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On the isobaric space of 25‐hydroxyvitamin D in human serum: potential for interferences in liquid chromatography/tandem mass spectrometry, systematic errors and accuracy issues
Author(s) -
Qi Yulin,
Geib Timon,
Schorr Pascal,
Meier Florian,
Volmer Dietrich A.
Publication year - 2014
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.7075
Subject(s) - chemistry , isobar , isobaric process , mass spectrometry , chromatography , analytical chemistry (journal) , triple quadrupole mass spectrometer , tandem mass spectrometry , fourier transform ion cyclotron resonance , resolution (logic) , liquid chromatography–mass spectrometry , selected reaction monitoring , atomic physics , nucleon , physics , artificial intelligence , computer science , thermodynamics
RATIONALE Isobaric interferences in human serum can potentially influence the measured concentration levels of 25‐hydroxyvitamin D [25(OH)D], when low resolving power liquid chromatography/tandem mass spectrometry (LC/MS/MS) instruments and non‐specific MS/MS product ions are employed for analysis. In this study, we provide a detailed characterization of these interferences and a technical solution to reduce the associated systematic errors. METHODS Detailed electrospray ionization Fourier transform ion cyclotron resonance (FTICR) high‐resolution mass spectrometry (HRMS) experiments were used to characterize co‐extracted isobaric components of 25(OH)D from human serum. Differential ion mobility spectrometry (DMS), as a gas‐phase ion filter, was implemented on a triple quadrupole mass spectrometer for separation of the isobars. RESULTS HRMS revealed the presence of multiple isobaric compounds in extracts of human serum for different sample preparation methods. Several of these isobars had the potential to increase the peak areas measured for 25(OH)D on low‐resolution MS instruments. A major isobaric component was identified as pentaerythritol oleate, a technical lubricant, which was probably an artifact from the analytical instrumentation. DMS was able to remove several of these isobars prior to MS/MS, when implemented on the low‐resolution triple quadrupole mass spectrometer. CONCLUSIONS It was shown in this proof‐of‐concept study that DMS‐MS has the potential to significantly decrease systematic errors, and thus improve accuracy of vitamin D measurements using LC/MS/MS. Copyright © 2014 John Wiley & Sons, Ltd.