Iodine is an essential trace element for human health, but excessive or insufficient intake can cause thyroid disorders. Iodine can also be introduced into water as a disinfectant or a disinfection by-product. Therefore, iodine analysis is important to monitor the quality and safety of drinking water. GB/T-5750.5 Standard Examination Methods for Drinking Water - Part 5: Inorganic Anions and Inorganic Non-Metals specifies the methods for determining the concentrations of inorganic anions and inorganic non-metals in drinking water, such as fluoride, chloride, nitrite, nitrate, sulfate, phosphate, bromate, iodate, chlorite, chlorate, bromide, iodide, cyanide, sulfide, and silicate. Section 13.4 outlines the analytical procedures for the measurement of iodine in drinking water using inductively coupled plasma mass spectrometry (ICP-MS).
In comparison to other analytical techniques, ICP-MS has the advantages of multi-element detection, low detection limits, high speed of analysis, wide dynamic range, etc. However, it is affected by plasma and matrix-based polyatomic interferences and doubly charged species, which need to be accounted for by applying mathematical corrections and/or using collision/reaction mechanisms. The NexION® 1100 ICP-MS, equipped with Universal Cell Technology (UCT), can be operated in both Collision mode with kinetic energy discrimination (KED) and Reaction mode with dynamic reaction cell (DRC) to tackle polyatomic interferences.
This work demonstrates the ability of the NexION® 1100 ICP-MS to meet and/or exceed the specifications recommended by GB/T-5750.5-2023 for the measurement of iodine in drinking water.