Titanium dioxide in face powders and eyeshadows: Developing an analytical methodology for accessing customer safety.

BACKGROUND: Titanium dioxide (TiO2), a white powder, represents the opacifier used in many products, including drugs, foods, cosmetics, paints, and dyes. METHOD: The Uv-Vis spectrophotometry was a particularly suitable technique to quantify TiO2 in the solutions obtained from cosmetics. In this work, we determined the TiO2 content in a total of 88 samples of eye shadows and face powders of different brands and costs. Before to analyse the samples, we developed the mineralization and analysis method, in fact, fusion with potassium bisulphate would be very laborious because it must be carried out on one sample at a time and requires very long times, instead, the mineralization with the acid mixture and the aid of microwaves allowed us to solubilize six samples at the same time within 45 min. RESULTS: From the results obtained, we can state that the highest concentrations of TiO2 are found in the eyeshadows with a maximum value of 36% in a blue eyeshadow.

Analytical Method for Quantification of Several Phthalate Acid Esters by Gas Chromatography-Mass Spectrometry in Coffee Brew Samples.

Several phthalate acid esters (PAEs), often called phthalate esters or phthalates, are substances classified as harmful due to their carcinogenic and mutagenic properties, and moreover, as dangerous for humans because they interfere with the endocrine system. In general, phthalic esters are used as plasticizers for different polymers and more other consumer products. In the present study, we describe a simple method to quantify PAEs in coffee brew using a liquid-liquid extraction without purification processes through analysing the obtained organic phase by GCMS in the single ion monitoring mode. The totals of single PAEs, in coffee brew samples analysed by us, are in the range of 159-5305 µg L-1 . Considering that, on average, a person drinks three cups (total 90 mL) of the aforementioned drink per day, this will lead to the uptake of a total 14 to 477 µg of phthalates.

Platinum and Rhodium in Potato Samples by Using Voltammetric Techniques.

Potato is a starchy, tuberous crop from the perennial Solanum tuberosum having high nutritional values. This paper is the first analytical approach to quantify Pt and Rh in vegetal food. In this study a total of 38 different potato samples produced in Europe and one in Australia were investigated. Determinations of Pt and Rh in potato samples were carried out by Differential pulse voltammetry (DPV/a) for platinum and by Adsorptive stripping voltammetry (AdSV) for Rh using standard addition procedure. Because no certified reference potatoes containing platinum and rhodium are available, we used addition standard method. The quantification limits for Pt and Rh are 0.007 and 0.0008 µg kg-1 respectively. Considering all the potato samples, concentrations of Pt and Rh vary in the ranges from 0.007 to 109 µg kg-1 (sample no, 6 potatoes grown in Sicily) and from 0.0008 to 0.030 µg kg-1 (sample no. 3 of potatoes grown in Emilia Romagna), respectively. For both metals, in many cases the concentrations fall near the quantification limit. In all the samples, platinum is always more abundant than rhodium and their mean ratio is 14,500, which is much greater than that of the Earth's crust (about 100).

Speciation of vanadium in urban, industrial and volcanic soils by a modified Tessier method.

Vanadium (V) concentrations in industrial, urban and volcanic soils were sequentially extracted using a modified Tessier's method. The voltammetric technique was used to determine V concentrations in solutions obtained from the various extraction steps. At the reference stations, the V concentrations (sum of four individual fractions) in soils ranged from 0.72 to 0.24 g kg(-1) dry weight (d.w.) with a mean value of 0.18 g kg(-1) d.w. V concentrations in soils of the Palermo urban area ranged from 0.34 to 2.1 g kg(-1) d.w., in the Milazzo (industrial) area between 0.26 and 5.4 g kg(-1) d.w. and in the volcanic area near Mt. Etna from 0.91 to 2.9 g kg(-1) d.w. When the V concentrations around Mt. Etna were compared with those obtained at the reference stations, it was confirmed that Mt. Etna is a continuous source of V. In all the samples analyzed, the majority of V (from 94 to 100%) was detected in the fourth fraction.

Discrimination of almonds (Prunus dulcis) geographical origin by minerals and fatty acids profiling.

Twenty-one almond samples from three different geographical origins (Sicily, Spain and California) were investigated by determining minerals and fatty acids compositions. Data were used to discriminate by chemometry almond origin by linear discriminant analysis. With respect to previous PCA profiling studies, this work provides a simpler analytical protocol for the identification of almonds geographical origin. Classification by using mineral contents data only was correct in 77% of the samples, while, by using fatty acid profiles, the percentages of samples correctly classified reached 82%. The coupling of mineral contents and fatty acid profiles lead to an increased efficiency of the classification with 87% of samples correctly classified.

Platinum and rhodium associated with the leaves of Nerium oleander L.; analytical method using voltammetry; assessment of air quality in the Palermo (Italy) area.

A rapid accumulation of the catalytic active noble metals in the environmental and biological matrices was observed and concern arose about potential environmental and health risks. The development of reliable analytic methods to measure very low Pt and Rh concentrations is required. The main purpose of this work was to develop a reliable method for the determination of Pt and Rh in environmental matrices because of inherent difficulties in using conventional techniques used, in particular, the ICP-OES technique. A direct determination of Pt using ICP-MS, for instance, is problematic, due to interfering signals. In this work, differential pulse voltammetry (DPV/a) and adsorptive stripping voltammetry (AdSV) were used for the determination of Pt and Rh in Nerium oleander leaves. Pt and Rh concentrations were found in the ranges 0.33-25 and 0.40-4.6 microg/kg d.w., respectively. We carried out linear regression analysis between total PAH concentrations in leaves of oleander and of Quercus ilex measured in previous researches and the data obtained in this work. The high correlation coefficients were obtained; which demonstrates that oleander leaves can be used to establish the presence and the distribution of pollutants in a chosen area.

The formal redox potential of the Ti(IV, III) couple at 25 degrees C in 1 M HCl 2 M NaCl medium.

The formal redox potential of the Ti(IV, III) couple has been determined at 25 degrees C in 1 M HCl, 2 M NaCl aqueous medium, by emf measurements of a junction-free cell with glass and mercury electrodes. Ti(III) and Ti(IV) concentrations were changed by controlled electrolysis. The mean value of the searched formal potential, in a large range of total titanium concentration, is 9 +/- 1 mV against the molar hydrogen electrode in the same ionic medium.

The formal redox potential of the Yb(III, II) couple at 0 degrees C in 3.22 molal Nacl medium.

Following our previous investigations on aqueous solutions of hypooxidized and iperoxidized species, we managed, by lowering the temperature of the solutions to 0 degrees C, to obtain, by electrochemical methods, Yb(II) and Yb(III) mixtures, enough stable to determine by a potentiometric method the formal redox potential of the Yb(IlI, II) couple. Its value, in a large range of total Ytterbium concentration, is -1233 +/- 3 mV against the molal hydrogen electrode in the 3.22 m NaCl medium.