Determination of N-acetyl-L-Cysteine and Glutathione by the colorimetric method with the use of a smartphone as a detector

Abstract

The possibility of determining N-acetyl-L-cysteine or Glutathione based on the reaction with Cu(II)-neocuproine complex according to a simple procedure and using a spectrophotometer or a smartphone as detectors is described. The analytical applicability of the methods was tested and the excellent characteristics of the smartphone as a detector in the analysis of pharmaceuticals were observed. The prepared reaction solutions were yellow and their absorbance was measured at a wavelength of 450 nm. Also, due to the yellow color of the solution, the intensity of the blue RGB channel decreased with increasing thiol concentration. The proposed procedures allow the determination of both thiols in the linear dynamic range from 3.0×10− 6 to 2.0×10− 4 mol L-1 for a spectrophotometer as a detector, or from 6.0×10− 6 to 2.0×10− 4 mol L-1 for a smartphone as a detector. The obtained results indicate the usefulness of the CUPRAC method in the analysis of thiols, but also represent a smartphone as a comparable detector with a UV-Vis spectrophotometer.