摘要:

An alternative, highly selective method for cooper(II) analysis in alcoholic beverages (brandies) is proposed using EPR spectroscopy. The method is simple, non destructive, fast and can be used for concentrations down to 100 ppb, with 1.1% (x= 1.55, s = 0.0179) RSD (relative standard deviation) and 98.7% accuracy.

ISSN:0003-2719    

DOI:10.1080/00032719908542854

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A method for the rapid determination of toxic elements in finger paints based on the microwave sample digestion followed by the atomic spectrometric detection has been evaluated. The detection techniques used were Inductively Coupled Plasma Atomic Emission Spectrometry (ICPAES) for Ba, Cd, Cr and Pb, Cold Vapour Atomic Absorption Spectrometry (CVAAS) for Hg and Hydride Generation Atomic Absorption Spectrometry (HGAAS) for As, Sb and Se. The results obtained indicated that the proposed method was suitable to determine toxic elements in finger paints at concentration levels below the maximum allowed by the European Standard EN 71 Safety of toys.

ISSN:0003-2719    

DOI:10.1080/00032719908542855

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper describes a reversed flow injection spectrophotometric method for determination of manganese(II) at low levels. A new chromogenic system TCMOPPH2-Cd(II)-imidazole has been set up using a novel synthetic chromogenic reagent meso-tetra[4-(carboxymethylenoxy)phenyl]porphyrin [TCMOPPH2] by a substitution reaction of Mn(II) and Cd(II)-TCMOPP complex. The linear range extends from 0.01 to 1.75mg.L−1with a sampling frequency of 90 h−1. Co(II), Cu(II), Cr(III) and Fe(II) exert no interference until their concentrations are up to 30, 32, 15 and 23 times of that of Mn(II), respectively. The proposed method is proved to be simple, sensitive and suitable for on-line determination of Mn(II), and it has been used in analysis of Mn(II) in water samples of Liaohe Oil Field water treat plant during the on spot purification. The detection limit was 2.8μg.L−1.

ISSN:0003-2719    

DOI:10.1080/00032719908542856

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A novel spectrophotometric method based on amino G acid chlorophosphonazo (AGCPA) has been developed for measuring calcium in human serum and cerebrospinal fluids. The effects of experimental factors including pH, reagent concentrations, and interfering species on calcium determinations were investigated. In a neutral reaction media of pH 7.0, AGCPA reacts rapidly with calcium to form a stable and greenish blue complex, whose absorption maximum is at 670 nm. The molar absorptivity (ɛ) of the complex is 7.2x1041 mol−1cm−1, and the molar ratio of calcium to AGCPA in the complex is found to be 1:2. Beer's law is obeyed over the range 0.02-0.8 μg ml−1of calcium. No interferences were observed from the commonly coexisting species present in serum and cerebrospinal fluids. Compared to the reported and currently often used methods based ono-cresolphthalein complexone, arsenazo III and methylthymol blue, the proposed method in this work provides better analytical characteristics such as high sensitivity, good selectivity and neutral reaction media. In addition, the present method is simple and can be applied to the direct determination of calcium in human serum and cerebrospinal fluid samples with satisfactory results.

ISSN:0003-2719    

DOI:10.1080/00032719908542857

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The interference of triglycerides in the analysis of sterols and their esters in fats can be eliminated by transesterification of the sample dissolved in n-hexane with a solution of sodium hydroxide 2 mol/L. Since the analytes are distributed equally in n-hexane and in methanol, better results can be obtained by accurate measurements of the volumes, and processing the standards as the samples. Triglycerides and steryl esters are transesterified quantitatively by a solution of sodium hydroxide 2 mol/L using diethyl ether as solvent. At 40°C, ten minutes are sufficient to complete the reaction. The sterols are determined in fats using a mass spectrometer detector, at concentrations as low as 5 mg/Kg. Using FID, it was possible to analyze sterols present in concentrations higher than 100 mg/Kg.

ISSN:0003-2719    

DOI:10.1080/00032719908542858

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This research describes the nature and extent of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) contamination in the soil samples from a waste cable incineration plant. The samples are collected at different places in the nearest and far away points of the soil around the incineration plant. A procedure which is described for the selective separation of 2,3,7,8-TCDD from all other PCDDs and PCDFs fractionated on Alumina Woelm B Super 1 in such a manner that all PCDDs and PCDFs are eluted prior to 2,3,7,8-TCDD. This procedure allows more sensitive quantitative determination of 2,3,7,8-TCDD in the soil samples.

ISSN:0003-2719    

DOI:10.1080/00032719908542859

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor