Desenvolvimento de metodologia eletroanalítica para quantificação de filtros solares em cosméticos usando eletrodos modificados

In the last few years, the importance and necessity of the use of sunscreen protectors, also denominated photoprotectors, is an unquestionable reality, since they protect the skin against the ultraviolet radiation. The resolution RDC n. 47 of March, 2006 of National Sanitary Vigilance Agency (ANVISA) determines which kinds of filters can be used in personal hygiene products, cosmetics and perfumes, as well as their maximal allowed concentration (10% benzophenone-3 – BZ-3, 4% to camphor 4-metylbenzilidene – MBC and 10% to 2-ethylhexyl-4-methoxycinnamate – OMC). Therefore, the present work has as objective the development of an electroanalytical method utilizing modified electrodes and square wave voltammetry to quantify BZ-3, MBC and OMC in sunscreen protector samples. The electrode composition, work electrode and voltammetric technique were optimized. The electrochemical system consisted of a cell with three electrodes: work – gold electrode modified with mercury film, reference – Ag/AgCl(sat) and auxiliary – platinum, using as electrolyte 4.0 mL of Britton Robinson Buffer 0.04 mol.L-1 (pH = 4.0), 1.0 mL of methanol (HPLC degree) and 5.50 x 10-4 mol.L-1 of cetyltrimethylammonium bromide. The electrochemical measurements were realized by square wave voltammetry, being the electrochemical system under an argon purge for 12 minutes before the analyses. The detection (LD) and quantification (LQ) limits were 0.47 mg.L-1 and 1.56 mg.L-1 to BZ-3, 0.77 mg.L-1 and 2.58 mg.L-1 to MBC and 0.78 mg.L-1 and 2.59 mg.L-1 to OMC. The method showed recovery values between 83.3 and 98.1%. Concentration values found were 3.49% m/m (728 mg.L-1) to BZ-3, 0.56% m/m (113 mg.L-1) to MBC and 0.99% m/m (208 mg.L-1) to OMC. The sunscreen protector samples were evaluated by high performance liquid chromatography, as the reference method, demonstrating a good correlation between the results. In this way, all the values are below of that allowed by ANVISA.A importância e a necessidade do uso de protetores solares, também denominados fotoprotetores, nos últimos anos, é uma realidade inquestionável, visto que protegem a pele contra a radiação ultravioleta. A resolução RDC nº 47 de março de 2006 da Agência Nacional de Vigilância Sanitária (ANVISA) determina quais tipos de filtros podem ser usados em produtos de higiene pessoal, cosméticos e perfumes, bem como sua concentração máxima permitida (10 % para benzofenona-3 - BZ-3, 4 % para 4-metilbenzilideno cânfora – MBC e 10 % para 4-metoxicinamato-2-etilhexila – OMC). Portanto, o presente trabalho teve como objetivo o desenvolvimento de um método eletroanalítico utilizando eletrodos modificados e voltametria de onda quadrada para quantificar BZ-3, MBC e OMC em amostras de protetor solar. Foram otimizadas a composição do eletrólito, eletrodo de trabalho e a técnica voltamétrica aplicada. O sistema eletroquímico consistiu em uma célula com três eletrodos: trabalho – eletrodo de ouro modificado com filme de mercúrio, referência – Ag/AgCl(sat) e auxiliar - platina, como eletrólito foi usado 4,0 mL de Tampão Britton Robinson 0,04 mol.L-1 (pH = 4,0), 1,0 mL de Metanol (grau HPLC) e 5,50 x 10-4 mol.L-1 de brometo de cetiltrimetilamônio. As medidas eletroquímicas foram realizadas por voltametria de onda quadrada, sendo o sistema eletroquímico submetido a purga com argônio por 12 minutos antes das análises. Os limites de detecção (LD) e quantificação (LQ) foram 0,47 mg.L-1 e 1,56 mg.L-1 para BZ-3, 0,77 mg.L-1 e 2,58 mg.L-1 para MBC e 0,78 mg.L-1 e 2,59 mg.L-1 para OMC. O método mostrou valores de recuperação entre 83,3 a 98,1 %. Foram encontrados valores de concentração para BZ-3 de 3,49 % m/m (728 mg.L-1), para MBC de 0,56 % m/m (113 mg.L-1) e para OMC 0,99 % m/m (208 mg.L-1). As amostras de protetor solar foram avaliadas por cromatografia líquida de alta eficiência, como método de referência, demostrando uma boa correlação entre os resultados. Desta forma, todos os valores estão abaixo do permitido pela ANVISA

CO2 Vertical Profiles on Four Sites over Amazon from 2019 to 2020

To improve diagnosis of Amazonia's carbon cycle, we present a 2 year data (2019 to 2020), complementary to our previosly 9 years (2010 to 2018) observations of lower troposphere CO2 concentrations performed regularly at four aircraft vertical profiling sites spread over the Brazilian Amazonia (Gatti et al., 2021). The four sites from the CARBAM project at Amazonia: SAN (2.86S 54.95W); ALF (8.80S 56.75W); RBA (9.38S 67.62W) and TEF (3.39S 65.6W), started in 2013. The sampling period was typically twice per month (Gatti et al., 2021; Gatti et al., 2014; Basso et al., 2016; Miller et al., 2007; d'Amelio et al., 2009; Domingues et al., 2020). From 2019 to 2020, a total of 141 vertical profiles from 4420 m to 300 m asl. was performed at the 4 sites. The vertical profiles were usually taken between 12:00 and 13:00 local time. Air is sampled by semi-automatic filling of 0.7 L boro-silicate flasks inside purpose-built suitcases (PFP -Programmable Flask Package) (Tans et al., 1996); there are two versions, one with 17 flasks at SAN, and another with 12 flasks at TEF, ALF and RBA. This suitcase is connected to a compressor package (PCP –Portable Compressor Package), containing batteries and 2 compressors, which is connected to an air inlet on the outside of the aircraft at wing or window, depending on the aircraft model. Once a PFP (i.e. one vertical profile) has been filled with air the PFP is transported to the INPE/ LaGEE(Instituto Nacional de Pesquisas Espaciais/Greenhouse Gases Laboratory), in Sao Jose dos Campos, Sao Paulo state, Brazil. This laboratory is a replica of the NOAA/ESRL/GMD trace gas analysis system at Boulder, Colorado, USA, and was constructed in 2003 and sent to IPEN where started the analysis in 2004.Air samples were analysed with a non-dispersive infrared (NDIR) analyser for CO2. To ensure the accuracy, we construct a calibration curve every 2 samples. The calibration curve constructed with 3-standards concentrations, produced by NOAA/ESRL/GMD. The “High” (10 ppm higher than medium), “medium” (similar to mean CO2 concentration founded in Amazonia), and “Low” (10 ppm lower than medium). We have an intercomparison program with NOAA at Natal site (5S, 35W, located at Brazilian northeast coast) where the comparison IPEN/INPE-NOAA was -0.05 ± 0.38ppm. The precision is analysed based on CO2mole fraction from “target tanks” (calibrated CO2in air in high pressure cylinders treated as unknowns by NOAA) and demonstrated long-term repeatability of 0.03ppm and a difference between measured and calibrated values of 0.03 ppm. Additional information can be shared from the LaGEE/INPE group as temperature, precipitation, and others parameters used by the group for the Nature paper entitled “Decrease in Amazonia carbon uptake linked to trends in deforestation and climate” (Gatti et al, 2021)

CH4 Aircraft Vertical Profiles Measurements at Four Amazonian Sites Between 2010 and 2018

To improve diagnosis of Amazonia's carbon cycle, starting in 2010, we initiated regular observation of lower troposphere CH4 concentrations at four aircraft vertical profiling sites spread over the Brazilian Amazonia. The four sites from the CARBAM project at Amazonia: SAN (2.86S 54.95W); ALF (8.80S 56.75W); RBA (9.38S 67.62W); TAB (5.96S 70.06W) was from 2010 to 2012 and TEF (3.39S 65.6W), started in 2013. The sampling period was typically twice per month (Gatti et al., 2014; Basso et al., 2016; Miller et al., 2007; d'Amelio et al., 2009; Domingues et al., 2020). Over nine-years, 590 vertical profiles were performed in a descending spiral profile from 4420 m to 300 m a.s.l. A mean of 75 vertical profiles was performed per year from 2010 to 2018 at the 4 sites, except for 2015 and 2016. In 2015 the flight collection was stopped in April at all sites, returning only in November at RBA. In 2016 only RBA and ALF were measured. The vertical profiles were usually taken between 12:0 and 13:00 local time. Air is sampled by semi-automatic filling of 0.7 L boro-silicate flasks inside purpose-built suitcases (PFP -Programmable Flask Package) (Tans et al., 1996); there are two versions, one with 17 flasks at SAN, and another with 12 flasks at TAB_TEF, ALF and RBA. This suitcase is connected to a compressor package (PCP –Portable Compressor Package), containing batteries and 2 compressors, which is connected to an air inlet on the outside of the aircraft at wing or window, depending on the aircraft model. Once a PFP (i.e. one vertical profile) has been filled with air the PFP is transported (from 2010 to 2014) to the IPEN (Instituto de Pesquisas Energéticas e Nucleares) Atmospheric Chemistry Laboratory in Sao Paulo, Brazil and since 2015 to the INPE/ LaGEE(Instituto Nacional de Pesquisas Espaciais/Greenhouse Gases Laboratory), in Sao Jose dos Campos, Sao Paulo state, Brazil. This laboratory is a replica of the NOAA/ESRL/GMD trace gas analysis system at Boulder, Colorado, USA, and was constructed in 2003 and sent to IPEN where started the analysis in 2004. The CH 4 analysis system is an FID (Flame Ionization Detector) chromatography (HP6890 Plus+ model) with pre-column of 198 cm of length and 3/16” o.d. (Silica Gel 80/100 mesh), a column of 106 cm of length and 3/16” o.d. (Molecular Sieve 5A 80/100 mesh), and a 12 mL volume sample loop (see Basso et al. 2016 for a detailed description). In order to assess the accuracy and long-term repeatability of the CH4 measurements, a previously calibrated sample is measured as an unknown in the system regularly. These results indicate long-term repeatability (one sigma) of 1.0 ppb. An inter-comparison between INPE and NOAA of weekly measurements at NAT (Brazilian northeast coast site) had a mean difference of 0.24±2.67 ppb (r = 0.98)

CO2 Vertical Profiles on Four Sites over Amazon from 2010 to 2018

To improve diagnosis of Amazonia's carbon cycle, starting in 2010, we initiated regular observation of lower troposphere CO2 concentrations at four aircraft vertical profiling sites spread over the Brazilian Amazonia. The four sites from the CARBAM project at Amazonia: SAN (2.86S 54.95W); ALF (8.80S 56.75W); RBA (9.38S 67.62W); TAB (5.96S 70.06W) was from 2010 to 2012 and TEF (3.39S 65.6W), started in 2013. The sampling period was typically twice per month (Gatti et al., 2014; Basso et al., 2016; Miller et al., 2007; d'Amelio et al., 2009; Domingues et al., 2020). Over nine-years, 590 vertical profiles were performed in a descending spiral profile from 4420 m to 300 m a.s.l. A mean of 75 vertical profiles was performed per year from 2010 to 2018 at the 4 sites, except for 2015 and 2016. In 2015 the flight collection was stopped in April at all sites, returning only in November at RBA. In 2016 only RBA and ALF were measured. The vertical profiles were usually taken between 12:0 and 13:00 local time. Air is sampled by semi-automatic filling of 0.7 L boro-silicate flasks inside purpose-built suitcases (PFP -Programmable Flask Package) (Tans et al., 1996); there are two versions, one with 17flasks at SAN, and another with 12 flasks at TAB_TEF, ALF and RBA. This suitcase is connected to a compressor package (PCP –Portable Compressor Package), containing batteries and 2 compressors, which is connected to an air inlet on the outside of the aircraft at wing or window, depending on the aircraft model. Once a PFP (i.e. one vertical profile) has been filled with air the PFP is transported (from 2010 to 2014) to the IPEN (Instituto de Pesquisas Energéticas e Nucleares) Atmospheric Chemistry Laboratory in Sao Paulo, Brazil and since 2015 to the INPE/ LaGEE(Instituto Nacional de Pesquisas Espaciais/Greenhouse Gases Laboratory), in Sao Jose dos Campos, Sao Paulo state, Brazil. This laboratory is a replica of the NOAA/ESRL/GMD trace gas analysis system at Boulder, Colorado, USA, and was constructed in 2003 and sent to IPEN where started the analysis in 2004.Air samples were analysed with a non-dispersive infrared (NDIR) analyser for CO2. To ensure the accuracy, we construct a calibration curve every 2 samples. The calibration curve constructed with 3-standards concentrations, produced by NOAA/ESRL/GMD. The “High” (10 ppm higher than medium), “medium” (similar to mean CO2 concentration founded in Amazonia), and “Low” (10 ppm lower than medium). We have an intercomparison program with NOAA at Natal site (5S, 35W, located at Brazilian northeast coast) where the comparison IPEN/INPE-NOAA was -0.05 ± 0.38ppm. The precision is analysed based on CO2mole fraction from “target tanks” (calibrated CO2in air in high pressure cylinders treated as unknowns by NOAA) and demonstrated long-term repeatability of 0.03ppm and a difference between measured and calibrated values of 0.03 ppm. Additional information can be shared from the LaGEE/INPE group as temperature, precipitation, and others parameters used by the group for the Nature paper entitled “Decrease in Amazonia carbon uptake linked to trends in deforestation and climate” (Gatti et al, 2021)