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Adduct simplification in the analysis of cyanobacterial toxins by matrix‐assisted laser desorption/ionization mass spectrometry
Author(s) -
Howard Karen L.,
Boyer Gregory L.
Publication year - 2007
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2887
Subject(s) - chemistry , adduct , mass spectrometry , desorption , lithium chloride , chromatography , chloride , inorganic chemistry , matrix assisted laser desorption/ionization , zinc , adsorption , organic chemistry
A novel method for simplifying adduct patterns to improve the detection and identification of peptide toxins using matrix‐assisted laser desorption/ionization (MALDI) time‐of‐flight (TOF) mass spectrometry is presented. Addition of 200 µM zinc sulfate heptahydrate (ZnSO 4 · 7H 2 O) to samples prior to spotting on the target enhances detection of the protonated molecule while suppressing competing adducts. This produces a highly simplified spectrum with the potential to enhance quantitative analysis, particularly for complex samples. The resulting improvement in total signal strength and reduction in the coefficient of variation (from 31.1% to 5.2% for microcystin‐LR) further enhance the potential for sensitive and accurate quantitation. Other potential additives tested, including 18‐crown‐6 ether, alkali metal salts (lithium chloride, sodium chloride, potassium chloride), and other transition metal salts (silver chloride, silver nitrate, copper(II) nitrate, copper(II) sulfate, zinc acetate), were unable to achieve comparable results. Application of this technique to the analysis of several microcystins, potent peptide hepatotoxins from cyanobacteria, is illustrated. Copyright © 2007 John Wiley & Sons, Ltd.