Then dissolve the iron hydroxide with dilute aqua regia to oxidize iron ions completely into a trivalent state,which will react with ammonium rhodanate to form a dark red coordination compound-ferric rhodanate,by which a colorimetric assay can be conducted.

Method improvement of arsenic in soils extracted using aqua regia by HG-AFS;

Study on extracting Pb,Cr,Cd,As from soil samples by aqua regia in boiling bath;

Samples are fused with chlorazotic acid, then, SnCl 2 reduced, Hg absorption peak value is determined under optimum instrument conditions.

The samples are decomposed by aqua regia,that is,adding some molysite in 10% aqua regia solution,the Au in the samples will be absorbed by the polyaminoester foamed plastics.

The method of VG-AFS with clearing by aqua regia to determine As、Sb and Hg in the soil;