Banca de DEFESA: DAYARA VIRGÍNIA LINO ÁVILA
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.DISCENTE : DAYARA VIRGÍNIA LINO ÁVILA
DATA : 31/07/2020
HORA: 09:00
LOCAL: Web conferência
TÍTULO:
Determination of the total concentration and bioavailable fractions of inorganic constituents in modeling clay samples, gouache / tempera paints and plastic toys using chemometric tools and atomic spectrometry
PALAVRAS-CHAVES:
Toys; modeling clay; gouache / tempera paints; plastic toys; bioavailability; ICP OES; ICP-MS; MSFIA-HG-AFS; Chemometric Tools; Legislation.
PÁGINAS: 198
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Análise de Traços e Química Ambiental
RESUMO:
Three works were developed as analytical strategies for toy analysis, with the purpose of determining inorganic constituents in modeling clay, gouache / tempering paints and plastic toys samples, in addition to determining the bioavailable fraction of the chemical elements in this toys employing atomic spectrometry. In the first work, experimental design were applied to optimise the conditions of microwave-assisted sample digestion by analysis of toy samples. Methods based on inductively coupled plasma (ICP) were used to determine the concentrations of 22 elements in children's modeling clay. The limits of quantification (LoQ) obtained varied between 0.30 mg kg-1 (Cu) and 0.54 g kg-1 (Ca) using inductively coupled plasma optical emission spectrometry (ICP OES) and between 0.003 mg kg-1 ( Cd, Co, S and V) and 0.26 mg kg-1 (Se) by inductively coupled plasma mass spectrometry (ICP-MS). The evaluation of the reliability of the method was confirmed through by analysis of certified reference materials of oyster tissue (NIST 1566b), rice flour (NIST 1568b), peach leaves (NIST 1547) and tomato leaves (NIST1573a), as well as applying addition and recovery tests at five concentration levels. The concentrations obtained varied between <1.9 and 55.18 ± 2.38 mg kg-1 (Ba), <0.54 and 0.93 ± 0.24 g kg-1 (Ca), <0.30 and 94.95 ± 3.62 mg kg-1 (Cu), <0.14 and 13.48 ± 0.07 g kg-1 (K), <0.003 and 15.24 ± 0.44 g kg-1 ( Mg), <0.03 and 19.23 ± 1.17 g kg-1 (Na), <0.030 and 1.97 ± 0.06 g kg-1 (P), <0.10 and 8.22 ± 0.31 g kg-1 (S), <133 mg kg-1 and 11.04 ± 3.00 g kg-1 (Al) and <0.53 mg kg-1 and 1.59 ± 0.30 g kg-1 (Fe), for elements determined by ICP OES and between <0.005 and 3.35 ± 0.75 mg kg-1 (V), <0.03 and 9.33 ± 0.65 mg kg- 1 (Cr), <0.03 and 0.650 ± 0.113 mg kg-1 (Co), <0.03 and 19.06 ± 4.92 mg kg-1 (Ni), <0.18 and 28.62 ± 3.64 mg kg-1 (Zn), <0.03 and 1.06 ± 0.21 mg kg-1 (As), <0.25 and 383.73 ± 18.89 mg kg-1 (Mn) , <0.26 and 0.53 ± 0.04 mg kg-1 (Se), 0.91 ± 0.38 and 334.17 ± 37.52 mg kg-1 (Sr), <0.003 and 0.32 ± 0.06 mg kg-1 (Cd), <0.003 and 0.06 ± 0.02 mg kg-1 (Sb) and from <0.010 and 7.55 ± 0.86 mg kg-1 (Pb), for the chemical elements determined by ICP-MS. In the second work, the determination of the total concentrations and bioavailable fractions of As and Sb in gouache / tempering children's paints samples type was carried out using the analysis by injection in multi-syringe flow coupled to hydride generation atomic fluorescence spectrometry (MSFIA- HG-AFS). For As and Sb determinations, NaBH4, KI and HCl concentrations were evaluated as factors. The optimization was performed through the Doehlert design, with the intensities of total As and Sb as multiple response. The LoQ were 14.38 ng g-1 for As and 8.56 ng g-1 for Sb. For the determination of bioavailable concentrations, the LoQ were 16.21 ng g-1 for As and 7.08 ng g-1 for Sb. The precision and accuracy of the analytical method was confirmed through by analysis of certified reference materials of clay (CRM 052, Loamy Clay 1, Sigma Aldrich, USA), and river water (River Water, SLRS-4, National Research Council, Canada) and through addition and recovery tests. The analytical method was applied to twenty samples of gouache / tempering paints, in which As concentrations varied between <LoQ (<14 ng g-1) and 136.0 ± 1.1 ng g-1, and the concentrations of Sb varied between <LoQ (<8.6 ng g-1) and 74.0 ± 5.4 ng g-1. For the determination of bioavailable fractions, the procedure was applied to eight paint samples, in which for all samples the concentrations of As (<16.2 ng g-1) and Sb (<7.1 ng g-1) were below than LoQ. Finally, in the third work, a Doehlert design was employed to optimize the conditions by microwave-assisted digeston of the plastic toy samples for determination of of As, Cd, Co, Cr, Cu, Mn, Ni Pb and Sb by ICP OES and MSFIA-HG-AFS. The procedure was validated through by analysis of CRM clay (CRM 052, Loamy clay) and through addition and recovery tests. The LoQ varied between 0.03 mg kg-1 (Cd and Mn) and 0.7 mg kg-1 (Sb). The concentrations found varied between <LoQ (0.3 mg kg-1) for As; 0.21 ± 0.01 and 0.71 ± 0.04 mg kg-1 for Cd; 0.15 ± 0.02 and 1.16 ± 0.02 mg kg-1 for Co; 0.37 ± 0.03 and 9.42 ± 0.20 mg kg-1 for Cr; 1.67 ± 0.11 and 26.44 ± 0.28 mg kg-1 for Cu; 0.51 ± 0.04 and 21.18 ± 0.36 mg kg-1 for Mn; 0.56 ± 0.06 and 2.90 ± 0.15 mg kg-1 for Ni; 0.46 ± 0.10 and 37.46 ± 3.00 mg kg-1 for Pb; 0.84 ± 0.06 and 32.81 ± 2.04 mg kg-1 for Sb.
MEMBROS DA BANCA:
Presidente - 1698441 - RENNAN GEOVANNY OLIVEIRA ARAUJO
Interno - 1303987 - MARIA ELISABETE MACHADO
Interno - 268481 - SERGIO LUIS COSTA FERREIRA
Interno - 2297184 - AMALIA GEIZA GAMA PESSOA
Interno - 2721446 - DANIELE CRISTINA MUNIZ BATISTA DOS SANTOS
Interno - 282814 - MARIA DAS GRACAS ANDRADE KORN
Externo à Instituição - VICTOR CERDÀ MARTÍN
Externo à Instituição - EDUARDO SIDINEI CHAVES - UFSC
Externo à Instituição - LETÍCIA MALTA COSTA - UFMG
Externo à Instituição - ADRIANO DE ARAÚJO GOMES - UFRGS