Mercury AAS with cold vapour method

1 Mercury AAS with cold vapour method Principle of the method 

Mercury ions are reduced to metallic mercury with tin(II) chloride. The metallic mercury is transferred into a quartz cuvette with the aid of a current of inert gas and the absorption of the atoms is measured in the beam of an atomic-absorption spectrometer (cold vapour method). 

Treat 300 ml of nitric acid (1.40 g/ml) with 3 g potassium dichromate (K2Cr207) and make up to 1000 ml with water. 

Treat 10 g tin (II) chloride (SnCl2 2 H2O) with 10 ml hydrochloric acid (1.17 g/ml) and make up to 100 ml with water, shaking constantly. 

Immediately after sampling add 1 ml of the stabilizing reagent per 100 mi of sample volume to the water samples in order to prevent losses by absorption of mercury at the vessel walls. 

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