Ultrasensitive, highly selective and naked eye colorimetric recognition of d-penicillamine in aqueous media by CTAB capped AgNPs: applications to pharmaceutical and biomedical analysis

Herein, we are going to report a straightforward, highly selective and ultra sensitive naked eye colorimetric probe for the detection of d -penicillamine ( d -PA) in aqueous solution using cetyltrimethyl ammonium bromide (CTAB) capped colloidal silver nanoparticles (AgNPs) based on induced aggregation. The synthesized CTAB-AgNPs and their interaction with d -PA were characterized by different analytical techniques such as UV-Vis absorption spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) measurements and zeta potential measurements. The color of the CTAB-AgNPs solution changed from yellowish brown to colorless within short period of time after the successive addition of d -PA, resulting in a blue shift with quenching in the absorption spectra. Under the optimal conditions, a calibration plot of ( A 0 - A ) against concentration of d -PA was linear in the range of 0.1-0.6 μg mL −1 with a correlation coefficient of 0.9901. The concentration of d -PA was quantitatively determined using an UV-Vis spectrophotometer with a limit of detection (LOD) of 0.056 μg mL −1 (56 ng mL −1 ). In addition, the method shows an excellent selectivity and sensitivity towards d -PA over the other interfering biomolecules and cations tested. The accuracy and reliability of the method were further ascertained from the detection of d -PA from pharmaceutical and biomedical samples via a standard addition method, with percentage recoveries in the range of 98.32-102.94%. A plausible reason for the observed color changes is also discussed. The proposed method is simple, rapid, specific and highly selective and sensitive with good precision. Herein, we are going to report straightforward, highly selective and ultrasensitive naked eye colorimetric probe for the detection of d -PA in aqueous solution using CTAB capped AgNPs.