Designing a Column-Switching High-Performance Liquid Chromatograph System for Enantiomeric Separation of Mouse Urinary D,L-Lactate

Abstract

We designed a circuit for turning the switching valve automatically, which is including mechanical units of motion, two timers, and electronic control units, though it is to combine two high-performance liquid chromatograph (HPLC) systems with a Rheodyne Model 7000 switching valve for separation of D- and L-lactate in biological samples has been reported in previous studies. The HPLC system comprised two HPLCs with an autosampler and two integrators. For more effective analysis, Total (D+L)-lactate fluorescent derivatives was isolated by a TSKgel ODS-80Ts column, when the peak of lactate derivatives appeared in the chromatogram on the ODS column, the valve position was changed by switching and then the isolated lactate derivatives was introduced into the chiral column automatically. Then the D- and L- enantiomers were separated by the chiral column. The utility of the analyzer system was tested for the determination of enantiomeric separation of urinary D, L-lactate in the mouse. It takes about 90 min to analyze one urine sample for a circulation. Before automation, we must turn the switching valve manually when the signal shows up, so that there must be someone always standby and only about 10 samples could be analyzed within one day. With the designed automatic column-switching HPLC system, the switching valve can be automatically turned at the setting time repeatedly and over 15 samples could be determined within one day. The automatic system makes the analysis of D-lactate be time-saving, convenient and reproducible.