Colorimetric determination of xanthine in urine based on peroxidase-like activity of WO3 nanosheets

• Published in: Talanta (Oxford) 2019-11, Vol.204, p.278-284
• Main Authors: Li, Zhihong, Liu, Xinyi, Liang, Xiao-Hua, Zhong, Jianhai, Guo, Liangqia, Fu, Fengfu
• Format: Article
• Language: English
• Subjects: Colorimetric sensor; H2O2; Peroxidase mimetics; WO3; Xanthine
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2019.06.003

Two-dimensional WO3 nanosheets were prepared by ultrasonic exfoliation of bulk WO3·2H2O in water and characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman, dynamic light scattering. The nanosheets were discovered to possess the peroxidase-like catalytic activity, which can catalyze the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine by H2O2. The catalytic mechanism was also investigated by the scavenger experiments. Taking advantage of the peroxidase-like activity of WO3 nanosheets, a facile colorimetric method for xanthine was developed by combining the oxidation reaction of xanthine catalyzed by xanthine oxidase. The linear range for xanthine was ranged from 25 to 200 μmol L−1. The limit of detection for xanthine was 1.24 μmol L−1. The colorimetric method was applied to determine xanthine in urine samples. [Display omitted] •Two-dimensional WO3 nanosheets were prepared by a facile and environmental-friendly method.•WO3 nanosheets were discovered to possess the peroxidase-like catalytic activity.•A facile colorimetric method for xanthine was developed with a LOD of 1.24 μmol L−1.•Abnormal high concentration of xanthine in urine samples can be easily read out by naked eyes.