Browsing by Author "Correa, Joane Mariela Miari"

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    Occurrence of contaminants of emerging concern in surface waters from Paraopeba river Basin in Brazil : seasonal changes and risk assessment.
    (2021) Correa, Joane Mariela Miari; Sanson, Ananda Lima; Machado, Célia de Fátima; Aquino, Sergio Francisco de; Afonso, Robson José de Cássia Franco
    This study describes the application of gas chromatography coupled to mass spectrometry (GC-MS) to evaluate the occurrence of 12 CECs—contaminants of emerging concern (bisphenol A, diclofenac, 17β-estradiol, estriol, estrone, 17α-ethinylestradiol, gemfibrozil, ibuprofen, naproxen, 4-nonylphenol, 4-octylphenol, and acetaminophen) in surface waters from Paraopeba River Basin, Minas Gerais State, Brazil. The analytical procedure was validated and applied to 60 surface water samples collected across four sampling campaigns along the upper and middle watershed. Methods for CECs determination involved sample filtration, and solid-phase extraction (SPE) with subsequent derivatization of the target compounds prior to their analysis by GC-MS. The LOQ varied from 3.6 to 14.4 ng/L and extraction recoveries ranged from 46.1 to 107.1% for the lowest spiked concentration level (10 ng/L). The results showed a profile of spatial distribution of compounds, as well as the influence of rainfall. Ibuprofen (1683.9 ng/L), bisphenol (1587.7 ng/L), and naproxen (938.4 ng/L) occurred in higher concentrations during the rainy season, whereas during the dry season, the concentrations of bisphenol (1057.7 ng/L), estriol (991.0 ng/L), and estrone (978.4 ng/L) were highlighted. The risk assessment of human exposure shows that for most contaminants, the concentration is well below the estimated thresholds for chronic toxicity from water intake. However, estradiol and 17α-ethinylestradiol showed concentrations in the same order of magnitude as the guide values estimated for babies.
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    Simultaneous quantification of amphetamines and ephedrines in urine by GC/MS using analytical-grade acetic anhydride/ayridine as derivatizing reagents : a suitable approach to reduce costs of routine analyses.
    (2009) Bergo, Patrícia Luísa de Souza; Correa, Joane Mariela Miari; Nagem, Tanus Jorge; Augusti, Rodinei; Nascentes, Clésia Cristina
    Neste trabalho foi desenvolvido e validado um método quantitativo para a análise de anfetaminas e efedrinas em urina, utilizando-se anidrido acético e piridina, ambos em grau analítico, como derivatizantes. As amostras foram extraídas por extração em fase sólida (EFS), derivatizadas e em seguida analisadas por CG-EM. O método apresentou ampla faixa linear (25-1000 ng mL-1 com R2 > 0,99), alta sensibilidade (LODs variando de 0,0140 a 15,33 ng mL-1 e LOQs variando de 0,0466 a 51,10 ng mL-1), bons índices de precisão (CV < 6% para intra- e inter-ensaios) e excelentes índices de recuperação (87-96%) para todos os compostos estudados. Após a validação, o método foi aplicado em análises de amostras reais de urina humana nas quais ao menos um dos analitos em estudo foi identificado previamente. Em todas as amostras, anfetaminas e efedrinas foram facilmente quantificadas mostrando que a associação de anidrido acético e piridina é uma boa opção como agente derivatizante.