ABSTRACT
Solid-phase extraction and column-trapping preconcentration are combined to enhance HPLC-nuclear magnetic resonance (HPLC-NMR) and applied to metabolite profiling in biological samples. Combining the two signal enhancement techniques improved the NMR signal substantially such that we were able to identify 2-hydroxyibuprofen, carboxyibuprofen, and unmetabolized ibuprofen molecules from a small urine sample after a therapeutic dose of ibuprofen. The hyphenated SPE/column-trapping method resulted in an excellent overall signal enhancement of up to 90-fold.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/metabolism , Chromatography, High Pressure Liquid/methods , Ibuprofen/metabolism , Nuclear Magnetic Resonance, Biomolecular/methods , Solid Phase Extraction/methods , Anti-Inflammatory Agents, Non-Steroidal/urine , Chromatography, High Pressure Liquid/instrumentation , Humans , Ibuprofen/urine , Nuclear Magnetic Resonance, Biomolecular/instrumentation , Tablets , Time FactorsABSTRACT
A miniature cylindrical ion trap mass spectrometer is described, and preliminary data are presented. Functionality and performance of laboratory-scale instruments have been maintained to the extent possible in this battery-operated mass spectrometer. Capabilities include tandem mass spectrometry experiments. Custom-designed electronic components include the RF scanning and amplification system, data acquisition components, and lens power supplies, as well as a custom-software application. Direct leak and membrane introduction inlet systems are used for sample introduction. A mass/charge range of approximately 250 Th with unit mass resolution has been demonstrated.