Determination of picric acid using micro CdS crystal-modified glassy carbon electrode.

Picric acid is a dangerous environmental pollutant due to its high toxicity, and the detection of picric acid in the environment is of great significance. The Cd²⁺ on the surface of CdS crystals can enrich negative ionic compound to form a complex in water. Therefore, the micro CdS crystals have been synthesised using thioacetamide and cadmium sulfate by means of a simple and cheap hydrothermal method for the detection of picric acid and were characterised by means of X-ray diffractometer, scanning electron microscopy, energy-dispersive spectrometer and AC impedance technique. The electrochemical reduction of picric acid at micro CdS crystal-modified glassy carbon electrode was investigated, revealing that the micro CdS crystals could catalyze picric acid, and the reduction mechanism of picric acid on the surface of micro CdS crystals was also discussed. Based on the reduction of picric acid at the modified electrode, a simple method of detection for picric acid was proposed by applying voltammetry, and a linear regression equation was obtained as I (10⁻⁵A) = 6160.53279 c (mol.L⁻¹) + 2.51034 (R = 0.9997) with a recoveries of 96.0–101.0% and relative standard deviations of 1.3–2.9% (n = 6), confirming very high sensitivity and selective detection of picric acid at the micro CdS crystal-modified glassy carbon electrode. [ABSTRACT FROM AUTHOR]