间苯二酚黄-CTAB-核酸共振光散射体系的研究及应用

在PH3．1－3．5的柠檬酸－NaOH介质中，核酸（fsDNA，yRNA）与阳离子表面活剂CTAB对阴离子染料间苯二酚黄的共振黄的共振光散射光谱有 协同增强作用，在最佳实验条件下，fsDNA,yRNA的线性范围均为0－4μg/mL，检出限分别为8．1ng/mL和7.2ng/mL。据此建立了一种测定核酸的新方法。     

Determination of PCBs in river sediment samples—proficiency test for selected Polish laboratories

Eighteen Polish laboratories participated in a proficiency test for the determination of PCBs in river sediment. The participants used their in-house method. The aim of the exercise was to obtain information about the state of the art of PCB analysis in environmental samples. Five PCBs (IUPAC nos. 52, 118, 138, 153 and 180) were selected for the test. The relative standard deviation of the analytical results submitted varied from 45 to 65%, with an outlier rate of 7%. The averages of the results for all analytes were in good agreement with reference values.     

南黄海表层沉积物稀土元素分布与物源关系

对南黄海295个表层沉积物样品稀土元素的电感耦合等离子体质谱法分析,结果表明,南黄海表层沉积物稀土元素平均含量为188.39μg.g-1,稀土富集与重矿物有密切关系;稀土元素的球粒陨石配分模式均呈现Eu负异常,模式具负斜率,表明表层沉积物物质主要来源于大陆地壳。从稀土元素地球化学特征的区域变化来看,南黄海东部沉积物来源于朝鲜半岛,西部沉积物来源于黄河和长江物质输入,中部细粒沉积物主要与黄河及长江物质东南、东北扩散有关,东南部为朝鲜半岛及黄河、长江物质共同作用的结果。     

Processing and structure of gallium nitride—gallium oxide platelet nanostructures

Gallium nitride-gallium oxide structures were formed by heat-treating gallium nitride (GaN) powders in several gas environments at temperatures from 400°C to 900°C. The platelet nanostructured particles were examined at several stages of oxidation by microscopic, structural, chemical and optical spectroscopic techniques. Particle morphology, nanophase characterization and photoluminescence data showed that the oxide layers passivate the GaN platelets surfaces and significantly reduce the yellow emission while enhancing near band-edge emission.     

Ion-pair extraction and GC-MS determination of linear alkylbenzene sulphonates in aqueous environmental samples

A GC-MS method was developed for the determination of linear alkylbenzene sulphonates (LAS) and sulphophenylcarboxylic acids (SPC) in aqueous environmental samples. LAS and SPC were isolated from aqueous samples using methylene green (MG) as ion-pair reagent and derivatised with diazomethane for their chromatographic analysis. LAS and SPC were then analysed with GC-MS in EI mode as their methyl esters. The method eliminates positive and negative interferences found by the methylene blue method and considered to be selective and sensitive for the determination of LAS and SPC in aqueous samples. The recovery of LAS was 98% with a relative standard deviation (R.S.D.) of 2.0% and the detection limit obtained from calculations by using GC-MS results based on S/N:3 was lower than 10 ppb. Obtained results revealed that the method can also be employed in the analysis of organic compounds bearing sulphate and sulphonate groups.     

Multivariate optimization of solvent extraction with 1,1,1-trifluoroacetylacetonates for the determination of total and labile Cu and Fe in river surface water by flame atomic absorption spectrometry

A procedure for simultaneous solvent extraction of Cu(II) and Fe(III) from river surface waters as diethyldithiocarbamates (DDC) 1,1,1-trifluoroacetylacetonates into isobutyl methyl ketone (IBMK) has been developed prior to their determination by flame atomic absorption spectrometry. Experimental design approaches were used in order to obtain the best compromise conditions for simultaneous solvent extraction. Variables such as pH, sodium DDC or 1,1,1-trifluoro-2,4-pentanodione (H(TFA)) concentrations, reaction time, IBMK volume and extraction time have been optimized. First, Plackett–Burman designs involving 13 experiments and 2 replicates were used as screening designs to determine which variables were significant. DDC or H(TFA) concentration, as well as pH and IBMK volume were found statistically significant and they were finally optimized by applying a central composite design (15 experiments and 2 replicates). Optimum values for these variables were selected for compromise extraction conditions of Cu(II) and Fe(III) species. An optimum pH of 5.3 was chosen for Cu–H(TFA) and Fe–H(TFA) formation with an optimum H(TFA) concentration of 0.20% (m/v). The optimum IBMK volume for extraction was 8 ml, allowing a pre-concentration factor of 10. A microwave-assisted peroxydisulfate oxidation was used to break down the metal–organic matter complexes in river surface waters in order to assess the total Cu and Fe contents. Applying the experimental design approach, optimum conditions was an irradiation for 5.0 min at a microwave power of 500 W using 0.5 g of ammonium peroxydisulfate. The method was applied to determine total Cu and Fe contents and also labile Cu(II) and Fe(III) contents in several river surface water samples.     

Determination of 2-mercaptobenzothiazole in river water by HPLC

Summary A method is proposed for the determination of 2-mercaptobenzothiazole in river waters using multi-electrode electrochemical detection HPLC. 2-mercaptobenzothiazole determination is unsatisfactory by gas chromatography as it degrades readily on the column. Multielectrode electrochemical detection HPLC combines sensitivity and the ability to screen out other electrochemically active species. The development work leading up to the proposed method is discussed. The method has a limit of detection of 0.798gl^–1 2-mercaptobenzothiazole and a total standard deviation of 2.06gl^–1 2-mercaptobenzothiazole at a concentration of 7.97gl^–1 2-mercaptobenzothiazole in river water.     

系数倍率导数光谱法定量测定纤维上染料

本文介绍了用系数倍率导数光谱法同时测定黄棕色涤纶上的分散黄ＲＧＦＬ，分散棕２ＲＬ，分散红Ｓ－ＢＷＦＬ的配比。这三种染料吸收峰重叠大，用该法可以完全消除彼此的干扰而不用分离，测得三种染料的配比与工艺配方中的比例一致，结果准确，可靠，回收率较好。这个方法操作简便，快速，可用于纵上染料的测定。     

Simultaneous determination of two serine proteinases by hydrophobic interaction chromatography

Summary An LC clean-up procedure based upon a complexation between polycyclic aromatic hydrocarbons (PAHs) and silica with chemically bonded 2,4-dinitroaniline has been combined with GC/MS. The LC pre-separation makes it possible to obtain a relatively clean fraction of PAHs free from alkanes, alkylbenzenes and naphthalenes, PCBs, chlorinated pesticides and many other interfering compounds. This fraction has been analyzed using capillary GC and mass selective detector (MSD). Substantial improvement of the MS spectra of PAHs with three or more fused benzene rings is achieved.