TY - JOUR
T1 - The influence of the thin-layer flow cell design on the mass spectra when coupling electrochemistry to electrospray ionisation mass spectrometry
AU - Zettersten, Camilla
AU - Lomoth, Reiner
AU - Hammarström, Leif
AU - Sjöberg, Per J.R.
AU - Nyholm, Leif
N1 - Funding Information:
Financial support from The Swedish Research Council (grant no. 621-2003-3626 and 621-2001-3139), The Swedish Foundation for Strategic Research (SSF), MedChip, The Swedish Energy Agency and The Royal Swedish Academy of Sciences is gratefully acknowledged. Magnus Anderlund and Professor Licheng Sun (Stockholm University, Sweden) are acknowledged for kindly providing samples of the compound. The authors also want to thank Andreas Dahlin for help with the preparation of Fig. 1 .
PY - 2006/5/1
Y1 - 2006/5/1
N2 - The influence of the flow cell configuration on the mass spectra obtained when coupling an electrochemical thin-layer flow cell to electrospray mass spectrometry (ESI-MS) has been investigated. It is shown that interferences due to the electrochemical reaction on the counter electrode and/or the absence of 100% conversion efficiency can alter the mass spectra when conventional thin-layer flow cells are used in conjunction with ESI-MS. The effects, which affect the intensities and distribution of the peaks in the mass spectra, can result in the inability to detect products formed at the working electrode. Comparisons of mass spectra, generated after the electrochemical oxidation of a dinuclear Mn complex [ Mn2II, II ( bpmp ) ( μ - OAc )2 ]+ (where bpmp = 2,6-bis[bis(2-pyridylmethyl) amino]methyl-4-methylphenol) using two different thin-layer flow cells clearly show that the potential dependence and appearance of the mass spectra depend on the flow cell configuration used. The use of a modified thin-layer flow cell, in which the counter electrode had been separated from the working electrode, gave rise to significantly increased intensities for the oxidised MnIII,IV state of the complex. With the conventional unmodified cell, the corresponding complex was only seen for considerably higher oxidation potentials. The different results can be explained by the reduced risk of redox cycling and interferences due to species generated at the counter electrode with the modified cell. As interferences due to the counter electrode reactions likewise may be expected with many coulometric flow cells, the electrochemical cell design clearly needs to be considered when using electrochemistry coupled to ESI-MS to study electrochemical reactions.
AB - The influence of the flow cell configuration on the mass spectra obtained when coupling an electrochemical thin-layer flow cell to electrospray mass spectrometry (ESI-MS) has been investigated. It is shown that interferences due to the electrochemical reaction on the counter electrode and/or the absence of 100% conversion efficiency can alter the mass spectra when conventional thin-layer flow cells are used in conjunction with ESI-MS. The effects, which affect the intensities and distribution of the peaks in the mass spectra, can result in the inability to detect products formed at the working electrode. Comparisons of mass spectra, generated after the electrochemical oxidation of a dinuclear Mn complex [ Mn2II, II ( bpmp ) ( μ - OAc )2 ]+ (where bpmp = 2,6-bis[bis(2-pyridylmethyl) amino]methyl-4-methylphenol) using two different thin-layer flow cells clearly show that the potential dependence and appearance of the mass spectra depend on the flow cell configuration used. The use of a modified thin-layer flow cell, in which the counter electrode had been separated from the working electrode, gave rise to significantly increased intensities for the oxidised MnIII,IV state of the complex. With the conventional unmodified cell, the corresponding complex was only seen for considerably higher oxidation potentials. The different results can be explained by the reduced risk of redox cycling and interferences due to species generated at the counter electrode with the modified cell. As interferences due to the counter electrode reactions likewise may be expected with many coulometric flow cells, the electrochemical cell design clearly needs to be considered when using electrochemistry coupled to ESI-MS to study electrochemical reactions.
KW - Binuclear manganese complexes
KW - Electrochemistry
KW - Electrospray ionisation mass spectrometry
KW - Flow cell design
KW - Oxidation
KW - Thin-layer cells
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U2 - 10.1016/j.jelechem.2006.02.028
DO - 10.1016/j.jelechem.2006.02.028
M3 - Article
AN - SCOPUS:33646245679
VL - 590
SP - 90
EP - 99
JO - Journal of Electroanalytical Chemistry
JF - Journal of Electroanalytical Chemistry
SN - 1572-6657
IS - 1
ER -