Spectrochemical Determination of Metallic Pollutants At Sub Ppm Levels In Fresh Water Samples

Abstract

A quantitative method to analyse fresh water samples for ultratrace pollutants such as Cd, Cr, Fe, Mn, Ni, Pb, V and Zn has been developed. the impurities in the water sample were preconcentrated by the method of slow evaporation and collected on specpure graphite which was subsequently analysed by d.c. are excitation using NaF as the carrier. the mean relative standard deviation of the method employed is + 15%. the accuracy of the method reported has been found to be quite satisfactory as borne out by the results of the Intercomparison Run conducted by the International Atomic Energy Agency, Vienna for the determination of trace elements in water. the detection limits for the various elements are as follows: Ni, Pb, V : 1 ng/ml; Cd, Cr, Mn: 2 ng/ml; Fe: 15 ng/ml and Zn : 20 ng/ml. Some of these detection limits have been compared with those obtained in some of the recent techniques such as AAS, Laser Induced Fluorescence (LIF) and Laser Enhanced Ionization (LEI) or Opto-Galvanic Spectrometry(òGS). It has been found that there is a tenfold increase in sensitivity for Pb in the present method as compared to the above techniques except LEI while the detection limits obtained for other elements are comparable with those in other techniques.

Key Words:

• Emission Spectroscopy
• Environmental Assessment Impurities in water