Rapid determination of Cl− by light-absorption ratio variation approach using Cl−–eosin Y–Ag+ adsorptive precipitation

The adsorptive precipitation between eosin Y (EY) and AgCl colloids at pH 3.73 caused the sensitive color change of the solution. The reaction mechanism between EY and AgCl was analyzed and this reaction was used for determination of Cl− in trace level by the light-absorption radio variation approach.