Capillary Ultrahigh Performance Liquid Chromatography with Elevated Temperature for Sub-One Minute Separations of Basal Serotonin in Submicroliter Brain Microdialysate Samples

摘要

Improving the time resolution in microdialysis couplednto high performance liquid chromatography (HPLC) requiresnthat the volume of the separation system bendecreased. A low-volume separation permits smallernmicrodialysate volumes to be injected without suffering ansensitivity loss from dilution. Thus, improved time resolutionncan be achieved with offline analysis simply byndecreasing the separations system volume. For onlinen(near real-time) analysis, there is a further requirement.nThe separation speed must be at least as fast as thensampling time. Here, the combined use of high columnnpressures and temperatures, sub-2-μm stationary phasenparticles, capillary columns, and sensitive, low deadvolumendetection resulted in a retention time for thenneurotransmitter serotonin of less than 1 min in a 500nnL dialysate sample volume. Two sensitive detectors,nphotoluminescence following electron transfer (PFET) andnelectrochemical, were used for the detection of subnanomolarnconcentrations of serotonin in brain microdialysatensamples. The general principles developed are applicablento a wide range of separations with the additional advantagesnof increases in sample throughput and decreasesnin mobile phase usage.