原子荧光光度法测定海水中硒的不确定度评定研究

通过实例对原子荧光法测定海水中硒的不确定度进行评定。根据(JJF 1059-1999)《测量不确定度评定与表示》中对测量和评定不确定度的要求评估了不确定度。测量不确定度的产生包括标准溶液的逐级稀释、工作曲线的非线性和原子荧光光度计的测量性能及取样体积。结果表明取样体积是导致该方法不确定度产生的主要影响因素,在测定时应加强这方面的控制,从而提高测量结果的准确性。当海水中硒的含量为1.99μg/L时,硒含量的扩展不确定度为0.40μg/L,置信水平为95%。     

原子荧光光谱法测定环境水体中痕量锡研究

在对环境水进行检测时,一个非常重要的项目就是对锡含量进行检测,所以,运用准确、灵敏的测定方法对环境水体中痕量锡进行检测具有非常重要的意义。文章将结合实验,在对环境水体中的痕量锡进行测定时,运用原子荧光光谱法,对测定环境水体中痕量锡的方法进行了一定的研究。采用原子荧光光谱法测定环境水体中的痕量锡,方法检出限是0.10μg/L,相对标准偏差0.20%~0.90%,实际样品加标回收率为98%~102%,满足环境监测实验室分析测定要求,值得推广。     

原子荧光光谱法测定环境空气中锑

采用过氯乙烯滤膜采集环境空气中锑,盐酸-氢氟酸混酸体系微波消解滤膜,原子荧光光谱法测定锑。方法前处理操作过程简单、省时、酸用量少、环境污染小,方法的灵敏度和准确度都有很大的提高。采样体积为300L时,空气中锑的最低检出质量浓度为0.002mg／m3。     

分散液液微萃取-气相色谱/质谱法测定水中阿特拉津

建立了简便、快速、有效的分散液液微萃取(DLLME)-气相色谱/质谱技术萃取水样中痕量阿特拉津的新方法。通过试验确定最佳萃取条件。     

固相萃取-原子荧光光谱法测定土壤中的砷

采用硝酸-氢氟酸-盐酸体系微波消解土壤并结合On-Guard ⅡH柱去除消解液中重金属,原子荧光光谱法测定土壤中的砷。本方法前处理操作过程简单、省时、省力、酸用量少,砷的加标回收率为94.4％～105.6％,能够满足环境监测分析的要求。     

均匀设计优化试验条件-原子荧光法测定污泥中总砷

通过对试验条件进行优化,建立了一种改进的氢化物发生-原子荧光光谱法测定污泥中总砷的方法。采用了均匀设计〔U10*(108)〕与单因子试验相结合以研究和优化分析参数和条件。在优化的试验条件下进行总砷含量的测定,方法检出限为0.21 mg kg-1,线性范围为0.24-100μg L-1,加标回收率在91.0%-94.5%之间。测定11份有证土壤样品(浓度值10.7±0.8 mg kg-1)的相对标准偏差(RSD,n=5)为1.6%。该方法经标准样品验证后,成功用于污泥实际样品的测定,并取得满意的结果。     

浙闽沿岸海域总溶解态无机锑的分布及影响因素研究

作为一种具有潜在致癌性的有毒稀有元素,锑已经广泛地存在于水体中并显现出较为严重的环境问题,引起科学界的广泛关注.利用氢化物发生原子荧光光谱法测定2008年5月浙闽沿岸海域水样中总溶解态无机锑(TDISb)的含量.结果表明,浙闽沿岸海域表、底层TDISb浓度的变化范围分别是0.68~5.64 nmol·L-1和0.71~5.25 nmol·L-1,平均含量分别为2.25、1.79 nmol·L-1,低于我国地表水环境质量标准和世界卫生组织规定的饮用水水质标准(约41.08 nmol·L-1).总溶解态无机锑表现出由沿岸向中央海区递减、表层高于底层的分布特征.影响浙闽沿岸海域溶解态无机锑分布的主要因素有水团混合,生物活动及悬浮颗粒物吸附解吸过程等.     

Evaluation of Bacillus sp. MZS10 for decolorizing Azure B dye and its decolorization mechanism

To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS10 strain, the cultivation medium and decolorization mechanism of the isolate were investigated. The decolorization was discovered to be dependent on cell density of the isolate and reached 93.55%(0.04 g/L) after 14 hr of cultivation in a 5 L stirred-tank fermenter at 2.0 g/L yeast extract and 6.0 g/L soluble starch and a small amount of mineral salts. The decolorization metabolites were identified with ultra performance liquid chromatography-tandem mass spectroscopy(UPLC-MS). A mechanism for decolorization of Azure B was proposed as follows: the C=N in Azure B was initially reduced to –NH by nicotinamide adenine dinucleotide phosphate(NADPH)-dependent quinone dehydrogenase, and then the –NH further combined with –OH derived from glucose to form a stable and colorless compound through a dehydration reaction. The phytotoxicity was evaluated for both Azure B and its related derivatives produced by Bacillus sp. MZS10 decolorization, indicating that the decolorization metabolites were less toxic than original dye. The decolorization efficiency and mechanism shown by Bacillus sp. MZS10 provided insight on its potential application for the bioremediation of the dye Azure B.     

Isolation and Identification of Antialgal Compounds from the Leaves of Vallisneria spiralis L. by Activity-Guided Fractionation (5 pp)

Background, Aims and Scope

Vallisneria spiralis Linn., a common, submerged macrophyte, is widely available in quiet waters of lakes, ponds, marshes and streams in Southeast Asia. V. spiralis plays a significant role not only in decreasing eutrophication of water body for its productivity, but also in inhibiting the growth of blue-green algae? The aim of the paper involves the isolation and identification of allelochemicals from extracts of V. spiralis by activity-guided fractionation and column chromatography.

Methods

Leaves of V. spiralis was washed free of debris, air-dried and refluxed in 95% EtOH. The extract was isolated using column chromatography and fractionation with antialgal activity. Potential allelochemicals were analyzed by high-resolution gas chromatography-mass spectrometry (HRGC-MS).

Results

Two fractions with strong antialgal activity were isolated using column chromatography and activity-guided fractionation from the extract of V. spiralis. 2-Ethyl-3-methylmaleimide, dihydroactinidiolide and 4-oxo-β-Ionone were identified in the first fraction, and 3-hydroxy-5,6-epoxy-β-ionone, loliolide, 6-hydroxy-3-oxo-α-ionone and an unknown compound in the second fraction. They had strong inhibitory effects on Microcystis aeruginosa Kütz.

Discussion

2-Ethyl-3-methylmaleimide is a byproduct of photooxidation of chlorophyll, and five other compounds identified were derivatives of β-carotene. HRGC-MS and derivatization technology were used to identify and confirm their molecular structures. The formula of the unknown compound was C16H19NO4. Metabolites of plant pigments had strong inhibitory activities on growth of algae.

Conclusions

Six compounds had been identified in V. spiralis, among them, 2-ethyl-3-methylmaleimide was the main allelochemical, and derivatives of ionone were also potential allelochemicals.

Recommendations and Perspective

. The results of our research could help us to study further mechanisms of inhibitory effect on algae and develop new potential antialgal substances.     

微纳米气液分散体系吸收NO

以模拟烟气为气源,去离子水为水源,通过微纳米气泡发生器形成微纳米气液分散体系,吸收模拟烟气中的NO,考察了多种因素对脱硝率(η)和气相体积总传质系数(KGa)的影响,分析了微纳米气液分散体系吸收NO的反应机理。结果表明:η和KGa随着进气NO体积分数和十二烷基苯磺酸钠(SDBS)质量浓度的提高而下降;随着吸收液初始pH的提高先降低后升高;随着进气O_2体积分数的增大而提高;随着吸收液温度的升高先提高后降低;控制进气NO体积分数为0.06%时,在吸收液初始pH为2.0、吸收剂为去离子水、吸收液温度为25℃、进气O_2体积分数为10%的最佳条件下,脱硝率可达81.0%。微纳米气液分散体系是通过产生羟基自由基从而对NO进行氧化吸收的。