广东省海域经济鱼类的重金属污染及其评价

样品中各元素原位、微区、高分辨率的空间分布特征具有现实而重要的研究意义. 在生物样品中,元素原位空间分布特征可以作为生理过程的指示指标,揭示代谢途径,并可反映周围环境特征对生物体的影响方式. 在地质样品中,元素原位空间分布特征可以作为矿产评估依据,也可作为研究环境地球化学变化过程的重要指标. 目前常用的几种微区元素原位分布特征测试技术包括：微区XRF技术（μXRF）、同步辐射技术（SR）、能谱电子显微镜联用技术（EM-EDS）、电子探针技术（EP）、激光剥蚀联用电感耦合等离子体质谱技术（LA-ICP-MS）、激光诱导击穿等离子发射光谱技术（LIBS）等. 根据其测试原理,这些技术在是否无损、是否定量检测、适合样品类型和大小、前处理方式复杂程度、检出限高低、分辨率大小等方面存在差异. 介绍和总结了当前主流的微区原位元素分布检测技术,分析比较了各种技术的优缺点及其适用的样品类型和应用范围,对标准样品的选择、数据校准处理及可视化成图等方案进行初步探讨,为相关的科研分析工作提供技术参考.     

Green Extraction Processes for Complex Samples from Vegetable Matrices Coupled with On-Line Detection System: A Critical Review

The detection of analytes in complex organic matrices requires a series of analytical steps to obtain a reliable analysis. Sample preparation can be the most time-consuming, prolonged, and error-prone step, reducing the reliability of the investigation. This review aims to discuss the advantages and limitations of extracting bioactive compounds, sample preparation techniques, automation, and coupling with on-line detection. This review also evaluates all publications on this topic through a longitudinal bibliometric analysis, applying statistical and mathematical methods to analyze the trends, perspectives, and hot topics of this research area. Furthermore, state-of-the-art green extraction techniques for complex samples from vegetable matrices coupled with analysis systems are presented. Among the extraction techniques for liquid samples, solid-phase extraction was the most common for combined systems in the scientific literature. In contrast, for on-line extraction systems applied for solid samples, supercritical fluid extraction, ultrasound-assisted extraction, microwave-assisted extraction, and pressurized liquid extraction were the most frequent green extraction techniques.     

采用毛细管电泳电堆集富集技术分离与测定雪样中的痕量阳离子

以咪唑为背景电解质,以α－羟基异丁酸和１８－冠醚－６为络合剂,采用毛细管离子电泳间接紫外法,研究了发样中痕量ＮＨ４＾＋、Ｋ＾＋、Ｃａ＾＋、Ｍｇ＾２＋分离与测定的方法。通过向缓冲液中加入甲醇,使Ｃａ＾２＋、Ｎａ＾＋迁移顺序发生反转,有利于在Ｃａ＾２＋的浓度较高时少量Ｎａ＾＋的测定。采用电堆集富集技术,各离子的检测限达１×１０＾－７ｍｏｌ／Ｌ。以Ｌｉ＾＋作为内标,采用标准加入法对地样中的痕量阳离子进行     

Influences of evolved gases on the thermal decomposition of zinc carbonate hydroxide evaluated by controlled rate evolved gas analysis coupled With TG

The influences of atmospheric CO₂ and H₂O on the kinetics of the thermal decomposition of zinc carbonate hydroxide, Zn₅(CO₃)₂(OH)₆, were investigated by means of controlled rate evolved gas analysis (CREGA) coupled with TG. Although CO₂ and H₂O were evolved simultaneously in a single mass-loss step of the thermal decomposition, different effects of those evolved gases on the kinetic rate behavior were observed. No distinguished effect of atmospheric CO₂ was detected within the possible range of self-generated CO₂ concentration. On the other hand, apparent acceleration effect by the increase in the concentration of atmospheric H₂O was observed as the reduction of reaction temperature during the course of constant rate thermal decomposition. The catalytic effect was characterized by the decrease in the apparent activation energy for the established reaction with increasing the concentration of atmospheric H₂O, accompanied by the partially compensating decrease in the pre-exponential factor.     

CZE separation of amitrol and triazine herbicides in environmental water samples with acid-assisted on-column preconcentration

A simple analytical scheme for the detection and quantification of amitrol and triazine herbicides (atrazine, ametryn and atraton) and degradation product (2‐hydroxyatrazine) in environmental water samples by CZE is reported. On‐column preconcentration of analytes from untreated water samples (mineral, spring, tap and river water) is accomplished by introducing an acid plug (200 mM citrate of pH 2.0) after the sample and then proceeding with the CZE separation, using 100 mM formiate buffer of pH 3.5 as running buffer and 25.0 KV as separation voltage. UV detection at 200 nm provides LODs from 50 to 300 nM in untreated samples and they were lowered tenfold by sample preconcentration by evaporation. Calculated recoveries were typically higher than 90%. Minimal detectable concentration of the electroactive amitrol could be decreased about 20‐fold when electrochemical detection was employed by monitoring the amperometric signal at +800 mV using a carbon paste electrode (LOD of 9.6 nM, 0.81 μg/L, versus 170 nM, 14.3 μg/L, using amperometric and UV detection, respectively) in untreated water samples.     

Analogy between real irreducible tensor operator and molecular two-particle operator

. Molecular matrix elements of a physical operator are expanded in terms of polycentric matrix elements in the atomic basis by multiplying each by a geometrical factor. The number of terms in the expansion can be minimized by using molecular symmetry. We have shown that irreducible tensor operators can be used to imitate the actual physical operators. The matrix elements of irreducible tensor operators are easily computed by choosing rational irreducible tensor operators and irreducible bases. A set of geometrical factors generated from the expansion of the matrix elements of irreducible tensor operator can be transferred to the expansion of the matrix elements of the physical operator to compute the molecular matrix elements of the physical operator. Two scalar product operators are employed to simulate molecular two-particle operators. Thus two equivalent approaches to generating the geometrical factors are provided, where real irreducible tensor sets with real bases are used. Received: 3 September 1996 / Accepted: 19 December 1996     

微溶剂萃取-气相色谱-质谱法测定水中邻苯二甲酸二(2-乙基己基)酯

取水样25mL,加入无水硫酸钠3.0g,加入环己烷2.0mL,振荡萃取3min。移取萃取了邻苯二甲酸二(2-乙基己基)酯(DEHP)的上层有机相2.0μL注入HP-5毛细管柱(30m×0.32mm,0.25μm)色谱分离后进行质谱测定。DEHP的质量浓度在50.0μg.L-1以内与其峰面积呈线性关系,方法的检出限(3S/N)为0.052μg.L-1。分析了早、中、晚不同时间的天津市自来水,并用标准加入法做回收试验,测得回收率在97.0%～109.4%之间,测定值的相对标准偏差(n=6)均小于2.5%。     

薄层色谱自动点样仪的研制

介绍了一种由单片机系统控制的薄层色谱自动点样装置,其中喷嘴和机械部分的制作比较实用。采用本文设计,能制出足以与商品仪器媲美的产品,且成本极低。     

小量水样痕量苯酚的液-液微萃取气相色谱分析

 建立了小量水样痕量苯酚的液 液微萃取气相色谱分析法。考查了乙酸乙酯在酸和盐的作用下对苯酚的萃取性能 ,优化了萃取过程。采用FID检测器、WBI 17直接进样口和DB 1宽口径弹性石英毛细管柱 ,通过快速进样和汽化室内填装适当的玻璃棉可以得到满意的定量精密度。 8mL水样、16 0 μL乙酸乙酯、3 5 g硫酸铵可获得 1μg/L的检测下限 ,加标回收率为 95 0 %～ 98 5 % ,RSD为 2 8%～ 3 3%。     

冠醚富集原子吸收光谱法测定水样中痕量镉

报道了用装有涂布了聚苯并15－冠－5（A型）的分子筛的玻璃分离柱可用于水中痕量镉的预富集,此分离方法是基于CdI4^2-络阴离子与冠醚的络合反应,取水样750ml调其酸度至pH3左右,加入KI 15g,溶解后,以2－3ml.min^-1的流速通过交换柱,用0．5mol.L^-1 HCl作为洗脱剂,以0．3－0．5ml.min^-1的流速将Cd^2 从络合物中解脱淋洗下,淋也液定容为25ml后用FAAS法测定其含镉量。