Method for detecting metal ions in aqueous solution based on refractive index change rate

The invention relates to a method for detecting metal ions in an aqueous solution based on the refractive index change rate, and belongs to the heavy metal detection technology. The method comprises the following steps: (1) drawing a refractive index-salt concentration curve of a plurality of metal salt standard solutions to obtain refractive index change rate Deltan of each metal salt solution, namely a series of Deltan corresponding to the plurality of metal salt standard solutions; (2) taking a to-be-detected aqueous solution sample, and detecting the content of soluble substances by taking g/L as a unit; and (3) drawing a refractive index-salt concentration curve of a to-be-detected aqueous solution sample to obtain a refractive index change rate Deltan(s) of the to-be-detected sample; and (4) matching the Deltan(s) with a series of Deltan obtained in the step (1), so that the matched metal types in the metal salt standard solution are the metal types in the to-be-detected aqueous solution sample, and qua