Simultaneous Separation and Quantification of Iron and Transition Species Using LC-ICP-MS

Using liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS), this work investigates the simultaneous separation and quantification of seven transition metal species (Fe, Mn, Co, Ni, Cu, Zn, and Cd), based on a separation scheme published by Dionex company that used the spectrophotometric method for quantification. The LC-ICP-MS method overcomes the shortcomings of conventional ferrozine approaches of measuring Fe(II) and total Fe by two separate runs and calculating Fe(III) by the difference of two runs. The advantage is particularly evident in that organo-iron species are found to be the predominant iron species in many natural waters, and the difference method cannot measure the concentration of Fe(III) because ferrozine will not complex with organo-iron species. In the work reported here, the LC-ICP-MS method is successfully applied to the separation of dissolved iron species, as well as six other divalent transition metals in tap water, deionized water, river water, hot springs, and groundwater samples.