RESUMO
An analytical methodology has been developed and validated for the purpose of identifying and quantifying four parabens (methylparaben, ethylparaben, propylparaben and n-butylparaben) in water samples. The combination of rotating disk sorptive extraction (RDSE) technology with ultra-high performance liquid chromatography (UHPLC), along with electrospray ionization source (ESI) and time of flight mass spectrometry (TOF/MS) in trap mode, allowed for eliminating derivatization processes and a reduction of the chromatographic time required, achieving a greener analytical method. In this method, detection limits and precision (%RSD) were lower than 0.018 µg L-1 and lower than 9.7% for all the parabens, respectively, being better than similar works. Matrix effect and absolute recoveries were studied in tap and sewage water samples to observe suppressions of the signals for all analytes, and absolute recoveries were around 60%. This methodology was applied to the analysis of two sewage samples (punctual and composite) obtained from locations in Santiago, Chile.
Assuntos
Parabenos/análise , Esgotos/química , Poluentes Químicos da Água/química , Chile , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Estrutura Molecular , Fatores de TempoRESUMO
A combination of rotating disk sorptive extraction (RDSE) using Oasis® HLB as the sorbent phase and gas chromatography mass spectrometry (GC-MS) has been performed for the determination of four of the most widely used parabens: methylparaben, ethylparaben, propylparaben and n-butylparaben. The extraction and derivatization of the analytes in water samples were optimized by using factorial (screening) and Doehlert designs, thus reducing the number of analyses with the concomitant reduction of time, reagents, waste, samples and cost. Thus, a RDSE method using 20mL of sample was performed. The disk was rotated at 2900rpm for 70min at room temperature. After a desorption step and evaporation of solvent, a derivatization method using 5µL of N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) for 15min at room temperature was used previously to inject the final extract into GC-MS. The detection limits and precision (%RSD) were lower than 0.05µgL- 1 and 9.7% for the studied compounds, respectively. Recoveries were studied using effluent samples of a wastewater treatment plant (WWTP), with values higher than 80% being obtained. The applicability and reliability of this methodology were confirmed through the analysis of tap water and influents from Santiago, Chile, with concentration values ranging from 0.57 to 0.83µgL- 1 in influents. The main advantage of the present RDSE method is that it is significantly faster than its counterpart by SBSE and requires a considerable lower volume of derivatizing agent.
Assuntos
Parabenos/análise , Poluentes Químicos da Água/análise , Acetamidas/química , Adsorção , Chile , Monitoramento Ambiental , Fluoracetatos/química , Cromatografia Gasosa-Espectrometria de Massas , Parabenos/química , Compostos de Trimetilsilil/química , Águas Residuárias/análise , Poluentes Químicos da Água/químicaRESUMO
Se presenta un caso de granuloma elastolítico a células gigantes, dermatosis recién individualizada y con características clínicas e histopatológicas bién definidas