Comparative Analysis of Reliability in On-Time Monitoring Data for NO₃–N, BTEX, and TOC: Commercialized Sensors versus Spectroscopic Methods

Real-time groundwater monitoring presents challenges owing to the high mobility of contaminants and the often expensive detection methods involved. This study aimed to address these challenges by leveraging real-time monitoring sensors to analyze groundwater pollutants, specifically focusing on compounds such as benzene, toluene, ethylbenzene, xylene (BTEX), NO3–N, and total organic carbon (TOC). This study attempted to provide a more efficient and cost-effective approach for monitoring groundwater quality using real-time sensors. The results obtained from the sensor were compared with analytical tools, such as gas chromatography–flame ionization detector (GC-FID) for BTEX analysis and ion chromatography (IC) for NO3–N. To simulate an underground aquifer, we fabricated a column allowing monitoring sensing probes to be installed. The results of the ultraviolet–visible (UV–vis) detection showed that the deposition of soil particles onto the sensor was crucial because of the blockage of UV–vis irradiation. Therefore, automated cleaning tools that clean the sensor every 5 s were installed. In actual groundwater field tests, the spectro::lyser V3 sensor demonstrated comparable accuracy to IC for NO3-N (r2 = 0.91) but lower accuracy for BTEX (r2 = 0.478). Despite this limitation, the sensor offers a valuable tool for initial detection and quantification of contaminants in groundwater samples.