Atmospheric pressure chemical ionization and atmospheric pressure photoionization for simultaneous mass spectrometric analysis of microbial respiratory ubiquinones and menaquinones

✍ Scribed by Roland Geyer; Aaron D. Peacock; David C. White; Cory Lytle; Gary J. Van Berkel

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 186 KB
• Volume: 39
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.670

✦ Synopsis

Abstract

An atmospheric pressure photoionization (APPI) source and an atmospheric pressure chemical ionization (APCI) source were compared for the selective detection of microbial respiratory ubiquinone and menaquinone isoprenologues using tandem mass spectrometry. Ionization source‐ and compound mass‐dependent parameters were optimized individually for both sources, using the available quinone standards. Detection levels for the two ion sources were determined with ubiquinone‐6 (UQ~6~) and menaquinone‐4 (MK~4~, vitamin K~2~) standards using flow injection analysis and selected reaction monitoring (SRM). With APPI the calculated lower limit of detection (LLOD) was 1.7 fmol µl^−1^ for UQ~6~ and 2.2 fmol µl^−1^ for MK~4~ at a signal‐to‐noise ratio of 3. These LLODs were at least three times lower than with APCI. The selectivity of detection afforded by SRM detection reduced complex mixture analysis to 3 min per sample by eliminating the need for chromatographic separations. The detection method was successfully applied to quinone quantification in a variety of environmental samples and cell cultures. Adequate amounts of respiratory quinones can be extracted and quantified from samples containing as low as 2 × 10^7^ cells. Copyright © 2004 John Wiley & Sons, Ltd.