A novel spectrophotometric method based on plasmonic nanoparticles for nicotine detection.

In this paper, a spectrophotometric method for nicotine detection based on plasmonic nanoparticles (AuNPs and AgNPs) is proposed. Due to their specific properties, plasmonic nanoparticles have become interesting to use in the development of sensitive analytical methods. The localized surface plasmon resonance (LSPR) absorption bands for AgNPs and AuNPs with a wavelength at 395.5 nm (A395.5) and 543.5 (A543.5) nm, respectively, are used for the detection. Experimental variables such as solvent type and pH were optimized so as to determine the optimum working conditions. The analytical calibration curve for both AgNPs and AuNPs based on spectrophotometric methods was prepared with nicotine concentrations range from 0.10 to 5.00 µM (R2 = 0.9903) and 0.001-0.300 µM (R2 = 0.9960), respectively. The detection limits were found to be 0.001 µM for AuNPs based method and 0.09 µM for AgNPs based method. The proposed nanoparticle-based spectrophotometric methods showed a good stability, selectivity and low detection limit.

Synthesis and characterization of novel nano-chitosan Schiff base and use of lead (II) sensor.

A new kind of nano-chitosan Schiff base ligand (CHNS) with particle size of 34 nm was formed by the reaction between the 2-amino groups of glucosamine residue of nano-chitosan and a 2,5-dihydroxybenzaldehyde. The chemical structures of the nano-chitosan and nano-chitosan Schiff base were characterized by FT-IR spectra, particle sizer, zeta potential, and elemental analysis. A new, simple and effective chemically modified carbon paste electrode with CHNS was prepared and used as a lead (II) sensor. The prepared electrode was characterized using scanning electronic microscopy (SEM-EDX) and cyclic voltammetry (CV). The modified electrode showed only one oxidation peak in the anodic scan at -0.34 V (vs. Ag/AgCl) for the oxidation of lead (II). The dedection limit (LOD) was calculated as 1.36×10(-7) for a 10-min preconcentration time at pH 6.0.