4-Aminothiophenol capped halloysite nanotubes/silver nanoparticles as surface-enhanced Raman scattering probe for in-situ derivatization and selective determination of nitrite ions in meat product.

ABSTRACT

Halloysite nanotubes loaded with 4-aminothiophenol capped silver nanoparticles (mHNTs-AgNPs4-ATP) composite was synthesized as a sensitive surface-enhanced Raman scattering (SERS) probe for the determination of nitrite ions in sausage and pork luncheon meat. The as-prepared composite was characterized by transmission electron microscope, X-ray diffraction spectroscopy and Fourier transform infrared spectroscopy. The as-synthesized mHNTs-AgNPs4-ATP composite with evenly distribution of AgNPs can provide in-situ derivatization site for sensitive and selective SERS detection of nitrite ions. Under acid condition, the 4-ATP capped on the AgNPs can be transformed into p,p'-dimercaptoazobenzene (DMAB) through nitrite-triggered diazo reaction. This efficient nitrite-triggered reaction can be used to detect nitrite via the characteristic peaks of DMAB at 1143 cm-1, 1392 cm-1, and 1434 cm-1. This SERS method has a wide logarithmic range of 0.0069-6.9 mg L-1, with detection limit of 0.78, 3.4, 0.51 µg L-1 at the peak of 1143 cm-1, 1392 cm-1, and 1434 cm-1, respectively. Besides, this method can be applied to detect nitrite ions in sausage and pork luncheon meat with relative standard deviation less than 10.3%, and the results were consistent with that analyzed by UV-Vis method. This method has good potential in efficient detection of meat product in food safety.