Determination of γ-hydroxybutyrate in human urine samples by ion exclusion and ion exchange two-dimensional chromatography system

A two-dimensional ion chromatography system was developed for the determination of γ-hydroxybutyrate (GHB) in human urine samples. Ion exclusion chromatography was used in the first dimensional separation for elimination of urine matrices and detection of GHB above 10 mg L−1, ion exchange chromatography was used in the second dimensional separation via column-switching technique for detection of GHB above 0.08 mg L−1. Under the optimized chromatographic conditions, the ion exclusion and ion exchange chromatography separation system exhibited satisfactory repeatability (RSD < 3.1%, n = 6) and good linearity in the range of 50-1000 mg L−1 and 0.5-100 mg L−1, respectively. By this method, concentrations of GHB in the selected human urine samples were detected in the range of 0-1.57 mg L−1. The urine sample containing 0.89 mg L−1 GHB was selected to evaluate the accuracy; the spiked recoveries of GHB were 95.9-102.8%. The results showed that the two-dimensional ion chromatography system was convenient and practical for the determination of GHB in human urine samples.