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| Author(s): |
César Augusto Marasco Júnior
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Araraquara. 2020-12-17. |
| Institution: | Universidade Estadual Paulista (Unesp). Instituto de Química. Araraquara |
| Defense date: | 2020-11-25 |
| Advisor: | Paulo Clairmont Feitosa de Lima Gomes; Bianca Ferreira da Silva |
| Abstract | |
Pharmaceutical compounds and personal care products (PPCPs) are substances widely present in modern society. These compounds, known as emerging contaminants, are found in the environment at concentration levels ranging from ng L-1 to µg L-1. Thus, it is necessary to develop studies and analytical methods to determine psychoactive compounds, antibiotics and markers of anthropogenic activity in developing countries, such as Brazil, where sanitation conditions are still precarious, either due to the lack of wastewater treatment plants (WWTPs) and/or suitable effluents treatment. High performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) has been the technique of choice for detecting and quantifying these compounds at background concentrations (i.e., ng L-1). Due the complexity of the environmental samples, it is necessary to apply solid phase extraction (SPE) and/or restricted access media (RAM) to pre-concentrate the analytes. These approaches combined with the online method of sample preparation are an alternative to decrease cross-contamination, in addition to allowing automation and carrying out the procedure sequentially. The analytical methods developed were validated according to national and international validation guidelines using only 50 µL of injection volume in ultrapure water and lab-made sewage, being the first approach being considered for quantification due to the use of individual isotopic labeled standards. Figures of merit such as limit of detection (LOD), limit of quantification (LOQ), linearity, intra- and inter-day precision and matrix effect were evaluated. Analysis of variance (ANOVA) was applied to verify possible lack of fit. In addition, in order to verify the chromatographic efficiency, resolution (Rs) and peak asymmetry (As) were considered; carryover was also evaluated in order to ensure analysis reliability and reuse preconcentration column reusability. With analysis times of 24 min (for Waters' OASIS HLB® cartridge) and 16 min (for RAM column), the methods proved to be fast and viable alternatives for simultaneous analysis of the target compounds. The methods’ linearity proved to be suitable, since r2 > 0,99 was obtained for all compounds in ultrapure water and lab-made sewage (except for CBZ in lab-made sewage on OASIS cartridge and for FLX also in lab-made sewage on RAM column). The intra- and inter-day precision values were less than 10 and 17 %, respectively, for the OASIS cartridge and less than 5,8 and 14,1 % for the RAM column. In both methods, caffeine was the compound widely detected, reaching a maximum concentration of 715 µg L-1 in the analysis using the OASIS pre-concentration cartridge and 392 µg L-1 in the analysis using the RAM column. A simple and informative exploratory strategy applied to the analysis of environmental exposure chemicals in biological samples was developed using the MRM-profiling mass spectrometry, which suggested and confirmed the presence of four target compounds among the 87 evaluated in human urine samples, being them metformin, acrylamide, acetaminophen and metoprolol. (AU) | |
| FAPESP's process: | 18/11700-7 - Determination of pharmaceuticals in wastewater |
| Grantee: | César Augusto Marasco Júnior |
| Support Opportunities: | Scholarships in Brazil - Master |