Liquid chromatography–mass spectrometric analysis of puerarin and its metabolite in human urine

Sensitive and selective detection of puerarin based on the hybrid of reduced graphene oxide and molecularly imprinted polymer

Puerarin, an important isoflavone, has been widely used for the treatment of angina and hypertension. In this work, we developed a novel electrochemical sensor for the detection of puerarin based on the hybrid of reduced graphene oxide (RGO) and molecularly imprinted polymer (MIP). The RGO/MIP sensor functions by target puerarin recognition and electro-oxidization via a two-proton and two-electron process, enabling the detection of puerarin with good selectivity and high sensitivity. The MIP layer was integrated on the surface of RGO by the electro-co-polymerization of o-phenylenediamine (monomer) and puerarin (template), resulting in high surface area, binding capacity, good conductivity and faster mass transfer. The nanostructure of the RGO/MIP hybrid was demonstrated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Experimental conditions involved in the sensor fabrication process were evaluated. Under the optimized condition, a wide linear range (0.02 μM ∼ 40 μM) and a low detection limit (0.006 μM) were achieved. The sensor was applied to detect puerarin in human urine and injection samples, and the result was comparable with that of the gold standard method of high-performance liquid chromatography (HPLC), indicating a promise in the further application to pharmacokinetics or therapeutic drug monitoring.

Quantitative liquid chromatography/time-of-flight mass spectrometry

Over the last decade, time-of-flight (TOF) instruments have increasingly been used as quantitation tools. In addition, because of their high resolving power, they can be used for verification of empirical formulas. Historically, TOF instruments have had limited quantitation capabilities because of their narrow dynamic range. However, recent advances have improved these limitations. This review covers the rationale for using TOF for LC detection, and describes the many methods currently in the literature for the quantitation of pharmaceuticals, environmental pollutants, explosives and many phytochemicals.