差减法和直接法对水中总有机碳测定结果比较

为了比较差减法和直接法对水中总有机碳测定结果,分别配制差减法和直接法的工作曲线,并分别通过差减法和直接法对不同水体中的总有机碳含量进行测定。比较测定结果,发现差减法和直接法对较清洁水体样品的TOC测定结果误差不大,而对废水样品的TOC测定结果误差较大。     

大气颗粒物中元素碳的直接测定

对原来用元素分析仪测定大气颗粒物样品中有机碳、元素碳的方法[1 ] 进行改进 ,将差减法间接测定元素碳改为一步直接测定元素碳。有机碳、元素碳的测量标准偏差的平均值分别为 0 35 %、0 34% ,提高了元素碳的测量精度 ,同时避免了误差传递 ,解决了差减法测定元素碳时出现负值的情况。     

呼伦贝尔地区草原表层土壤中总有机碳与有机质初探

通过非分散红外线吸收法测定呼伦贝尔地区具有代表性的16个草原表层土壤(0~20 cm)中总有机碳、溶解性有机碳,使用重铬酸钾容量法测定有机质,并对其总有机碳与有机质水平及两者相关性进行了分析。初步分析了造成各样品之间总有机碳水平差异的原因。结果表明,只以打草场作为利用方式的土壤总有机碳含量较常年放牧场的总有机碳含量高。从草原类型和土壤类型上看,草甸草原总有机碳含量明显高于典型草原,黑钙土总有机碳含量明显高于栗钙土。综上,过度放牧会使草原土壤总有机碳大量释放。总有机碳含量与有机质含量有显著正相关性,相关系数达到0.902。     

大气总悬浮颗粒中有机碳的测定

本文提出一种新的高灵敏度测定总悬浮颗粒中有机碳的方法一元素分析法。该方法是在氧化炉最佳温度为６００℃时，一步测定出样品中有机碳的含量，并成功地对齐齐哈尔市大气总悬浮颗粒中的有机碳进行了连续的监测。结果表明，总悬浮颗粒中有机碳的含量有较明显的变化规律。     

大气颗粒物样品中有机碳和元素碳的测定

采用元素分析仪测定大气颗粒物样品中有机碳、元素碳。应用商业化仪器元素分析仪 ,在燃烧炉温度为 4 50°C时 ,一步测出样品中有机碳的含量 ;再运用加酸的方法除去样品中的碳酸盐 ,然后在燃烧炉温度为 950°C时测出样品中有机碳、元素碳含量之和。通过差减计算 ,得出元素碳的值。有机碳、元素碳测量的标准偏差平均值分别为 0 2 5%、0 50 %。     

高温红外吸收法测定水煤浆中可燃硫方法研究

研究采用高温红外吸收法直接测定水煤浆中可燃硫方法,确定了用浆状水煤浆试样或粉末固体试样的样品制备和红外测硫仪的炉温设定范围(900℃～950℃),通过与间接差减法测定结果对比分析,表明此法可行.     

利用TOC-5000A总有机碳分析仪测定环境水样中包含全部颗粒态有机碳的研究

本文结合TOC总有机碳分析仪和SSM固体样品燃烧装置各自的特点，探索了测定环境水样中包含全部颗粒态有机碳的测定方法．此方法能够全面反映环境水样中总有机碳的含量     

氯化铵-火焰原子吸收光谱法测定地表水中的总铬

应用原子吸收法测定水样中的总铬，在不同条件下对空白样品、标准样品和实际样品进行试验分析，进一步验证了方法的准确度和精密度，加标回收率在96.8%-103%之间，相对标准偏差为2.1%。试验表明，该方法准确可靠，实际操作具有可行性，适用于工业废水和受污染地表水中总铬的测定。     

异烟酸——吡唑啉酮光度法测定高浓度总氰化物的初探

用零浓度空白管经显色后的试液作稀释液，对高浓度总氰化物显色后的样品进行稀释分析测定，这样可提高高浓度总氰化物测定结果的淮确度和精密度，与直接稀释法测定的结果等效。     

京杭大运河(苏北段)底泥中汞的总量与形态的分布研究

对京杭大运河(徐州段)底泥中的18个样品进行研究,分别用冷原子荧光仪和总有机碳测定仪测定,对底泥中的汞的总量和形态进行测定.结果表明,汞在底泥中的含量主要以残渣态存在,可交换态很少,占总合量的0.04%～1.839%,总有机碳的含量与汞的总量分布没有相关性.     

Optimizing the weight loss-on-ignition methodology to quantify organic and carbonate carbon of sediments from diverse sources

The sequential weight loss-on-ignition (WLOI) method for determination of organic and carbonate or inorganic carbon (C) content was evaluated on sediments from diverse sources with a great range of C contents. The sediments were collected from canal, wetland, river, estuary, lake, and marine sites. The organic and inorganic C contents of these samples ranged from 1 to 430 g kg^???1 and from 4 to 97 g kg^???1, respectively. Combinations of the combustion time and temperature and optimal weight ranges of representative samples were tested, and comparisons of the WLOI method with other methods, including dry combustion and wet combustion, were made. These methods were (1) use of the carbon?Cnitrogen?Csulfur (CNS) autoanalyzer with normal and reduced temperatures for total and organic C, (2) thermogravimetry for both organic and inorganic C, (3) use of the CNS autoanalyzer after removal of inorganic (carbonate) C by fumigating samples with concentrated HCl for organic C, (4) Walkley?CBlack wet combustion method for organic C, and (5) pressure-calcimeter associated with subtraction method (total C minus inorganic C) for organic C determinations. The results of analyzing samples of sediments of diverse origins showed that the optimal combination of temperature and time of WLOI depended mostly on the sources of the analyzed sediment. The WLOI analysis of sediment samples for organic C from wetlands, canal, estuary, or river sites needed a relatively low temperature but that of sediment samples from lake and marine sites required a relatively high temperature. Overall, to obtain reliable analysis results of samples from widely varied sediment sources except marine sediments, 500°C for 12 h was optimal for organic C content determination, and 800°C for yet another 12 h was optimal for inorganic C content determination. The temperature could even be reduced to 475°C if only wetland and stream sediments were included, but for marine sediments, 550°C for 12 h was necessary. Precise C content determinations for most sediment sources could be obtained by WLOI when sample quantities ranged from 2.0 to 4.0 g. The WLOI method, when conducted properly, resulted in precise measurements of C contents in ??standard samples?? used for calibration, and these values were closely comparable to results obtained with other dry combustion methods (R ²????0.96). We conclude that WLOI, which has advantages of simplicity, cost-effectiveness, and no waste disposal over other methods, can provide precise measurements of organic and inorganic C contents in sediments from a wide range of sources, but the selection of heating temperature and exposure time should be carefully considered based on sediment sources.     

Assessment of relative accuracy in the determination of organic matter concentrations in aquatic systems

Accurate determinations of total (TOC), dissolved (DOC) and particulate (POC) organic carbon concentrations are critical for understanding the geochemical, environmental, and ecological roles of aquatic organic matter. Of particular significance for the drinking water industry, TOC measurements are the basis for compliance with US EPA regulations. The results of an interlaboratory comparison designed to identify problems associated with the determination of organic matter concentrations in drinking water supplies are presented. The study involved 31 laboratories and a variety of commercially available analytical instruments. All participating laboratories performed well on samples of potassium hydrogen phthalate (KHP), a compound commonly used as a standard in carbon analysis. However, problems associated with the oxidation of difficult to oxidize compounds, such as dodecylbenzene sulfonic acid and caffeine, were noted. Humic substances posed fewer problems for analysts. Particulate organic matter (POM) in the form of polystyrene beads, freeze-dried bacteria and pulverized leaf material were the most difficult for all analysts, with a wide range of performances reported. The POM results indicate that the methods surveyed in this study are inappropriate for the accurate determination of POC and TOC concentration. Finally, several analysts had difficulty in efficiently separating inorganic carbon from KHP solutions, thereby biasing DOC results.     

Disinfection by-product formation and mutagenic assay caused by preozonation of groundwater containing bromide

Brominated organic and inorganic by-products are generated during ozonation of groundwater containing high bromide concentrations. This study measured concentrations of bromate, bromoform, bromoacetic acids, bromoacetonitriles, bromoacetone, 2,4-dibromophenol and aldehyde generated by ozonation. The potential mutagenicity of ozonated waters was assessed using the Ames and Microtox tests. Test results for the 18 ozonated groundwater samples demonstrate that bromate formation is associated with high pH, bromide and alkalinity content, low levels of dissolved organic carbon (DOC) and ammonia, and low alkalinity. Brominated organic by-products were correlated with high bromide ion and natural organic matter content, and low ammonia concentrations. The Ames test results demonstrate that all extracts from ozonated water have mutagenic activity; however, the 18 raw groundwater samples had no mutagenicity. The Microtox test results also show that the ozonated water samples were highly toxic. Generally, both bromide and DOC content promoted the formation of ozonation by-products and mutagenicity. Controlling of bromide and DOC concentrations is an effective method of reducing potential by-product formation and eliminating mutagenicity problems associated with groundwater ozonation.     

Multi N/C2100S总有机碳分析仪校准方法的建立

以德国Analytikjena公司Multi N/C 2100S分析仪为例,研究建立了合理可行的总有机碳分析仪校准方法.在总有机碳分析仪检定规程JJG 821-2005的基础上,增加零点漂移、直线性、标准曲线线性和检出限4项特性指标,改变了准确性特性的判定方法.根据仪器的使用频率和稳定性,建议校准周期不超过2年.     

南通市区河流底泥营养物质污染特征及环境风险分析

以南通市区的学田河、南川河、法伦寺河、城山河及西山河为研究对象,测定了河流表层底泥中的有机质、总氮、氨氮、硝氮、总磷、无机磷及活性有机磷等营养物质指标,分析了污染最重的监测点的污染原因。此外,采用有机指数法、营养物质比值法进行了环境风险评价。得出各条河流底泥均为肥污染级,尤其污染最重的是西山河;各研究河流底泥的碳氮比都很高,说明其营养物质主要来源于周围环境;学田河和西山河底泥的氮磷比较高,说明它们的富营养化程度相对较高。通过回归分析,得出学田河、南川河、法伦寺河及城山河底泥中有机质与总氮及南川河有机质与总磷之间具有良好的线性相关性。     

红枫湖水体中碳的时空分布特征分析

基于2013年8月、10月、11月及2014年3月在红枫湖5个表层水样采集点、3个分层水样采集点测定的总碳、无机碳、总有机碳及二氧化碳数据,结合当时的气象数据对碳的时空分布特征讨论分析。结果表明,虽然调查期间同时间相同水层各个水样采集点的上述4个指标差异并不明显,但同一时间不同分层水体及各水样采集点不同季节在碳分布上存在一定差异。温度越高,光照越长,生物活性越强,湖体碳被生物利用的比例越大,总碳、无机碳、总有机碳含量就越低,较强的生物活性也伴随更多的二氧化碳产生。上、下层水体因光与温度差异所导致的碳分布差异会因季节性翻湖而消失。     

Variation of total organic carbon content along the stream Harsit, Eastern Black Sea Basin, Turkey

The TOC in surface waters and wastewater is an important analytical parameter describing the total content of all organic substances containing carbon. In practice, the TOC originated from natural and anthropogenic sources, and even if it is not directly responsible for dangers on human health, its determination is important for any kind of water that is used by public. The aim of this study was to determine variation of total organic carbon (TOC) and total carbon (TC) content in the stream Harsit, which courses in Eastern Black Sea Region, Turkey. Sampling was fortnightly conducted in each of the four seasons between March 2009 and February 2010. A total of 230 water samples were collected from ten sampling stations along the main branch of the stream Harsit with 143 km of length. Obtained TOC values were evaluated and used to classify the water quality of stream Harsit, according to the Turkish Water Pollution Control Regulation (TWPCR). The annual average TOC content values for the stations were found between 2.33 and 6.97 mg/L. It was seen that the TOC content have increased along the streamcourse of Harsit until the fourth station, where reaches its maximum value. The TOC content, then, has decreased and the minimum value was observed in the eighth station. The results showed that, except in winter season, maximum TOC content observed in many of the water samples were above Class I water standard indicated in TWPCR, which classifies the water resources according to the different area of uses. It was also found that TOC has a small contribution to TC and the highest TOC content in stream waters were measured in Gumushane station where direct discharge of city wastewaters and solid waste dumping to the stream were observed.     

用直接加热代替水浴加热测定高锰酸盐指数

在地表水高锰酸盐指数酸性法分析中，通过对2种加热方法的实验对比，结果表明，直接加热法具有省时、省力，且精密度、准确度均能满足环境监测规范要求等优点，特别适用于大批量样品分析。