Detection of 3-nitro-1,2,4-triazol-3-one (NTO) by surface-enhanced Raman spectroscopy

3-Nitro-1,2,4-triazol-3-one (NTO) is an insensitive but powerful explosive. In this paper, Ag nanofilm was used as the surface-enhanced Raman spectroscopy (SERS) substrate for analysis of explosive NTO. The detection limit of NTO in deionized water (DI) water and an aged tap water were 35 μg/L (0.35 ng) and 0.35 mg/L (3.5 ng), respectively. pH variation in the range from 4.7 to 9.1 did not affect the position of SERS NTO bands, but affected the band intensity. The effect of eight common ions in natural waters on the SERS of 3.5 mg/L NTO was evaluated. K+, Na+, Ca2+ and Mg2+ at 100 mg/L did not have significant negative effect on the SERS of 3.5 mg/L NTO as NTO has a stronger affinity for Ag nanofilm than that for the cations. SO42−, CO32− and NO3− (100 mg/L) also did not have significant negative effect on the SERS of 3.5 mg/L NTO. Cl− in the range of 1–50 mg/L can activate the SERS of NTO. At the high concentration of 100 mg/L Cl−, the activation and deactivation of the SERS of 3.5 mg/L NTO were both observed, but the overall average effect of Cl− was not very negative.