ABSTRACT
Inductively coupled plasma-mass spectrometry (ICP-MS) and electrospray mass spectrometry (ESI-MS) were used as complementary methods to identify Sn-pentaacetic acid (DTPA) complex formation. ESI-MS was used to initially confirm the formation of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) and their MS spectra suggest these tin complexes were stable in solution. On-column complexation of tin with DTPA and the separation of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) was performed on anion-exchange chromatography with an mobile phase containing 20mM NH4NO3 and 3mM DTPA at pH 6.0, and the subsequent detection of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) was achieved by ICP-MS. Linear plots were obtained in a concentration range of 1.0-1000 µg L(-1) with detection limits ranging from 0.1 to 0.3 µg L(-1). The developed procedure allows the simultaneous determination of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) in less than 5 min with a RSD between 2.1 and 2.7%. The recoveries of [Sn(DTPA)](3-) and [Sn(DTPA)](1-) were found to be 96.8 and 99.4%, respectively, when the sample was spiked with 20 µg L(-1) standard. Finally, the proposed procedure was used for the determination of tin species in contaminated water.
