A facile, portable surface-enhanced Raman spectroscopy sensing platform for on-site chemometrics of toxic chemicals

We develop a high-performance portable Raman scattering-based sensing platform that can be directly used for detecting individual toxic chemicals and for the simultaneous determination of multiple toxic mixtures, such as malachite green (MG), crystal violet (CV), and methylene blue (MB). The 785 nm-optimized plasmonic gold nanorod (GNR)/tannic acid-mediated surface-enhanced Raman spectroscopy (gT-SERS) sensing chip shows high SERS performance with 3.11 % repeatability, 3.94 % spatial reproducibility, 1.25 x 104 enhancement, and 35d long-term stability. We demonstrate that the gT-SERS sensing benchtop and portable platforms combined with a single multivariate curve resolution-alternating least-squares decomposition model achieves a maximum limit of detection of 0.06 mu g/L for MB and 0.07 mu g/L for MG, respectively, which are approximately two orders of magnitude lower than the minimum required performance limit of MG and CV (2 mu g/L). In particular, our portable SERS sensing platform achieves good simultaneous determination performance of individual toxic chemicals from aquatic complex mixtures with an accuracy of >83 % for 1-3 mu g/L concentrations. Therefore, this facile and effective principle of our miniaturized SERS sensing platform will provide a basis as well as strategies for in-situ monitoring or surveillance of toxic chemicals in real aquatic environments.

Automated summary

A high-performance portable Raman scattering-based sensing platform has been developed for the detection of individual toxic chemicals and simultaneous determination of toxic mixtures with significantly low detection limits for methylene blue and malachite green, as well as good performance in determining individual toxic chemicals in complex aquatic mixtures.