Method 245.1

This method describes the instrumental analytical procedures for mercury by cold vapor atomic absorption (CVAA). This method is applicable for drinking, ground, surface, sea and brackish water, domestic and industrial wastes. 

This method applies to the determination of total mercury (organic + inorganic) by Method 245.1. Sample and standard preparation procedures are described in SOP 415.  The reporting limit (RL) is 0.2 micrograms/liter (parts per billion, ppb) for total mercury.  An aliquot of a water sample is transferred to a BOD bottle or equivalent closed-system container. The sample is digested with a dilute potassium permanganate-potassium persulfate solution for two hours at 95 degrees centigrade. The digestion oxidizes all forms of mercury to Hg (II). The Hg (II) in the digested water sample is reduced with stannous chloride to elemental mercury which is sparged from the sample and detected by atomic absorption. The measurement step is performed using an automated mercury analyzer.

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