Spectrophotometric Determination of Chromium in Water, and Pharmaceutical Samples Using 1-Naphthol

K Suvardhan,K Suresh Kumar,B S Sastry,D Rekha,Umayur Bhagan,G R K Naidu,P Chiranjeevi,S Ramanaiah,G Krishnamurthy Naidu

doi:10.1155/2005/140534

Abstract

Facile and sensitive spectrophotometric methods for the determination of trace and ultra trace amounts of chromium (VI) are described. 4-aminoantipyrine (APP) reacts with 1-naphthol (NPL) in presence of oxidising agent potassium dichromate in acidic medium to produce red coloured product having λmaxof 485 nm. The molar absorptivity and Sandell's sensitivity were 2.07x104l mol-1cm-1and 0.00240 μg/cm2respectively. The colour is stable for more than 6 h. The system obeys Beer's law in the range, 2-18 μg for determination of chromium (VI). The detection limits of chromium (VI) is 0.048 μg mL-1. The method is highly reproducible and has been applied to the analysis of chromium in synthetic, natural water samples and pharmaceutical preparations and the results compared favourably with the reported method.

Highlights

The determination of trace amounts of chromium in soils and other naturally occurring materials is of considerable interest, because of the contrasting biological effects of its two common oxidation states, chromium (III) and chromium (VI) and the growing interest in environmental problems
It is known that an increase in the concentration of chromium in soils makes them infertile and that the toxic effect depends to some extent on the chromium Oxidation State
Other reagents have been suggested for spectrophotometric determination of chromium with the use of 4(2-pyridylazo) resorcinol 12, phenylarsenazo[13], and gallacetophenone oxime[14], citrazinic acid[15]

Summary

Introduction

The determination of trace amounts of chromium in soils and other naturally occurring materials is of considerable interest, because of the contrasting biological effects of its two common oxidation states, chromium (III) and chromium (VI) and the growing interest in environmental problems. It is known that an increase in the concentration of chromium in soils makes them infertile and that the toxic effect depends to some extent on the chromium Oxidation State. The determination of chromium by spectrophotometric methods based on oxidation of organic compounds[4,5,6] and on formation ion associates[1,7] has the disadvantage of a high blank value. The above reported methods suffer from several drawbacks like less sensitive, low detection limits, high reagent consumption and instability of resultant product. Development of a simple, rapid and sensitive spectrophotometric method is highly desirable

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