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.

The abuse of paramethoxymethamphetamine (PMMA) and 3,4-methylenedioxymethamphetamine (MDMA) among young people is increasingly serious and has become a public health problem. Since enantiomers of MDMA and PMMA are metabolized at different rates in the body and exhibit different neurotoxicity in tissues, we have developed a simple method for simultaneous enantiomeric determination of PMMA and MDMA, using parallel dual capillary immunoaffinity columns coupled with tandem mass spectrometry. Linear calibration curves were obtained in concentration ranges of 100–1000 ng/mL, with a limit of quantitation of <22 ng/mL. Good interday accuracy and precision were achieved with this method. Besides filtering the urine sample through a 0.45 μm MILLIPORE membrane, no other sample pretreatment was needed, and no toxic organic solvent was used. It is a rapid, environmentally friendly safe method, and could be applied for routine enantiomeric analysis of PMMA and MDMA in the pharmaceutical industry, forensic science, and environmental analysis.