Ultra-sensitive hexagonal wurtzite zinc oxide-based electrochemical sensor for specific recognition of environmental trace N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine

Emerging contaminant N-(1,3-dimethylbutyl)-N '-phenyl-p-phenylenediamine has caused severe threats to eco-systems, necessitating the development of highly sensitive detection methods. Herein, a reliable and ultra-sensitive electrochemical sensor based on a carbon paste electrode modified by hexagonal wurtzite zinc oxide was developed for selective determination and degradation of N-(1,3-dimethylbutyl)-N '-phenyl-p-phenylenediamine. Experimental results demonstrated the successful application of the sensor for detecting N-(1,3-dime-thylbutyl)-N '-phenyl-p-phenylenediamine in soil samples. The contaminant contents were found to be 1.46-24.68 nmol L-1 in Zhengzhou City and 1.99-11.3 nmol L-1 in Pingdingshan City, respectively, along with a satisfactory recovery rate. Density functional theory calculations revealed that the hexagonal wurtzite zinc oxide crystal significantly decreased the activation energy of catalytic conversion compared to cubic sphalerite, resulting in a notable improvement in sensor response. Cryogenic electron microscopy technique further confirmed that the electrocatalytic degradation product of N-(1,3-dimethylbutyl)-N '-phenyl-p-phenylenediamine was not toxic N-(1,3-dimethylbutyl)-N '-phenyl-p-phenylenediamine quinone. Under optimal analysis conditions, the sensor achieved widely low as well as high linear ranges (0.1-800 nmol L-1 and 0.9-20 mu mol L-1) with a low detection limitation (33 pmol L-1), indicating that such a highly sensitive and cost-effective electrochemical sensor has the potential for environmental pollutants monitoring.