A simple and high throughput parallel dual immunoaffinity liquid chromatography-mass spectrometry system for urine drug testing

A simple and rapid method for direct quantitation of drugs in human urine samples was developed using a system composed of an automatic column switch and two home-made capillary immunoaffinity columns (CIACs, 100 μm × 15 cm). Before being injected by an autosampler into the system, the urine sample was filtered through a 0.22 μm membrane. The alternating column regeneration was achieved by using two identical CIACs. One column underwent analyte elution while the other column underwent column regeneration simultaneously. 6-Acetylmorphine (6AM) and oxycodone (OCOD) were studied as examples of opiates in urine. Linear calibration curves were obtained in the concentration ranges of 40–200 ng mL−1 and 50–400 ng mL−1, with a limit of quantitation of 22 ng mL−1 and 47 ng mL−1 for 6AM and OCOD, respectively. The results of this method exhibited good inter-day accuracy and precision. Furthermore, the present method was successfully applied to the determination of 6AM in urine samples of drug abusers.