Synthesis of crystalline silver nanoplates and their application for detection of nitrite in foods

The high-yield crystalline silver nanoplates were synthesized by mixing para-phenylenediamine (PPD) and silver nitrate with the addition of an appropriate amount of formic acid at low temperature. X-ray diffraction measurements show that the silver samples are pure face-centered cubic (fcc) phase with a preferred orientation of (1 1 1) direction. The silver nanoplates modified electrode (AgNP/GC) exhibits an excellent electrocatalytic activity toward the oxidation of nitrite ( NO 2 - ) . The corresponding linear range and detection limit are estimated to be from 1 × 10−5 M to 1 × 10−3 M (r = 0.999) and 1.2 × 10−6 M, respectively, at a signal-to-noise ratio of 3. It was successfully applied to the determination of nitrite in some food samples and the results were consistent with those obtained with the standard spectrometer procedure.