A simple and convenient dry-state SEIRS method for glutathione detection based on citrate functionalized silver nanoparticles in human biological fluids

Abstract

Surface-enhanced infrared absorption spectroscopy (SEIRS) using a dry-state method was established for the ultra-sensitive detection of glutathione using citrate functionalized silver nanoparticles (AgNPs) in human biological blood and serum samples. The signal intensity of glutathione was enhanced due to the hot-spots created by the aggregation of AgNPs causing the effective absorption of electromagnetic radiation in the IR region for molecular vibrations. The study revealed that the possibility of the interaction of silver with glutathione might rule out structural orientation, energy and affinity as the reason for the detection. The selective determination of glutathione was experimentally confirmed by performing controlled testing with other amino acids. The absorption peak at 3257.84 cm⁻¹ (NH₃⁺) was used for the quantitative analysis of glutathione when AgNPs were used as a chemical sensor in dry state SEIRS. A pre-treatment process was employed for human biological samples such as blood and serum in order to determine glutathione using AgNPs coupled with dry-state SEIRS analysis. A linear range was obtained for the quantitative determination of glutathione in human biological samples from 10 to 100 μg mL⁻¹ with a correlation coefficient (R²) of 0.993. The limit of detection was 1.74 μg mL⁻¹ and the limit of quantification was 5.30 μg mL⁻¹. The advantages of using the presented dry-state SEIRS are its simplicity, selectivity and sensitivity towards the analysis of glutathione using AgNPs in human biological blood and serum samples.