Detection of l-arginine

A microfluidic colorimetric sensing platform was developed which is rapid, sensitive and environmentally friendly for the selective determination of l-arginine based on its supramolecular interaction with nanocurcumin. The sensing mechanism is based on the formation of a stable nanocurcumin-l-arginine assembly through hydrogen bonding, electrostatic attraction and cation-π interactions, which leads to the appearance of a characteristic absorption band at 550 nm and a visible color change from yellow to deep red. The analytical performance of the sensing system was systematically optimized by studying the critical parameters such as nanocurcumin concentration, flow rate, temperature and reaction conditions. The incorporation of nanocurcumin with microfluidic technology showed a remarkable improvement in mass-transfer efficiency, reagent usage, waste generation and analytical sensitivity, which is in line with the principles of green analytical chemistry. The microfluidic platform exhibited excellent linearity under optimized conditions with the regression equation y = 0.400x + 0.0050 and a correlation coefficient (R ²) of 0.9993 in the concentration range of 0-20 µmol L^-1. The developed microfluidic platform showed a limit of detection (LOD) and limit of quantification (LOQ) of 0.825 nmol L^-1 and 2.5 nmol L^-1, respectively, which were about two-fold lower than the conventional batch method. The proposed method showed high precision, good repeatability and excellent selectivity towards l-arginine in the presence of potential interfering species. The developed platform was successfully applied to the analysis of pharmaceutical formulations and biological samples, with satisfactory recovery values and low matrix effects. In addition, the greenness and whiteness assessments showed that the proposed approach was environmentally sustainable. The developed nanocurcumin based microfluidic platform is a simple, rapid, cost-effective, eco-friendly analytical approach for the routine determination of l-arginine and represents a promising platform for future biomedical and point-of-care sensing applications.