Nitric oxide during adsorption

The determination of an inorganic element in an organic matrix usually requires a preliminary treatment to remove the organic matter completely, either by dry-ashing or by oxidation with acids such as nitric, sulfuric or perchloric. Then, the problem reverts to the determination of an inorganic analyte in an inorganic matrix, as above. You should be aware that losses of trace elements can occur during such oxidation processes, either by volatilization or by adsorption onto the surface of the equipment used. 

To reduce losses by adsorption and evaporation of dissolved gaseous mercury (DGM) from solution during storage, the sample should be kept strongly acidified (pH l), preferably with an oxidizing mineral acid such as nitric acid. 

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