Development and validation of a simple spectrophotometric method for quantification of chloride in polymeric materials

Abstract

A simple analytical method was developed for determination of chloride content in polymeric materials. The procedure comprises of two steps, the dissolution of the polymer by alkaline fusion followed by indirect spectrophotometric analysis of the chloride based on the absorption at 460 nm of Fe(SCN)²⁺, a product of the reaction between chloride ion and a mixture of mercury (II) thiocyante and ferric ion. A non-linear calibration curve was constructed from 0.5 to 20 ppm with R² = 0.9991; the limit of detection and quantitation were of  0.325 and 1.083 ppm, respectively. The recovery of the whole procedure was higher than
92.9 % with a RSD ~ 2.4 %. The developed procedure was applied to animated poly(divinylbenzene‑co‑vinyl benzyl chloride) in order to investigate the extent of amination of the base material.