Open AccessEnhancement of ion intensity in time-of-flight secondary-ionization mass spectrometry
Author(s) -
Anthony J. Nicola,
David C. Muddiman,
David M. Hercules
Publication year - 1996
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/1044-0305(96)00006-2
Subject(s) - chemistry , analytical chemistry (journal) , mass spectrometry , yield (engineering) , secondary ion mass spectrometry , substrate (aquarium) , analyte , polystyrene , sample preparation , evaporation , chromatography , polymer , ion suppression in liquid chromatography–mass spectrometry , ionization , static secondary ion mass spectrometry , solvent , matrix (chemical analysis) , ion , tandem mass spectrometry , organic chemistry , materials science , oceanography , physics , metallurgy , thermodynamics , geology
Enhancement of ion intensity in static secondary-ionization mass spectrometry (SIMS) has been achieved by using a matrix-assisted sample preparation technique. Previous investigations of polymers and biomolecules by SIMS indicated that secondary-ion (SI) yield is dependent on substrate coverage. Recently we discovered a sample preparation technique that enhanced the SI yield of cyclosporin A (CsA) in an allograft patient sample and neat samples of CsA (1202 u) and polystyrene (M w=2650 u). The preparation technique involves deposition of a submonolayer of cocaine hydrochloride (5 µL of a 20-µg/mL MeOH solution) on an etched silver substrate, solvent evaporation, and subsequent deposition of the analyte. This preparation method resulted in ∼300% increase in the SI yield of CsA and polystyrene when deposited from neat solutions. The original discovery was observed when a blood extract that contained CsA was deposited on an etched Ag substrate that had been soaking in a dilute cocaine solution for ∼2 months. In these initial experiments, the SI yield of CsA was enhanced by over 1 order of magnitude.