Characterization and Determination of Selenium Nanoparticles in Dietary Supplements by Single Particle Inductively Coupled Plasma Mass Spectrometry

Abstract

A single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) method was developed for the determination and characterization of selenium nanoparticles (SeNPs) in dietary supplements in syrup formulations containing selenium dioxide and ascorbic acid. Experimental parameters affecting the signal intensities of the SeNPs, such as torch distance, sample flow rate, and addition of organic solvent, were optimized. It was observed that adding 3.0% (v/v) of propan-2-ol to the solutions increased the selenium nanoparticle signal by 3.4 times. SeNPs were detected in all of the five dietary supplements studied, and it was found that 19.3–60.4% of the total selenium was in the form of nanoparticles and that their mean diameters were in the range of 50–130 nm. Under the optimized conditions, the limit of detection for nanoparticle number concentration (LOD_conc) and the limit of detection for nanoparticle size (LOD_size) of the proposed SP-ICP-MS method were 770 particle mL⁻¹ and 36 nm, respectively. The recovery of total selenium determination was in the range of 102.1–106.4%. The recovery in terms of the particle number concentration in samples spiked with 140 nm and 50 nm SeNPs was between 88.8 and 114.0%. The developed SP-ICP-MS method is sensitive, rapid, and suitable for routine applications with minimum sample preparation for the characterization and determination of SeNPs in dietary supplements.