Fast liquid chromatography separation and multiple‐reaction monitoring mass spectrometric detection of neurotransmitters

We describe here the fast LC‐MS/MS separation of a mixture of neurotransmitters consisting of dopamine, epinephrine, norepinephrine, 3,4‐dihydroxybenzylamine (DHBA), salsolinol, serotonin, and γ‐aminobutyric acid (GABA). The new UltiMate® 3000 Rapid Separation system (RSLC) was successfully coupled to the 4000 QTRAP mass spectrometer operating in multiple‐reaction monitoring (MRM) mode. The separation was attained using a 100 mm length, 2.2 μm particle size Acclaim column at a flow rate of 0.5 mL/min. The column back pressure was 350 bar, while the total run time including column re‐equilibration was 5.2 min. The peak resolution was minimally affected by the fast separation. The RSLC‐MRM separation was found to have a precision range based on peak area for 50 replicate runs of 2–5% CV for all analytes, and the reproducibility of the retention time for all analytes was found to range from 0–2% CV. The described method represents an almost seven times shorter analysis time of neurotransmitters using LC/MRM which is very useful in screening large quantities of biological samples for various neurotransmitters.