Real-time monitoring of aqueous total N-nitrosamines by UV photolysis and chemiluminescence

N-nitrosamines such as N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), and N-nitrosopyrrolidine (NPYR) have been established as potent carcinogens that can induce diverse types of cancer. Several studies have extensively investigated the accurate quantification of total N-nitrosamines (TONO) and the intricate nature of the matrix in which they are detected. The potential for the formation of N-nitrosamines in post-combustion CO₂ capture (PCCC) and water treatment has raised concerns. This study outlines a unique method for the quantification of TONO in aqueous matrices using UV photolysis and the subsequent detection of NO by chemiluminescence. This method offers benefits such as operation in the continuous mode and handling of high sample flow rates to achieve a low limit of detection (LOD) and a low limit of quantification (LOQ). The observed LODs for the individual N-nitrosamines of NDMA, N-nitrosomorpholine (NMOR), N-nitrosodibutylamine (NDBA), and NPIP range between 0.06 and 0.2 µM at a sample flow rate of 0.25 mL/min, while the LOD range is reduced to between 0.02 and 0.06 µM at 0.75 mL/min. Linear responses for the NO produced from specific N-nitrosamines are observed between 0.5 and 10 µM. The developed method is resistant to interfering chemicals (i.e., nitrite, amines, and carbonyls) and exhibits high specificity.