Low-cost Synthesis of Gold Nanoparticles from Reused Traditional Gold Leaf and Its Application for Sensitive and Selective Colorimetric Sensing of Creatinine in Urine

Background: Gold nanoparticles (Au NPs) are normally prepared using standard gold (III) trichloride which is much expensive and irritant. This work is aimed at demonstrating simple and low-cost synthesis of Au NPs from the reused traditional gold leaf which is cost-free and less toxic. Methods: The reused gold leaf was donated by the local temple. It was digested and used as the pre-cursor for the preparation of the Au NPs by Turkevich method. Poly (vinyl alcohol) (PVA) was employed as a stabilizer. The as-prepared Au NPs were applied for the colorimetric determination of creatinine in urine without any sample pretreatment. Results: Long-term stability of the gold colloids was achieved for at least 3 months. Morphology and purity of the as-prepared Au NPs were the same as the ones prepared from standard gold (III) salt and standard gold foil. Colorimetric response of the Au NPs was linear to the standard creatinine up to 200 mg L-1. The limit of detection (0.16 mg L-1. or 1.41 mu M) was enough sensitive for urinary creatinine detection in patients with kidney disease. Good recoveries (97-108%) and fast analysis time (3 min) were achieved. The developed method was successfully validated against the HPLC method. Conclusion: Facile and cost-effective synthesis of the Au NPs from the reused traditional gold leaf, was accomplished. The as-prepared Au NPs were successfully applied for the determination of urinary creatinine with high sensitivity and selectivity.