Magnetic nanoprobes for rapid detection of copper ion in aqueous environment by surface-enhanced Raman spectroscopy

Excessive copper ions in drinking water could cause serious health issues, such as gastrointestinal disorders and cirrhosis, and they are associated with Alzheimer's disease. ICP-OES, ICP-MS, and AAS are the most common methods of copper ion determination. However, the high cost of sample preparation and labor limit the possibility of on-site detection. In this study, rapid monitoring of copper ion through the SERS technique was evaluated. Fe3O4@SiO2-Ag-4MBA nanoparticles were investigated as SERS-activated magnetic nanoprobes. These magnetic nanoprobes underwent superparamagnetism for rapid aggregation in seconds and provided selectivity in sensing copper ions. According to the dose-response curve of the SERS spectra, the limit of detection (LOD) was 0.421 ppm and the dynamic range was from 0.5 to 20 ppm in the presence of other metal ions. Copper ion detection through SERS was highly correlated with ICP-OES (R2 = 0.95, slope = 0.974). These results demonstrate that magnetic nanoprobes may ultimately be used in a platform for on-site detection.