a sensitive and selective colorimetric probe for cimetidine determination based on surface plasmon resonance of chitosan-encapsulated gold nanoparticles

In the present study, a simple, facile, and highly selective colorimetric method is reported for cimetidine assay based on antiaggregation of in situ formed gold nanoparticles (aunps). the partially aggregated aunps were produced using ascorbic acid and chitosan in acidic media. the presence of cimetidine during formation of aunps led to the production of more dispersed nanoparticles resulting in a color change from blue to red. consequently, monitoring of surface plasmon resonance absorbance of in situ formed aunps presents a reliable colorimetric probe for the determination of cimetidine. this plasmonic nanoprobe exhibits highly sensitive detection of cimetidine at concentrations as low as 2.7 ng ml−1 and is capable of quantitative assay of cimetidine over a range of 3.3–65.6 ng ml−1. the relative standard deviation corresponding to eight replicate determinations of 49.2 ng ml−1 of cimetidine was 4.1%. the method was highly selective toward many cations, anions, and sulfur-containing compounds. this sensing nanoprobe was effectively used for the rapid determination of cimetidine in tablet formulations and human serum samples.