A simple equipment and colorimetric method for determination of chloroform in water

Abstract

Chlorination is a common and successful method for disinfection of water all around the world, especially in developing countries. However, this process can produce trihalomethanes (THMs) byproducts which are carcinogen. The major THM occurring in this process is chloroform. The purpose of this study was to design a simple equipment for colorimetric determination of chloroform in various water samples. The method is based on the colorimetric reaction of chloroform with resorcinol in strong basic medium on a filter paper. Response surface methodology (RSM) was employed to optimize the determination condition. The reagents were immobilized on filter paper and the color change was followed to quantify chloroform without using any analytical instrument. Detection limit and linear range of the proposed method were 0.007 mg/L and 0.011–1.192 mg/L, respectively for analysis of samples with volume of 2.0 L. The method was successfully applied to determine chloroform in different water samples and compared with GC-MS as a standard method. Employing the designed device, purge, trap and analysis steps were performed in a single run which can reduce the uncertainties originated by excessive steps of the analysis.