Padronização e validação analítica dos métodos DPX-RAM/LC-MS e MIP-PSI-MS para análise de cocaína em fluido oral
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2017-04-24
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Universidade Federal de Goiás
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The analysis of drugs of abuse in non-conventional biological fluids is attracting a
lot of interest due to recent legislation changes in Brazil and a greater police
surveillance. However, complex matrix samples have a large amount of
endogenous, exogenous and other interfering compounds that make direct
analysis impossible in analytical systems. In this way, sample preparation has
been presented as an important tool for rapid and sensitive analytical methods.
The miniaturized sample preparation technique called disposable pipette
extraction (DPX) has shown to be promising once it integrates the clean-up and
pre-concentration of samples. Restricted access materials (RAM) are a class of
materials that allow the exclusion of endogenous compounds and the extraction
of analytes in a single step. In this manner, in this work a RAM extraction phase
has been developed for DPX applied to the analysis of cocaine in oral fluid via
liquid chromatography coupled with mass spectrometry (DPX-RAM/LC-MS). The
proposed method was optimized using a 24
factorial design. According to the
results obtained, the better efficiency of extraction was obtained in the following
conditions: pH 9, 10 extractions cycles (draw/eject), 3 desorption cycles
(draw/eject) and acetonitrile as desorption solvent. The DPX-RAM/LC-MS method
showed to be linear from 10 to 100 ng.mL-1 and have R2 = 0,999. As an alternative
to sample preparation and a previous separation step, it was also evaluated in this
work, a direct injection system for the mass spectrometer (MS) employing an
ambient ionization source called Paper Spray Ionization (PSI). For this purpose,
molecularly imprinted polymers (MIP) for the analysis of cocaine were synthetized
directly on the surface of a cellulose membrane and employed as paper in a PSI
system. The membrane containing MIP showed to be more selective and had a
greater intensity of signal when compared to the chromatographic paper normally
used for PSI. MIP-PSI method showed to be linear from 1 to 100 ng.mL-1 and have
R2 = 0,998.The methods proposed are precise and accurate with obtained values
bellow 15%, recovery above 80% and the limits of detection and quantification are
lower than the ones found in the literature. Both techniques were standardized
and validated according to ANVISA’s normative.
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TAVARES, L. S. Padronização e validação analítica dos métodos DPX-RAM/LC-MS e MIP-PSI-MS para análise de cocaína em fluido oral. 2017. 88 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Goiânia, 2017.