A group of Chinese researchers has developed a rapid method for determining monoiodoacetic acid and inorganic iodine in drinking water by combining capillary electrophoresis and inductively coupled plasma mass spectrometry (CE-ICP-MS).
Background: Chemical disinfection of drinking water using ozone, chlorine, or chloramine is a common practice worldwide. Disinfectants react with natural organic matter, anthropogenic pollutants, and iodides to produce iodinated disinfection by-products such as iodoacetic acids (IAAs).
Figure: iodoacetic acid
|
While the concentration of IAAs is generally lower
than that of other haloacetic acids, IAAs exhibit higher cytotoxicity
and genotoxicity. The health risks associated with these compounds have
led to legislative restrictions and the need for appropriate analytical
methods for testing.
Existing methods based on gas chromatography require complex and time-consuming derivatization. Liquid chromatography, whether ion-chromatography (IC) or high-performance liquid chromatography (HPLC), is often time-consuming and necessitates coupling with sensitive mass spectrometry for detection.
The New Study:The researchers propose using the combination of capillary electrophoresis (CE) and inductively coupled plasma mass spectrometry (ICP-MS) to determine three forms of iodine: I⁻, IO₃⁻, and MIAA in drinking water. The rapid and highly selective CE-ICP-MS technique does not require complex sample pretreatment steps or the use of organic reagents. Optimum separation of the three species was achieved in less than 10 minutes using a 10 mM Tris-HCl buffer solution at pH 8.5. Under these conditions, detection limits of 0.16 µg/L for KI, 0.40 µg/L for KIO₃, and 1.22 µg/L for MIAA were obtained.
While the detection limits are lower than those reported for LC-ICP-MS, they are sufficient to meet water quality standards. The accuracy of the method was tested by spiking 10 µg/L of each species into different water samples. The recoveries ranged from 85.5% to 96.8%, confirming the method's accuracy.
The original publication
Yuke Wu, Xi Wang, Zhengqin Pang, Jinyi Zhang, Chengbin Zheng,
Rapid and simultaneous analysis of monoiodoacetic acid and inorganic iodine in drinking water by capillary electrophoresis-inductively coupled plasma mass spectrometry, Microchem. J., 203 (2024) 110809.
DOI: 10.1016/j.microc.2024.110809 Related Studies (newest first):
D. Liu, S. Cheng, W. Ji, H. Shen, J. Yuan, J. Wang, W. Zhang, H. Liu, Y. Zhou,
Determination and generating study on monoiodoacetic acid and diiodoacetic acid in water by liquid chromatography inductively coupled plasma mass spec trometry, Microchem. J., 159 (2020) 105401.
DOI: 10.1016/j.microc.2020.105401 J.-J. Xu, Y.X. Chang, J. Hao, M. An, Z. Tan, R. Yang, J. Cao, L.Q. Peng,
Separation and stacking of iodine species from seafood using surfactant coated multiwalled carbon nanotubes as a pseudo stationary phase in capillary electrophoresis, Microchim. Acta, 183 (2016) 2441 2447.
DOI: 10.1007/s00604-016-1892-6 J. Sun, D. Wang, H. Cheng, J. Liu, Y. Wang, Z. Xu,
Use of ion pairing reagent for improving iodine speciation analysis in seaweed by pressure driven capillary electrophoresis and ultraviolet detection, J. Chromatogr. A, 1379 (2015) 112 117.
DOI: 10.1016/j.chroma.2014.12.056 H. Zhang, J. Zhu, R. Aranda-Rodriguez, Y.-L. Feng,
Pressure-assisted electrokinetic injection for on-line enrichment in capillary electrophoresis–mass spectrometry: A sensitive method for measurement of ten haloacetic acids in drinking water, Anal. Chim. Acta, 706 (2011) 176–183.
DOI: 10.1016/j.aca.2011.07.040 B.P.Y. Lau, A. Becalski,
Determination of iodoacetic acid using liquid chromatography/electrospray tandem mass spectrometry, Rapid Comm. Mass Spectrom., 22/12 (2008) 1787-1791.
DOI: 10.1002/rcm.3547
J.H. Chen, K.E. Wang, S.J. Jiang,
Determination of iodine and bromine compounds in foodstuffs by CE inductively coupled plasma MS, Electrophoresis, 28 (2007) 4227- 4232.
DOI: 10.1002/elps.200700241 Z. Huang, K. Ito, A.R. Timerbaev, T. Hirokawa,
Speciation studies by capillary electrophoresis simultaneous determination of iodide and iodate in seawater, Anal. Bioanal. Chem., 378 (2004) 1836-1841.
DOI: 10.1007/s00216-004-2506-4
last time modified: June 12, 2024
