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A zwitterion-exchange stationary phase (ZIXSP) was prepared for the separation of the mixture of organic bases, organic acids and amino acids by high performance liquid chromatography (HPLC). It was synthesized by the reaction of cyanuric chloride with sulfanilic acid and then bonded onto the silica gel on which the silane coupling agent was preboiided. The chromatographic behaviours of the prepared ZIXSP revealed that the capacity factors of each analyte varied with the pH value of the mobile phase. By applying the concept of acid-base equilibrium the correlation W e e n the capacity factor on the ZIXSP and pH of the mobile phase could be explained reasonably. Based on our results, it is concluded that ZIXSP is a zwitterion exchanger that additionally provides R-X chargetransfer interaction and hydrophobic interaction functions.

In this study, the Pd/BiVO4 composite was prepared by hydrothermal method as an electrochemical sensing material for epinephrine. X-ray diffraction, scanning electron microscopy, and a transmission electron microscope were used to characterize the samples. In the electrochemical detection system, cyclic voltammetry and differential pulse voltammetry were applied to measure the concentration of the epinephrine solution (0.9–27.5 µM) with the Pd/BiVO4-coated glassy carbon electrode. As a result, the oxidation peak current of Pd/BiVO4/GCE demonstrated good linearity with the epinephrine concentration. The detection limit of the epinephrine concentration by cyclic voltammetry and differential pulse voltammetry were 0.262 µM and 0.154 µM, respectively. Additionally, the proposed sensing material exhibited good reproducibility, stability, and selectivity. A plausible sensing mechanism was proposed.

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).