Analytical Method Validation for the Identification and Quantification of Dissolved Gold and Gold Nanoparticles in Cosmetics Products by Single Particle Inductively Coupled Plasma Mass Spectrometry

Abstract

Nanoparticle (NP) applications have recently gained more space in the development of many products, especially in cosmetology. The aim of the present study was to validate a single particle inductively coupled plasma mass spectrometry technique for the detection and quantification of gold nanoparticles (AuNPs) and gold ions (Au (i)) in different cosmetics currently marketed in Brazil. The size limit of detection for pure AuNPs was 22 nm, and a concentration limit of detection of 2.3×106 particles g−1 was achieved. The limit of detection for total gold was 0.02 µg L−1 obtained in standard mode conditions. The recovery achieved was 98% for dissolved Au and 109% for AuNPs; the relative standard deviation was <5%. This validated method was applied to cosmetic products (n = 10) from different national and international industrial producers. Most cosmetics analysed contained quantifiable amounts of dissolved gold (< 0.005-2.1 µg g−1) and only four contained quantifiable amounts AuNPs the variability of the results detected (< LOD – 9.3 × 108 particles g−1). The products that contained the greatest amount of these metallic NPs were the artisanal products. The results demonstrate the importance of adequate quality control for cosmetics to ensure consumer safety

Development of the methodology for the Detection and Quantification of Zinc Oxide Nanoparticles and dissolved Zinc by Single-Particle Inductively Coupled Plasma Mass Spectrometry

“…Through the results obtained, the Snedecor F-test of homogeneity of variances and Student's t-test for comparison of means were applied. The t-test value was bellow of the the expected value (t critic) and it indicates that the matrix does not have a statistically signi cant effect on the results with a 95% con dence (p-value > 0,05%) (25,31).…”

“…In the ICP-MS technique, only a fraction of the nebulized suspension effectively reaches the plasma (1-15%) when using conventional systems, and this, too, happens in the single particle mode (24). The precise determination of this fraction, de ned as transport e ciency (TE), is critical for correctly determining both particle number concentration and size (25). The TE was calculated by the particle frequency (TEF) methods using an AuNP standard solution of nominal size of 50 nm, which was sonicated for 1 min and diluted 100-fold in deionized water (Milli-Q Advantage, Molsheim, France) to a nal nominal concentration of 1 × 10 5 particles mL -1 , supplied by NanoComposix (San Diego, CA, USA).…”

“…The selectivity of the technique was determined by matrix effect (standard addition). Two distinct groups containing Zn ions were prepared, a group of the matrix of interest (group 1) with known concentration of the analyte, and another group made up of water and the analyte (group 2) (25).…”