Determining Number Concentrations and Diameters of Polystyrene Particles by Measuring the Effective Refractive Index of Colloids Using Surface Plasmon Resonance

Abstract

The capabilities of surface plasmon resonance (SPR) for characterization of colloidal particles were evaluated for 100, 300, and 460 nm nominal diameter polystyrene (PS) latexes. First the accuracy of measuring the effective refractive index (n) of turbid colloids using SPR was quantified. It was concluded that for submicrometer sized PS particles the accuracy is limited by the reproducibility between replicate injections of samples. An SPR method was developed for obtaining the particle mean diameter (d) and the particle number concentration (c) by fitting the measured n of polystyrene (PS) colloids diluted in series with theoretical values calculated using the coherent scattering theory (CST). The d and c determined using SPR agreed with reference values obtained from size distributions measured by scanning electron microscopy (SEM), and the mass concentrations stated by the manufacturer. The 100 nm particles adsorbed on the sensing surface, which hampered the analysis. Once the adsorption problem has been overcome, the developed SPR method has potential to become a versatile tool for characterization of colloidal particles. In particular, SPR could form the basis of rapid and accurate methods for measuring the c of submicrometer particles in dispersion.

Determination of the Distance Between the Cytochrome and Dehydrogenase Domains of Immobilized Cellobiose Dehydrogenase by Using Surface Plasmon Resonance with a Center of Mass Based Model

“…Developing new models for SPR data analysis is therefore the prime vehicle for conquering new areas of application. For instance, the authors have in earlier publications used coherent scattering theory that gives the effective refractive index of particle dispersions for extracting the concentrations and mean diameters of colloidal polystyrene particles . This approach was later used for measuring the frequency of neurotransmitter exocytosis events from PC12 cells cultured on the SPR surface …”

“…The effective refractive index ( n eff_sample ) of the matter within the exponentially decaying evanescent field can be calculated from the θ r using eq in ref . This equation can be approximated by a linear relation between the θ r and n eff_sample for the relatively small resonance angle shifts that are produced by a protein layer adsorbed on the sensing surface.…”

“…For instance, the authors have in earlier publications used coherent scattering theory that gives the effective refractive index of particle dispersions for extracting the concentrations and mean diameters of colloidal polystyrene particles. 29 This approach was later used for measuring the frequency of neurotransmitter exocytosis events from PC12 cells cultured on the SPR surface. 36 It was here demonstrated that interpreting SPR angle shifts upon altering the chemical environment as changes in the distance between the two CDH domains gave results that are in accordance and complement earlier electrochemical and SAXS-based studies.…”

Optical Coherent Reflection from a Confined Colloidal Film: Modeling and Experiment

“…This is particularly important because it was shown recently that from this effective RI, it is possible to infer the size and the RI of the colloidal particles. 17,18 Further tests on the CSM and the vdH's EMM should be of interest in the future for the optical reflectivity in an external reflection configuration. In principle, one should expect that in the case of dilute colloids, the CSM should give better estimates of the reflectivity than the vdH's EMM and the MG-EMM once the particles are not small compared to the wavelength.…”

Measurement of Low Concentration of Micro-Plastics by Detection of Bioaffinity-Induced Particle Retention Using Surface Plasmon Resonance Biosensors

“…Refer to Dr. Jani et al for the quantitative method of PS latexes by SPR [37]. The SPR experiments were performed on a SensiQ discovery device (ICX Nomadics, Oklahoma City, OK, USA) at 25 • C with PBS (pH 7.4) as the running buffer.…”