The presence of micro and nano plastics in the environment and their impact on the various life forms within it are of principle concern around the globe. However, whilst a considerable amount of work has been done on the detection of microplastics, many challenges remain in the development of analytical techniques for nanoplastics due to their inherent ultra-small size and ubiquitous shapes. Here, a simple technique is reported based on surface enhanced Raman spectroscopy (SERS) and salt (NaCl) induced aggregation of gold nanoparticles that has been used to detect 100 nm diameter polystyrene (PS) beads. The gold nanoparticles (AuNPs) were synthesized and stabilized by negatively charged sodium citrate. When the PS beads present in a water sample were introduced into the solution of colloidal AuNPs, they interact to each other via hydrophobic interactions and other weak forces (i.e. hydrogen, ionic, and Van der waals forces). Upon an addition of NaCl, the negatively charged ions around the AuNPs are shielded and disturbed, resulting in their aggregation around the PS beads. As a consequence, strong SERS signal enhancement produced by the aggregated AuNPs was observed, and also demonstrated in numerical modelling. Concentrations of 100 nm PS beads as low as 1 part per million (ppm) were measured, and to the best of the author’s knowledge, this is the lowest concentration detected for nanoplastics of that size or smaller by such a simple technique that has been reported.
|Title of host publication||Quantum Sensing and Nano Electronics and Photonics XIX|
|Editors||Manijeh Razeghi, Giti A. Khodaparast, Miriam S. Vitiello|
|Number of pages||7|
|Publication status||Published - 15 Mar 2023|
|Event||SPIE OPTO 2023, Quantum Sensing and Nano Electronics and Photonics XIX - San Francisco, United States|
Duration: 28 Jan 2023 → 3 Feb 2023
|Name||Proceedings of SPIE - The International Society for Optical Engineering|
|Conference||SPIE OPTO 2023, Quantum Sensing and Nano Electronics and Photonics XIX|
|Period||28/01/23 → 3/02/23|
Bibliographical noteFunding Information:
This piece of work was carried out under an ITN project MONPLAS which received funding from the European Union's Framework Programme for Research and Innovation Horizon 2020 under the Marie Sklodowska-Curie Grant Agreement No. 860775.
© 2023 SPIE.
- gold nanoparticles