Ordered mesoporous carbon as sorbent for the extraction of N-nitrosamines in wastewater and swimming pool water

- Eight polar and non-polar NAs were determined simultaneously in water samples.
- Oxidative surface-modified ordered mesoporous was applied as μ-SPE sorbent.
- An isotopically-labeled NA was used as internal standard.
- Despite the complex nature of the matrices, negligible matrix effects were observed.

The analysis and determination of N-nitrosamines (NAs) in water samples are challenging and demanding. In this study, a simple, reliable, and practical methodology is reported for the quantitative determination by gas chromatography-tandem mass spectrometry with electron impact ionization (EI) and triple quadrupole analyzer (GC-EI-MS/MS) of eight NAs after micro-solid-phase extraction (μ-SPE) from wastewater and swimming pool water. Thirty milligram of an ordered mesoporous carbonaceous material, oxidative surface-modified CMK-3, enclosed within a porous polypropylene membrane bag, were used as sorbent for μ-SPE. A central composite design approach was applied to optimize the μ-SPE parameters. An isotopically-labeled NA was used as internal standard. Under the optimized conditions, μ-SPE-GC-EI-MS/MS was validated for an NA concentration range of between 0.1-100 ng/mL. The precision of the method was evaluated and an average relative standard deviation of 4.8% (n = 8) for a standard solution spiked at 50 ng/mL of each NA was obtained. The limits of detection were measured to be in the range of 0.005-0.283 ng/mL. Domestic wastewater and swimming pool water samples were used to evaluate the applicability of the method. NAs were detected in swimming pool water and wastewater at concentrations of <2 ng/mL and 11 ng/mL, respectively.