27 Oct 2017
A Review of Field Test Kits for Detection of Arsenic in Water
Several field test kits are available for estimation of Arsenic in water. All of them work on the principle mentioned in the following paragraph. Depending on the amount of reagents, quality of reagents and method of testing, different test kits shows different levels of accuracy. All the available test kits are semi quantitative and are based on colour comparison with the reference colour chart provided with the kit. The three most accurate test kits which are widely used and available have been reviewed here.
Principle: Inorganic Arsenic compounds in the water sample are converted to Arsine (AsH2) gas by the reaction of Zinc Dust and Tartaric Acid. Ferrous and Nickel salts have been added to accelerate this reaction. The Arsine gas converts Mercuric Bromide on the test strip to mixed Mercury halogens (such as AsH2 HgBr) that appear with a colour change from white to yellow or brown.