Possibilities and drawbacks of total reflection X-ray fluorescence spectrometry as a fast, simple and cost-effective technique for multielement analyses of cosmetics

Abstract

This paper shows a simple, rapid and cost-effective method for multielement analyses of cosmetics. Total reflection X-ray fluorescence spectrometry (TXRF) is used to determine the composition, particularly the presence of potentially toxic elements, of cosmetics. Three sample preparation methods based on suspension preparation were developed for different types of cosmetic samples, e.g. lipsticks, eye shadows and body creams. Limits of detection within the low mg kg-1 range were obtained and enabled cosmetic screening for compliance with the legal thresholds for some major toxic elements. A good accuracy of the results on a wide range of concentration levels (>10000 mg kg-1) was found without the need of sample dilution. Results obtained for most elements in the lipstick and cream samples agreed with those obtained by the reference method recommended by the Food and Drug Administration, based on using inductively coupled plasma techniques after microwave digestion. However, for eyeshadow analysis, a more sophisticate approach is needed to improve the analytical results.

Determination of essential elements (Mn, Fe, Cu and Zn) in herbal teas by TXRF, FAAS and ICP‐OES

“…This fact can be related with the inhomogeneity of the suspension and also the deposition of the solid sample on the reflector as it has been pointed in recent publications dealing with the solid suspension analysis by TXRF. [ 34 ] Despite of the lower precision of TXRF in comparison with FAAS and ICP‐OES methods, the TXRF method presents also some interesting advantages in the field of vegetation sample analysis including a simpler sample treatment and quantification approach as well as a reduction of measuring costs and harmful reagents (see Table 4). So, depending on the final purpose of the analysis it can be a sustainable and fast analytical alternative to the most commonly used ones involving a previous digestion of the sample and ICP‐OES or FAAS analysis.…”

An overview of the applications of total reflection X-ray fluorescence spectrometry in food, cosmetics, and pharmaceutical research

“…Usually, a single digestion step using a mixture of concentrated inorganic acids (i.e., HNO 3 , HCl, H 2 SO 4 and HClO 4 ) and an oxidant agent, such as H 2 O 2 is required. 60 In 2009, a study performed by the Food and Drug Administration (FDA)-US demonstrated the necessity of using a microwaveassisted digestion procedure for lipstick samples based on a combination of HNO 3 and HF followed by an addition of boric acid to ensure the solubility of any formed uorides. Even with aggressive sample treatments, clear digests were not obtained, and portion size effects were observed.…”

2020 atomic spectrometry update – a review of advances in X-ray fluorescence spectrometry and its special applications

“…Dhara and Misra 50 presented a comprehensive review paper on the performance and analytical procedures of TXRF spectrometry in this field. In the analysis of cosmetics, Margui et al 51 presented a simpler, more rapid and more cost-effective alternative to the commonly used ICP-AES analysis of digested samples. As there was no requirement for sample pretreatment, the analysis time was reduced and the sample size of 0.01–0.02 g was considerably lower than that needed for digestion (1 g).…”