Determination and generating study on monoiodoacetic acid and diiodoacetic acid in water by liquid chromatography-inductively coupled plasma mass spectrometry

Abstract

In this study, we have developed a method to directly detect monoiodoacetic acid (MIAA) and diiodoacetic acid (DIAA) in drinking water using liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS). MIAA and DIAA were qualitatively analyzed based on the retention time and quantitatively measured using the peak area integral. The figures of merit from five independent labs reveal that the LODs of the method were 0.06 ~ 0.22 μg/L for MIAA and 0.04 ~ 0.18 μg/L for DIAA, and the recovery rates were 95% ~ 107% and 94% ~ 103% for MIAA and DIAA, respectively. Concomitant anions such as 200 mg/L of SO42−, NO3−, BrO3−, and F−, 300 mg/L of Cl− and 2.0 mg/L of chlorine or bromine based haloacetic acids (HAAs) could not interfere with this method. Additionally, the results for the quality control samples from five labs were consistent with one another. The verification data from five independent labs proved that the method is accurate and adaptable. Since the method does not use pretreatments or toxic organic reagents, the greenness of the method is guaranteed compared to that of conventional methods. Hence, the method used to detect MIAA and DIAA in drinking water is qualified as a standard method for wide application. Furthermore, the generation study of iodoacetic acids (IAAs) in Cl2 and UV275-Cl2 disinfection systems was performed. The results showed that the amount of IAAs was significantly higher when UV275-Cl2 was used to disinfect the high-iodium water than when only Cl2 was applied, especially in weak acid conditions. This conclusion is of great importance in suggesting how to reduce the potential risk of IAAs when producing drinking water when chlorine or a UV275-Cl2 disinfection process is applied.