On‐Site Determination of Arsenic in Contaminated Water^#

^#Accepted for poster presentation in IMA conference to held in Thessaloniki, Greece, 23–27 Sept., 2003.

ABSTRACT

A new spectrophotometric method for the on‐site determination of arsenic in contaminated water samples has been developed. The method is simple, rapid, and selective. It is based on reduction of As(V) to As(III) with ascorbic acid, complexation of As(III) with I⁻ ions in strong HCl medium and extraction of the yellow colored iodo‐complex with N‐octylacetamide into chloroform solution. The optimum acidity range is 4.5–6.0 M HCl/2.5–3.5 M H₂SO₄. The apparent value (i.e., at two fold enrichment factor) of molar absorptivity in the term of arsenic is (5.00) × 10⁴ L mol⁻¹ cm⁻¹ at λ_max, 420 nm. The detection limit (i.e., absorbance causing more absorbance than 3s) of the method is 10 µg L⁻¹ As. The method is free from interference of the ions commonly found to be associated with arsenic in environmental samples. The method has been tested for the field determination of arsenic in contaminated waters (i.e., surface, ground, rice field) of central India.

^#Accepted for poster presentation in IMA conference to held in Thessaloniki, Greece, 23–27 Sept., 2003.

Keywords:

• Arsenic
• Spectrophotometric determination
• Iodo‐complex
• N‐Octylacetamide

ACKNOWLEDGMENTS

We are heartily thankful to CSIR, New Delhi for the financial support in the form of the project. Our sincere thanks are extended to the Alexander von Humboldt Foundation, Bonn for granting fellowship to KSP for paper writing in ISAS, Dortmund. We also acknowledge Dr. N. Jakubowski and his co‐workers, ISAS, Dortmund, Germany for the thorough and constructive review of the manuscript for improvement.

Notes

^#Accepted for poster presentation in IMA conference to held in Thessaloniki, Greece, 23–27 Sept., 2003.

^aCausing error <±2%.

Note: WW, well water; TWW, tube‐well water; PW, pond water; RW, river water; RFW, rice field water.

^aFour analysis were carried out.