A robust method for speciation, separation and photometric characterization of all [PtCl6-nBrn]2- (n=0-6) and [PtCl4-nBrn]2- (n=0-4) complex anions by means of ion-pairing RP-HPLC coupled to ICP-MS/OES, validated by high resolution 195Pt NMR spectroscopy
Date
2011
Authors
van Wyk P.-H.
Gerber W.J.
Koch K.R.
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Abstract
A robust reversed phase ion-pairing RP-HPLC method has been developed for the unambiguous speciation and quantification of all possible homoleptic and heteroleptic octahedral platinumIV [PtCl6-nBrn]2- (n=0-6) as well as the corresponding platinumII [PtCl4-nBrn]2- (n=0-4) complex anions using UV/Vis detection. High resolution 195Pt NMR in more concentrated solutions of these PtII/IV complexes (≥50mM) served to validate the chromatographic peak assignments, particularly in the case of the possible stereoisomers of PtII/IV complex anions. By means of IP-RP-HPLC coupled to ICP-MS or ICP-OES it is possible to accurately determine the relative concentrations of all possible PtII/IV species in these solutions, which allows for the accurate determination of the photometric characteristics (λmax and e{open}) of all the species in this series, by recording of the UV/Vis absorption spectra of all eluted species, using photo-diode array, and quantification with ICP-MS or ICP-OES. With this method it is readily possible to separate and estimate the concentrations of the various stereoisomers which are present in these solutions at sub-millimolar concentrations, such as cis- and trans-[PtCl4Br2]2-, fac- and mer-[PtCl3Br3]2- and cis- and trans-[PtCl2Br4]2- for PtIV, and cis- and trans-[PtCl2Br2]2- in the case of PtII. All mixed halide PtII and PtIV species can be separated and quantified in a single IP-RP-HPLC experiment, using the newly obtained photometric molar absorptivities, e{open}, determined herein at given wavelengths. © 2011 Elsevier B.V.
Description
Keywords
platinum complex, platinum derivative, article, elution, ion pair extraction, mass spectrometry, nuclear magnetic resonance spectroscopy, optical emission spectroscopy, photometry, priority journal, proton nuclear magnetic resonance, reversed phase high performance liquid chromatography, separation technique, spectral sensitivity, spectroscopy, stereoisomerism, ultraviolet spectroscopy
Citation
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