COSMETIC PRODUCTS FOR CHILDREN AND ADULTS – DETERMINATION OF As, Ni, Pb AND Zn CONTENTS

59 A matéria publicada nesse periódico é licenciada sob forma de uma Licença Creative Commons – Atribuição 4.0 Internacional http://creativecommons.org/licenses/by/4.0/ COSMETIC PRODUCTS FOR CHILDREN AND ADULTS – DETERMINATION OF As, Ni, Pb AND Zn CONTENTS Alessandra Mocellin Zapp Popowiczk1, Larissa Macedo dos Santos-Tonial1* 1Departamento Acadêmico de Química, Universidade Tecnológica Federal do Paraná, Via do Conhecimento, km 1, Bairro Fraron, Pato Branco, PR, Brasil. *E-mail: larissasantos@utfpr.edu.br Recebido em: 19/08/2020 Aceito em:21/12/2020 DOI: 10.17058/tecnolog.v25i1.15792 ____________________________________________________________________________________________________________ ABSTRACT The objective of this work was to determine the concentration of potentially toxic elements in different cosmetic products, using simple and accessible digestion methodologies, and spectroscopic techniques. A total of twelve products were selected, purchased and analyzed, which include blush (BL), eye shadow (SH), face powder (PO) and powdered paint for children (PP). The samples were dried (at 100oC), crushed and homogenized. Two methodologies were used for digestion. The contents of Ni, Pb and Zn were quantified by atomic absorption spectrometry flame (FAAS), and the contents of As by atomic absorption spectrometry with electrothermal atomization in a graphite oven (GFAAS). In general, the samples showed contents below the detection limit (LOD) for Ni, Pb, As and Zn. However, some PP samples showed Zn contents between 2 ± 1 and 442 ± 32 mg L-1. This result is probably due to the use of some natural or inorganic pigments, and suggests the following actions: (1) regular monitoring of potentially toxic elements in PP products; (2) new studies on Zn levels in cosmetic products for children; and (3) the creation of legislation to regulate the composition of PP products.


Reagents and Solutions
Standard solutions for calibration curves were prepared by serial dilution of commercial stock solutions (1000 mg L −1 ) of Grupo Química. The reagents HNO3 and H2O2 were of analytical grade unless otherwise specified. Ultra-pure water (18MΩ) was obtained from a Milli-Q purification system (Merk Millipore, Darmstadt, Germany). A Digital Ultrasonic Cleaner CD-4860 ultrasonic bath (Gnatus, São Paulo, Brazil) was used to sample sonication in methodology 2. All laboratory glassware was previously decontaminated with 10% (v v -1 ) of HNO3 A matéria publicada nesse periódico é licenciada sob forma de uma Licença Creative Commons -Atribuição 4.0 Internacional http://creativecommons.org/licenses/by/4.0/ solution for 24 hours. Before use, these materials were rinsed abundantly with deionized water.

Sample Preparation
Initially, the cosmetic samples were dried (at 100 o C), until you get constant weight, grounded and homogenized. For sample digestion, two methodologies were applied. The methodology 1 used in this study was based on procedures recommended by Ullah et al [16] with some modifications, and the methodology 2 is a suggestion of this work.
Methodology 1 -After drying (at 100 o C) the cosmetic sample was calcined at 600ºC for 2 hours [11]. After cooling to room temperature (at desiccator), the residual ashes (≈0.100 g) were digested with 2mL of HNO3 1 mol L -1 at 130 o C in a digester block to about 1mL. Finally, the solution was quantitatively transferred to Falcon tubes and the volumes completed with ultra-pure water (MiliQ) up to 25mL [14]. All experiment was carried out in triplicate (n = 3). Blank was treated in the same procedure. The solution obtained after digestion was used for analytical determinations, which were carried out in triplicate.

Detection and Quantification Limits
The limits of detection (LOD) and quantification (LOQ) were calculated following the IUPAC approach [15], which consists in analyzing the blank sample, calculating the standard deviation and expressing the result as the mean plus 3-and 10times standard deviation for LOD and LOQ, respectively: where SD is the standard deviation for ten blank measurements (using an empty platform) and b is the angular coefficient of the calibration curve.

Moisture and Ashes Content Determination
After drying at 100 o C, the cosmetic sample was calcined in a muffle oven at 600 o C for 2 hours. Subsequently, the calcined sample was cooled in a desiccator. Finally, the mass of the sample was measured, and the moisture content (MC) and the ashes content (AC) were calculated using the formulas: where MC is the moisture content of the sample, Mwet is the wet weight and Mdry is the dry weight.

Instrumental Parameters
The inorganic elements may exist as impurities in the raw ingredients or as products of the manufacturing process of cosmetics [18]. Among the harmful elements that elicit concern are include Ni, [19] Pb, As, [20] and Zn [18][19][20][21].
The Ni, Pb, and As are naturally present in iron oxide pigments and other raw materials used in the cosmetic products A matéria publicada nesse periódico é licenciada sob forma de uma Licença Creative Commons -Atribuição 4.0 Internacional http://creativecommons.org/licenses/by/4.0/ during the manufacturing [7,22]. Although, currently there is no regulation on the tolerances of the toxic elements in iron oxide pigment, the quantification of the Pb, As, and Ni contents in cosmetic products are of great importance for the control of its quality and for the safety of its applications [22]. Table 3. Results obtained (mg L -1 ) in the determination of Ni, Pb, Zn and As in cosmetic products by two methodologies and employing the FAAS and GFAAS. The focus of this study is on elements with known significant toxicological properties such as Ni, Pb, and As. Also, the Zn is an essential element, and at high levels may cause adverse effects on human health in cosmetic products. According to da Costa et al. [12], Zn is an essential micronutrient and its toxicity is rare it can be easily found in facial cosmetics in the form of oxides [12], commonly employed in cosmetics for blocking ultraviolet light or coloring pigments [21]. The cosmetic samples presented Ni, Pb, and As concentration below the LOD (Table 3). Similar to the results obtained for Ni were observed to Pb and As. In Table 3  [23] to eye shadows from China, Italy, and USA using a FAAS.
The Pb potentially affects almost every system, such as the reproductive, neurological, hematopoietic, hepatic, and renal systems in the human body. The Pb can even cause cancer due to excessive accumulation in the human body [25]. Exposure to As can cause a variety of diseases, including skin lesions, neurological and respiratory effects, atherosclerosis, and several types of cancer [26]. The high concentrations of Zn in some of the PP samples are probably due to the use of Zn oxide, an inorganic pigment [10]. The Zn oxide is a white pigment commonly employed in cosmetic formulations. The white pigments are required for skin protection during cosmetic use [27], and to block ultraviolet radiation [21]. Others substances, such as titanium dioxide can be used with the same function [27]. In PPO samples, values below the LOD may be associated with the use of another ingredient with the same function as Zn oxide. The powdered blushes do not contain much Zn oxide [28], in other words, this affirmation corroborate with the results presented in Table 3. However, there is a lack of standardization between them around the world. In some cases, the limits are established based on the concentrations of elements commonly found in cosmetics sold in each country [3].
In Brazil, the Agência Nacional de Vigilância Sanitária (ANVISA) is responsible for the marketing authorization of cosmetics, and supervises and establishes standards for manufacturers, checking the production process, in addition to regularly publish a list of irregular cosmetic products [29][30][31][32][33].
The ANVISA also provides the national limits of chemical elements in cosmetic products. However, there is no specific legislation for children's cosmetics, such as PP. The methodology proposed in this study (methodology 2) was compared with some methodologies applied in the cosmetic digestion [11,20,37]. The methodology proposed to the consumers a lower volume of reagents, generate less waste volume, does not use reagent with high hazard (HF), and employs equipment for easy acquisition and maintenance, such as ultrasonic bath and digester block.

Moisture and Ashes Content Determination
In Figure 1 are presented the moisture and ashes content in BL, SH, PO and PP samples. compositions. According to Atz and Pozebon [39], the pigments more frequently used in cosmetics are in general oxides, such as iron oxide, chromium oxide, titanium dioxide, Zn oxide. The micas, aluminosilicates coated with titanium dioxide, iron oxide, or titanium dioxide, also are commonly used in the production of cosmetics because contain some pigments capable of producing pearly effects [40].
The SH is available in several colors, and pigments such as iron oxide, titanium dioxide, copper powder, and chromium oxide, which are commonly used in this cosmetic [39]. Moreover, substances such as titanium dioxide, bismuth oxychloride, and micas may be used to provide various effects to these products. PO usually uses iron oxides as the main pigment, but other inorganic pigments, such as ultramarines, chrome oxide, and chrome hydrate, also may be used [28]. The iron oxide is also a common dye in BL [11].

Conclusions
The proposed methodology consumes less energy and acid (HNO3), is faster and cheaper, and it can be performed with instruments commonly found in laboratories.
From the results obtained, Ni, As, Zn, and Pb were not detected in the BL, SH, and PO products from China, and Ni, As, and Pb were not detected in PP from Brazil.
The application of FAAS, preceded by sample preparation using the methodologies 1 and 2, has allowed the Zn quantification in PP samples. The Zn was found at concentrations between 2 ± 1 mg L -1 and 442 ± 32 mg L −1 .
It is important to avoid the use of cosmetic products by children. ANVISA recommends that kids use only children's products [41]. However, as the commercialization of cosmetic products for this public has grown in recent years, the following actions are recommended: (1) Regular monitoring of potentially toxic elements in PP products; (2) New studies about the Zn levels in cosmetic products for children; (3) The creation of legislation to regulate the composition of PP products.