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Filter paper cards contaminated with EMLA cream produce artefacts on acylcarnitine analysis
Author(s) -
Kuster T.,
Torresani T.,
Kleinert P.,
Durka S.,
Neuheiser F.,
Heizmann C. W.,
Troxler H.
Publication year - 2004
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1023/b:boli.0000043024.08450.0c
Subject(s) - chromatography , chemistry , prilocaine , derivatization , lidocaine , electrospray ionization , mass spectrometry , anesthesia , medicine
Summary: Electrospray ionization tandem mass spectrometry is a widely applied method for the analysis of acylcarnitines in blood samples spotted on filter paper cards (Guthrie cards). When the filter paper cards are contaminated by EMLA cream, highly intense signals at m / z 221 and 235 are detected under ESI‐MS/MS conditions, monitoring for precursors of m / z 85. These signals correspond to the active ingredients prilocaine and lidocaine in EMLA and overlap with the signals from the isotopically labelled internal standards ( 2 H 3 )propionyl carnitine and ( 2 H 3 )butyrylcarnitine. This interference prevents the proper quantification of the two short‐chain acylcarnitines when samples are analysed without derivatization.