Determination of lysergic acid diethylamide (LSD) by application of online 77 K fluorescence spectroscopy and a sweeping technique in micellar electrokinetic chromatography

The principal advantage of the use of Shoplʹskii effect (low temperature spectrum) is that spectral sharpening occurs both in absorption and emission. However, thus far using the technique of capillary electrophoresis/low temperature fluorescence spectroscopy (CE/LTFS) either at 77 or 4.2 K remains difficult to obtain an on-line spectrum, if the analyte is present at low concentration. This paper examines the feasibility of combining the techniques of online concentration and CE/LTFS to identify LSD and related compounds in urine at 77 K. To improve sensitivity, sweeping-micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were used for on-line concentration which resulted in detection limits of ∼20 ∼60 ppt, respectively.