Department of Chemistry
Project 3: Methods of Selective Extraction, Concentration, and Detection of N-Nitrosamines
N-Nitrosodimethylamine (NDMA) is a probable human carcinogen. While mass spectrometry is an effective approach for detecting N-nitrosamines such as NDMA, samples need to be shipped to the laboratory and analysis requires considerable expertise and expensive equipment. The goal of this project is to overcome these barriers by creating polymer absorbents and optical sensing methods that are compatible with citizen science.
Project 3 will create materials that are compatible with detection of hazardous N-nitrosamines in water and will make the methods available to affected communities. To improve detection, specific materials that absorb N-nitrosamines (Recognition-Solid Phase Extractor [R-SPE]) will be developed and sensors will be created that are compatible with optical sensing. Resulting tools will be instrumental in the development of convenient field-deployable methods that exploit smartphone technology. Both colorimetric and emissive detection methods can be integrated with smartphones. Resulting data will offer more comprehensive information of risk and how seasons, weather, and human interventions impact the exposure risks.
The ability to understand the risks posed by N-nitrosamines is limited due to complex detection methods. Currently, methods to detect aqueous N-nitrosamines typically consist of extracting the compound from the water, concentrating the sample in organic solvent, performing chromatographic separation, and then analysis via mass spectrometry. These methods are time consuming and costly.
Project 3 has three aims with the objective of departing from the laboratory-oriented burden of detecting N-nitrosamines to devising an economical and convenient product-oriented detection solution.
- Aim 1: Create and deploy porous absorptive polymer films and particles with recognition elements specific for N-nitrosamines (Recognition-Solid Phase Extractor [R-SPE]).
- Aim 2:Create and apply a novel NDMA sensor that exploits NDMA fragmentation products.
- Aim 3: Deploy a fieldable device effective for use by community members to perform Citizen Science.
The approach in coming up with a diagnostic device is to first tailor the chemical structure of R-SPE materials to interact with N-nitrosamines. By doing so, this enables the creation of materials that optimally extract and thereby concentrate these analytes for detection down to sub-ng/L of nitrosamines, such as NDMA. The second phase is to create NDMA optical sensors that exploit photolytic processes of N-nitrosamines. Key aspects of this phase are to perform quantitative measurements of emission signals and to determine the detection limits from different methods. The final stage is to leverage optical sensors by creating R-SPE cartridges or test strips that will reveal the presence of N-nitrosamines in water samples. The signal will interface with existing smartphone-based methods, thus making the readout of the results more readily accessible.
Throughout the development stages, the sharing of information with other Projects and Cores will greatly enhance the understanding of public health risks. Moreover, with the support of the Community Engagement Core and community members of Wilmington, MA, the real-world testing of this device in the field can validate the viability of this turn-key method for detecting NDMA and other N-nitrosamines in water. Ultimately, the project findings will contribute to the work of devising methods to remove N-nitrosamines from a critical route of exposure, namely drinking water.