Optofluidic Force Induction meets Raman Spectroscopy and Inductively Coupled Plasma – Mass Spectrometry: A new hyphenated technique for comprehensive and complementary characterisations of single particles

17 October 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Nanoparticles are produced at accelerating rates, are increasingly integrated in scientific and industrial applications, and are widely discharged into the environment. Analytical techniques are required to characterise parameters such as particle number concentrations, mass and size distributions, molecular and elemental compositions as well as particle stability. This is not only relevant to investigate their utility for various industrial or medical applications and for controlling the manufacturing processes, but also to assess toxicity and environmental fate. Different analytical strategies aim to characterise certain facets of particles but are difficult to combine to provide a more comprehensive picture. In this work, we suggest the on-line hyphenation of optofluidic force induction (OF2i) with Raman spectroscopy and inductively coupled plasma-time-of-flight-mass spectrometry (ICP-ToF-MS) to harness their complementary technology-specific advantages and to promote comprehensive particle characterisations. We optically trapped individual particles on a weakly focussed vortex laser beam by aligning a microfluidic flow antiparallelly to the laser propagation direction. The position of particles in this optical trap depended on the hydrodynamic diameter and therefore enabled size calibration. Additionally, laser light scattered on particles was analysed in a single particle (SP) Raman spectroscopy set-up for the identification of particulate species and phases. Finally, particles were characterised regarding elemental composition and their distributions in mass and size using SP ICP-ToF-MS. In a proof of concept, we analysed polystyrene-based plastic and TiO2 particles, and demonstrated the opportunities provided through OF2i-Raman-SP ICP-ToF-MS as new hyphenated technique.


Single particle
optical trap


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.