Integrated lab-in-syringe/lab-on-valve flow system for the synthesis of EDTA-capped silver nanoparticles and determination of creatinine

A fully integrated lab-in-syringe/lab-on-valve flow system was developed for the synthesis of EDTA-capped silver nanoparticles and their subsequent application in the spectrophotometric determination of creatinine. This work presents the first use of a lab-in-syringe system for nanoparticle synthesis and the first fully integrated flow system that unites both synthesis and analysis steps within a single system. The method is based on the aggregation of silver nanoparticles induced by creatinine in an alkaline medium, with detection performed by spectrophotometric measurement of the resulting colour change. The method was successfully applied to the determination of creatinine in human serum samples. Analytical validation of the method confirmed a limit of detection (LOD) of 0.04 mg/L and a limit of quantification (LOQ) of 0.14 mg/L. A linear range between 0.14 and 3.00 mg/L was obtained, with a relative error (RE) of 6.7 % and a coefficient of variation (CV, n=8) of 8.0 %, confirming satisfactory accuracy.