摘要:

A simple and inexpensive method for determining chromium (VI) in drinking water by spectrophotometry after preconcentration with sodium dodecyl sulphate (SDS) coated alumina column is described. Chromium(VI) is reacted with diphenylcarbazide (DPC) and the Cr-DPC complex is quantitatively adsorbed onto a SDS coated alumina column from 800 ml of sample solution. The complex is then eluted with a 8 ml mixture of methanol, acetone and hydrochloric acid and determined by spectrophotometry. Total chromium can be determined after oxidation of chromium (III) to chromium (VI) by KMnO4. The relative standard deviation (10 replicate analyses) at the 10 μg l−1of chromium (VI) and 10 μg l−1of total chromium were 3.5% and 3.4% and corresponding limits of detection (based on 3 σ) were 0.040 μg l−1and 0.033 μg l−1, respectively.

ISSN:0003-2719    

DOI:10.1080/00032719608000807

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A flow injection kinetic method has been developed for the determination of nitrite, based on its catalytic effect on bromate oxidation of chlorophosphonazo-pN in H2SO4medium. The reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 551 nm. The sampling frequency was 83 h−1. The calibration curve was linear between 0.050 and 1.00 μg/ml, and the detection limit was 0.018 μg/ml. The proposed method was applied to the determination of nitrite in waters and soil with satisfactory results.

ISSN:0003-2719    

DOI:10.1080/00032719608000808

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A novel method was developed for separation and determination of D-gluconic acid produced during fermentation by capillary zone electrophoresis (CZE) with direct UV detection at 214 nm, using selected carrier electrolyte composed of 6 mM potassium biphthalate, 50 mM disodium hydrogen phosphate and 15% (v/v) acetonitrile. The effects of concentration of phthalate, phosphate and organic modifier (acetonitrile), as well as temperature for the separation were investigated. The method is simple, inexpensive and will make it very useful in the gluconic acid industry.

ISSN:0003-2719    

DOI:10.1080/00032719608000809

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper discusses the requirements and scope of application of the H-point Standard Additions Method (HPSAM) when the matrix effect is absent. It is demonstrated that the HPSAM calibration method works well with slopes of calibration graphs as standards. It is applied to the resolution of binary mixtures of intact and acid degraded cephalosporins. The results obtained are better than those obtained by second derivative spectrophotometry.

ISSN:0003-2719    

DOI:10.1080/00032719608000810

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A method for quantitative analysis of multicomponent mixtures with unknown individual spectra of the components, based on resolution of overlapping bands, is developed and its reliability is illustrated in analysis of both model and real mixtures. The two-step optimization procedure allows attainment of high precision, the molar parts and the individual spectra of the components. This approach could be used in molecular spectroscopy (UV-Vis-NIR, IR, Raman and CD spectroscopy) as well as in chromatography.

ISSN:0003-2719    

DOI:10.1080/00032719608000811

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719608000814

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor