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Confirmation of gentamicin and neomycin in milk by weak cation‐exchange extraction and electrospray ionization/ion trap tandem mass spectrometry
Author(s) -
Heller David N.,
Clark Susan B.,
Righter Herbert F.
Publication year - 2000
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(200001)35:1<39::aid-jms911>3.0.co;2-y
Subject(s) - chemistry , tandem mass spectrometry , electrospray ionization , mass spectrometry , ion trap , chromatography , electrospray , top down proteomics , extraction (chemistry) , selected reaction monitoring , neomycin , tandem , ion , organic chemistry , antibiotics , biochemistry , materials science , composite material
A new procedure for the confirmation of two aminoglycoside antibiotics in milk was developed and validated. This work is among the early applications of ion trap mass spectrometry for regulatory methodology, and it incorporates a novel weak cation‐exchange extraction. The procedure was validated for the confirmation of both gentamicin and neomycin at 30 ng ml −1 and above. Milk is first treated with acid and centrifuged. The supernate, excluding the fat layer, is buffered with sodium citrate to neutral pH. The extract is applied to a weak cation‐exchange solid‐phase extraction column. Aminoglycosides are eluted with acidified methanol. Following separation by ion‐pair liquid chromatography, analytes are ionized with an electrospray interface. Protonated molecular ions are selectively stored in an ion trap mass spectrometer, then collisionally dissociated to yield unique product ion spectra. Confirmation is based on matching spectral responses between samples and comparison standards consisting of a bona fide standard spiked into control extracts. Method performance was demonstrated with replicate samples of control milk, fortified milk, and milk containing incurred residues of each compound. Copyright © 2000 John Wiley & Sons, Ltd.