Complementary matrix-assisted laser desorption/ionization and inductively coupled plasma mass spectrometry detection of single separation record
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| Year of publication | 2013 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | The analyses of native metal-protein and metal-metabolite complexes by hyphenated techniques that combine separation with a specific detection is of growing importance. Using a liquid junction, capillary electrophoresis (CE) was coupled in the off-line mode to both matrix-assisted laser desorption/ionization mass spectrometry (MALDI) and substrate-assisted laser desorption inductively-coupled plasma (SALD ICP) mass spectrometry (MS). Here we present a new approach for an off-line multidetection platform for metalloprotein/metallopeptide analysis of fractions collected from a single CE run. CE fractions are collected on a special target and analyzed consecutively with MALDI MS and SALD ICP MS. The concept is demonstrated on the CE-MALDI/SALD ICP MS analysis of rabbit liver metallothionein (MT) isoforms: The mixture of MT isoforms was separated in uncoated fused silica capillary (70 cm, 75um) using 20 mM ammonium bicarbonate buffer, pH 7.4 as background electrolyte. Fractions from CE were collected on polyethyleneglycol target with a thin golden layer in a subatmospheric deposition chamber. After matrix addition, MALDI mass spectra of MT apoforms were recorded from the fractions. Finally, SALD ICP provided information on Cd content in the fractions. Alternatively, MALDI mass spectra of un dissociated MT complexes from selected fractions may be recorded using a colder MALDI matrix. In summary, it was shown that a single CE separation yielded both proteomic and metallomic information. The off-line approach is a viable alternative to on-line coupling with electrospray/nebulizer ICP MS and it does not require both mass spectrometers physically close to CE. In addition, the fractions may be archived and subjected to laser-induced fluorescence detection or on target digestion. |
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