and after sampling. The most often controlled of these factors are static charge, temperature, and humidity. Using 951 laboratory blank filter weights, we have statistically analyzed these and other factors that affect the observed filter weight. Some of these are controllable or correctable; others are not and enter into the final results as errors. The standard deviation of differential blank filter weighing after applying all corrections was 2.7 microg. The most important correctable factors are air buoyancy variation and filter storage time. When weighing blank Teflon filters at relative humidity < 50%, these are an order of magnitude more important than weighing-room humidity. Using field blank filters in each weighing batch could control these three factors but also doubles the errors caused by balance random variation and filter handling contamination, because four weighing measurements and the handling of two filters are needed to obtain one corrected differential mass result.     

Determination of the molecular weight of fulvic acids by UV/VIS spectroscopy

Partial least squares (PLS) modeling was applied to investigate number-average molecular weights (Mn) and weight-average molecular weights (Mw) of fulvic acids (FAs) in relation to the corresponding UV/VIS spectra. The Mn and Mw values were determined by size exclusion chromatography (SEC). The impact of pH control, wavelength range and density as well as smoothing and derivation of spectra were tested. It was found that PLS models based on absorbance spectra can be a fast and powerful complement to existing techniques employed for determination of molecular weights of FAs. Control of pH of the FA solutions is important for the performance of the models. The models were also compared with the best univariate alternatives.     

影响分析空白值的因素及控制措施

化学实验中,经常会出现空白值异常的情况。文中从可能对空白值产生影响的各个因素逐一进行分析,并在此基础上提出了控制空白值的手段和措施。     

接种稀释水的空白对BOD_5测定的影响

从接种液种类、空白 BOD5大小、接种液最佳添加范围等方面对 BOD5测定进行探讨 ,提出以接纳工业废水的河水作为最佳接种液 ,雨季时以土壤浸取液更适合。探讨了接种液空白值对 BOD5标液和工业废水的影响。结果表明 ,河水空白应控制在 0 .1～0 .8mg/ L,土壤浸取液空白控制在 0 .0 1～ 0 .1 0 mg/ L为宜。     

Spectrophotometric determination of the fungicide captan

A spectrophotometric method for the determination of the fungicide captan has been developed based on its reaction with thiosemicarbazide. The absorbance was measured at 315 nm. The effects of the proportion of water, thiosemicarbazide concentration, pH and temperature on this reaction was studied to select the best chemical conditions. The calibration graph was obtained between 1.2 and 30 ppm and the detection limit is 0.5 ppm. The RSD (n = 10) was 1.34%. Possible interference of various pesticides was examined. The method was applied to the determination of captan in agrochemical formulations. Results agree well with the labelled values and also with results that were obtained by a polarographic method.     

改良型Carrousel氧化沟工艺生物脱氮除磷效果研究

为了提高改良型Carrousel氧化沟工艺污水处理厂的脱氮除磷效果,结合某污水处理厂3年的运行实践,讨论了该工艺的处理效果,生物脱氮除磷原理及影响出水效果的因素.分析表明将DO控制在0.3～0.7 mg/L范围内,能够使出水中的TN浓度低于20 mg/L;在氧化沟中发生的同步硝化反硝化反应(SND)对总氮的去除的贡献占总系统脱氮的66%;该系统剩余污泥的含磷率为3.0%,生物细胞中平均含磷量可达细胞干重的4.2%;总磷去除率与污泥龄具有很好的线性关系,加大污泥排放量可以提高除磷效果.