L‐cysteine capped silver nanoparticles as chiral recognition sensor for ketoprofen enantiomers

AbstractA simple, inexpensive but effective approach for visual chiral recognition of ketoprofen enantiomers was developed using L‐cysteine capped silver nanoparticles (L‐Cys‐AgNPs) as a colorimetric sensor. Upon the addition of R‐ketoprofen to L‐Cys‐AgNPs, rapid aggregation occurred, and the solution changed color from yellow to green. However, the presence of S‐ketoprofen did not induce any color change. The results were characterized using UV‐Vis, FESEM, FT‐IR, SERS, and zeta potential measurements. The chiral assay described in this work is easily distinguished with the naked eyes or using a UV‐Vis spectrometer. The sensor revealed a good linear response to ketoprofen enantiomers in the concentration range of 8.33–33.3 μM with a detection limit of 4.52 μM and relative standard deviation of 3.73%. The proposed method was utilized for the determination of ketoprofen racemic mixtures in water samples and commercial tablets. The method excels by its simplicity, low cost, and good availability of materials.