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Signal enhancement of carboxylic acids by inclusion with β‐cyclodextrin in negative high‐voltage‐assisted laser desorption ionization mass spectrometry
Author(s) -
Ren Xinxin,
Liu Jia,
Zhang Chengsen,
Sun Jiamu,
Luo Hai
Publication year - 2013
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.6767
Subject(s) - chemistry , carboxylic acid , mass spectrometry , ionization , fast atom bombardment , desorption , dissociation (chemistry) , cyclodextrin , chromatography , ion , organic chemistry , adsorption
RATIONALE It is difficult to directly analyze carboxylic acids in complex mixtures by ambient high‐voltage‐assisted laser desorption ionization mass spectrometry (HALDI‐MS) in negative ion mode due to the low ionization efficiency of carboxylic acids. METHODS A method for the rapid detection of carboxylic acids in negative HALDI‐MS has been developed based on their inclusion with β‐cyclodextrin (β‐CD). RESULTS The negative HALDI‐MS signal‐to‐noise ratios (S/Ns) of aliphatic, aromatic and hetero atom‐containing carboxylic acids can all be significantly improved by forming 1:1 complexes with β‐CD. These complexes are mainly formed by specific inclusion interactions which are verified by their collision‐induced dissociation behaviors in comparison with that of their corresponding maltoheptaose complexes. A HALDI‐MS/MS method has been successfully developed for the detection of α‐lipoic acid in complex cosmetics and ibuprofen in a viscous drug suspension. CONCLUSIONS The negative HALDI‐MS S/Ns of carboxylic acids can be improved up to 30 times via forming non‐covalent complexes with β‐CD. The developed method shows the advantages of being rapid and simple, and is promising for rapid detection of active ingredients in complex samples or fast screening of drugs and cosmetics. Copyright © 2013 John Wiley & Sons, Ltd.