荧光分光光度法测定废水中的微量硫化物

建立了一种基于荧光素汞在碱性条件下与S^2-作用生成荧光性的物质，从而使荧光素汞的荧光强度下降，根据荧光强度的下降值来测定水样中S^2-含量的方法，测定范围为0.007-0.8mg/L，线性相关系数r为0.9987。大部分共存物质不干扰测定，加入甲醛溶液可消除CN^-的干扰，加入酒石酸可消除Fe^3 的干扰，测定结果令人满意。     

氢化物发生-原子荧光法测定一次性餐具中砷

建立了一次性餐具中砷的氢化物发生－原子荧光测定方法，在选定的试验条件下，荧光强度与砷质量浓度在0μg/L－180μg/L范围内呈线性关系，相关系数0．999 3，溶液检测限0．5μg/L，回收率96％－101％。     

基于EEMs和DOM分离的荧光特征及DBPsFP研究 ——以南方某市水源水为例

以南方某市饮用水源地源水为研究对象,利用三维荧光-区域积分法(3D-EEMs-FRI)和DAX-8树脂富集分离技术,研究了水样各组分的溶解性有机物(DOM)组成特征、三维荧光光谱(3D-EEMs)特征;采用生成潜能测试,考察了典型消毒副产物三卤甲烷(THMs)和卤代乙酰胺(HAcAms)生成势以及其与水质指标和荧光强度...     

Heavy metals in Jamaican surface soils

A regional survey of Jamaican surface soils has been conducted in which more than 200 samples were collected at a sample density of 1 per 64 km² across the island and analysed for total concentrations of 31 elements by instrumental neutron activation analysis (INAA), energy dispersive X-ray fluorescence (EDXRF) analysis and atomic absorption spectrophotometry (AAS). The aim of the survey was to begin the construction of a high-precision geochemical database to provide information on elemental levels in soils for application to environmental studies, agriculture, and human and animal health. Results on the regional scale are presented for As, Cd, Cu, Hg and Pb. Although Jamaican surface soils are enriched in several heavy metals compared with world soil means and crustal abundances, lead is of particular importance at this stage because of its occurrence in residential areas. Except for Cu, the distribution maps of these elements are highly correlated with bauxite which in Jamaica is associated with white limestone geology and residualterra rossa soils.     

大沽河-胶州湾段溶解有机物类腐殖质荧光特征变化

利用荧光激发-发射矩阵光谱(excitation-emission matrix spectroscopy,EEMS)技术研究了溶解有机物类腐殖质荧光特征从大沽河到胶州湾的变化及其与盐度、pH、叶绿素a、溶解有机碳、化学需氧量和碳水化合物的关系.结果表明,大沽河溶解有机物类腐殖质荧光强度较大,胶州湾溶解有机物类腐殖质荧光强度较小,大沽河是胶州湾类腐殖质荧光物质的重要来源.类腐殖质荧光强度与叶绿素a含量的相关性较差,说明浮游植物并不是大沽河类腐殖质荧光物质的主要来源.类腐殖质荧光强度与溶解有机碳、化学需氧量和碳水化合物的相关性较好,说明类腐殖质荧光物质是水体溶解有机物的重要组成部分,其分布情况一定程度地反映了水体中有机物的分布.     

河流与海洋溶解有机物荧光激发-发射矩阵光谱的测定

通过对河流与海洋现场样品、微藻培养液和牛血清蛋白溶液的实验,确定了HITACHI F-4500型荧光分光光度计的测定河流和海洋溶解有机物荧光激发-发射矩阵光谱的激发和发射通带分别为5 nm和10 nm,波长扫描速度为12 000 nm/min,标准偏差在0.6%~8%。     

OH自由基与溴乙烷反应动力学和大气中存留寿命

溴代烷烃是破坏臭氧层的重要物质,用放电流动－共振荧光技术,测定ＯＨ自由基与Ｃ２Ｈ５Ｂｒ在２９７－３６９Ｋ温度范围的反应速率常数,求得其阿仑尼乌斯公式,并根据对流层的平均温度２２７Ｋ下求是ＯＨ自由基与溴乙烷反应速率常数（Ｋ）值,算出共在对流层的寿命为０．１６８ａ这将提供这类化合物使用否的重要科学根据。     

High-sensitivity direct analysis of aflatoxins in peanuts and cereal matrices by ultra-performance liquid chromatography with fluorescence detection involving a large volume flow cell

This paper reports a sensitive and cost effective method of analysis for aflatoxins B1, B2, G1 and G2. The sample preparation method was primarily optimised in peanuts, followed by its validation in a range of peanut-processed products and cereal (rice, corn, millets) matrices. Peanut slurry [12.5 g peanut + 12.5 mL water] was extracted with methanol: water (8:2, 100 mL), cleaned through an immunoaffinity column and thereafter measured directly by ultra-performance liquid chromatography-fluorescence (UPLC-FLD) detection, within a chromatographic runtime of 5 minutes. The use of a large volume flow cell in the FLD nullified the requirement of any post-column derivatisation and provided the lowest ever reported limits of quantification of 0.025 for B1 and G1 and 0.01 μg/kg for B2 and G2. The single laboratory validation of the method provided acceptable selectivity, linearity, recovery and precision for reliable quantifications in all the test matrices as well as demonstrated compliance with the EC 401/2006 guidelines for analytical quality control of aflatoxins in foodstuffs.     

Differences in U root-to-shoot translocation between plant species explained by U distribution in roots

Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 μmol U L⁻¹, distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot.