Development and application of microextraction sample preparation techniques to determine pharmaceutical drugs in the environment

Author(s)

Paulo Clairmont Feitosa de Lima Gomes

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT)
• Defense date: 2012-08-10

Examining board members

Fernando Mauro Lanças; Christian Fernandes; Marcos Roberto de Vasconcelos Lanza; Anil Kumar Singh; Marcelo Zaiat

• Advisor: Fernando Mauro Lanças

Abstract

The occurrence of pharmaceutical drugs in the environment is a worldwide problem caused by the genotoxicity and ecotoxicity activities of those compounds. Water is one of most used natural resource in human activities which explain the presence of emerging contaminants. Those compounds affect not only humans but also aquatic animals that spend the whole life cycle in this environment. In order to monitor drugs in the environment, it is essential the development of analytical methods to analyze pharmaceutical drugs in environmental matrices. Moreover, those methods developed are useful for the development of new water treatment techniques, and analysis of drug metabolites formed during the water treatment process. To accomplish all these purposes, chromatographic methods of analysis coupled to mass spectrometry detection are essential to separate the analytes, and further to identify and quantify them unequivocally. Before the analysis, the sample preparation step is fundamental to concentrate the analytes, eliminate and clean-up all the matrices interferents. Thus, in this thesis is described the development of 2 methods, one using conventional gas chromatography coupled to mass spectrometry (GC-MS), the latter one using comprehensive two dimensional gas chromatography coupled to time of flight mass spectrometry (GCxGC-ToF/MS) to analyze pharmaceutical drugs in water matrices. In both methods, solid phase microextraction (SPME) was used in the sample preparation procedure. In the SPME-GC-MS method in situ derivatization was applied to improve the chromatographic separation, providing neat and sharp peaks. This method were applied to analyze river, sewage and wastewater samples. In all samples were detected the presence of pharmaceutical drugs. However, one wastewater sample from the entrance of wastewater treatment plants (WWTP) presented ketoprofen in the concentration level of 1050 ng L-1. GCxGC-ToF/MS method it was possible to accomplish a complete separation of 13 analytes absent of peak tailing, co-elution and degradation without a derivatization reaction. River water samples were analyzed using this method, although, in none of the compounds were present in the samples. In both methods, an experimental design was used to optimize the SPME extraction and derivatization reaction. A second phase in this study explored the development of new polymeric phases for stir bar sorptive extraction (SBSE). About 7 new phases were developed, all phases were mixed of polidimethylsiloxane (PDMS) with other polymeric phases or with adsorptive material. All these new phases were tested and compared against the comercial version in the extraction of 9 pharmaceuticals compounds in water. The mixed polymeric phase of PDMS and OV-17-vinyl demonstrated a suitable selectivity to extract all pharmaceutical drugs in water. Also, a SBSE bar containing activated carbon 5% was applied in the analysis of phenol in urine. Also, it was studied the development of new polymeric phases applied for the vial wall sorptive extraction (VWSE) used in the analysis of drugs in water. These new phases were based on a mixture of PDMS with activated carbon, and PDMS combined with divinylbenzene (PDMS/DVB) in different amounts of each compound. At least, a new configuration in the VWSE was purposed. This new configuration was tested for the extraction of non-polar (progesterone) and polar (caffeine) compounds in water, and presented adequate response for both compounds. (AU)

• FAPESP's process: 07/03844-4 - Simultaneous analysis of multi-residue antibiotics in water and sediments by headspace bar sorptive extraction with in situ derivatization coupled to GC / MS
• Grantee: Paulo Clairmont Feitosa de Lima Gomes
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)