Muhammad Umar Mian2025-12-032025-12-032019https://escholar.umt.edu.pk/handle/123456789/15038The most toxic element arsenic is found in different oxidation states in environment and has serious health concerns about humans. The contamination by arsenic is both by natural and anthropogenic processes. The currently employed methods for the detection and quantification of arsenic are costly, sophisticated and time consuming. But image scanning densitometry (ISD) method is appropriate for on-site analysis. It is based on the generation of arsine by the reduction of arsenite by sodium borohydride in a specific reaction assembly. Arsine gas is passed through the filter paper which is impregnated with mercuric bromide. A color spot appears which is scanned and the color intensity of the spot is measured by image scanning densitometer (ISD) or optical raw density (ORD). The result of this method is compared with conventional reflectance spectrophotometer. This technique is effective and reliable for detection of arsenic at trace level amount having linear response at the concentration range of 2 to 20 ppb or (2-20 μg /L). The detection limit of arsenic has found to be 0.733 ppb. The results of ISD method are reliable and comparable with sophisticated method e.g. Vis-spectrophotometry, Gas chromatography and High performance liquid chromatography (HPLC). This method requires only 1μL of analyte or reagent for spot development. The result of this technique is followed by hydride generation atomic absorption spectrometry (HG-AAS).enThesis