Reducing Interferences from Organic Matter during Optical Environmental Detection using SERS-Silent Region Nanosensors: A Case of Nitrite Detection
Meichun Liu, Zhiyang Zhang, Yanzhou Wu, Yan Chen, Peng Liu, Tianyu Zhou, Xuming Zhuang, Lingxin Chen
Abstract
Optical detection techniques are frequently used in environmental monitoring due to their high sensitivity and stability; however, to decrease the optical interferences from environmental matrix remains challenging. Herein, to decrease the optical interferences from dissolved organic matter (DOM), a surface-enhanced Raman scattering (SERS)-silent region (1800–2800 cm –1 ) sensor has been studied for the detection of NO 2 – (a model pollutant) in the presence of DOM. 4-Ethynylaniline (4-EA) was selected as the sensing molecule. The signal band (2205 cm –1 ) and the internal standard band of 4-EA (1985 cm –1 ) in the SERS-silent region are used for the quantitative analysis of NO 2 – . Since the SERS-silent region can well avoid the overlapping with the DOM signal, the dual-silent band ratio I 2205 /I 1985 exhibits outstanding anti-interference ability toward different common organic matter. Compared with the traditional UV–vis detection, this method maintains a higher sensitivity (with a detection limit of 10 –7 M) and a better accuracy (detection recovery ranges from 89.9 to 109.7%) for NO 2 – detection in real samples. Furthermore, this SERS dual-silent region sensor has been successfully employed in an environmental survey of a local river. These findings imply that the SERS-silent nanosensor provides a way to develop accurate optical detection techniques for environmental monitoring.