Simultaneous and rapid detection of polychlorinated phenols in water samples by surface-enhanced Raman spectroscopy combined with principal component analysis

In this work, a simple, high-throughput, and sensitive analytical method based on surface-enhanced Raman spectroscopy (SERS) and principal component analysis (PCA) was fabricated for simultaneous and rapid determination of three polychl-orinated phenols (PCPs) including 2,4-dichlorophenol (2,4-DCP), 2,4,5-trichlorophenol (2,4,5-TCP), and 2,3,4,6-tetrachloro-phenol (2,3,4,6-TeCP). The aggregated Ag nanoparticles (AgNPs) induced by inorganic salt ions were used as sensitive SERS substrate, and the electromagnetic field distribution of AgNPs with different distances was simulated by finite difference time domain (FDTD) to verify the theory feasibility. The high throughput and rapid detection can be achieved by commercial 96-pore plate. Under the optimum conditions, the linear relationship between the Raman intensity and the concentrations of PCPs was established with satisfied correlation coefficient. The limits of detection (LOD) for 2,4-DCP, 2,4,5-TCP, and 2,3,4,6-TeCP are 0.27 mg L-1, 0.09 mg L-1, and 0.10 mg L-1 by rules of 3 sigma, respectively. The simultaneous quantitative analysis can be achieved thanks to the independent Raman characteristic peaks of three PCPs. Afterwards, the PCA method was used to eliminate the limitations of overlapping of characteristic Raman peaks in structural analogues of 2,4-DCP, 2,4,5-TCP, and 2,3,4,6-TeCP. The recovery experiments including single PCPs and mixed PCP samples show satisfied recoveries ranging from 85.0 to 113.9% and 80.4 to 114.0% with RSDs in range of 0.4-9.5% and 1.1-10.7%, respectively. The proposed method shows great potentials in rapid, high-throughput, and sensitive monitoring of the contaminants in water and pesticide samples with similar structure.

Automated summary

A high-throughput and sensitive analytical method based on SERS and PCA was developed for the simultaneous determination of three PCPs. The method achieved rapid detection on a 96-well plate, established linear relationships with satisfactory LODs, and successfully eliminated interference from structural analogues using the PCA method. Recovery experiments showed satisfying results, indicating the method's potential for monitoring contaminants in water and pesticide samples.