An Efficient In-Situ Bimetallic Paper-Based Sensor for Both Iron Ii and Iii in Real Samples

Herein, we report a colorimetric detection of iron II and III through modulation of the localized surface plasmon resonance (LSPR) at 450 nm, while presenting red (482 nm) and blue (400 nm) shifts for two iron forms, respectively. Silver nanoparticles functionalized with Bougainvillea leaves extract (BV-AgNPs) were utilized as such and their impregnated paper-based sensor. BV-AgNPs were found spherical to hexagonal shapes and average size of 19.5 ±0.46 nm as affirmed by LSPR, dynamic light scattering (DLS) and transmission electron microscopy (TEM). Interactions of the fabricated probe with various aqueous heavy metal ions, provided rapid detection, higher sensitivity and significant selectivity towards iron II and III, as validated by FTIR, TEM and DLS. BV-AgNPs offers the lowest limit of detections for iron II and III (0.123 and 3.89 nM, respectively) with significant linearity and recoveries in real samples. Thus, eco-friendly and simplest approach of paper-based sensor also offers in-situ monitoring.