Avaliação de métodos de preparo de amostras para posterior determinação de contaminantes inorgânicos em cápsulas de uso farmacêutico

Abstract

In this work, sample preparation methods were proposed, microwave-induced combustion (MIC) and microwave-assisted wet digestion (MAWD), for further Br, Cl, Cr, Cu, I and Mn determination in pharmaceutical capsules. For Cl, Br and I determination, ion chromatography (IC) and inductively coupled plasma mass spectrometry (ICP-MS) were used. The ICP-MS technique was also used for Cr, Cu and Mn determination, as well as graphite furnace atomic absorption spectrometry (GF AAS) and by solid sampling graphite furnace atomic absorption spectrometry (SS GF AAS). For MAWD digestion, it was possible to digest 300 mg samples, whereas in MIC up to 500 mg of sample were used. Also, MIC digestion allowed the digestion using diluted nitric acid for all elements, except for Br and I which require diluted alkaline solution. The carbon content was determined in samples after decomposition in order to evaluate the efficiency of decomposition. Sample decomposition was complete for all sample preparation methods applied, since the carbon content in MAWD solutions was 60 mg L-1 and it was lower than the limit of detection (10 mg L-1) for MIC solutions. Certified reference material of whole milk powder was used to evaluate the accuracy of MIC digestion and the agreement to certified values was between 94 and 102%. In conclusion, the investigated sample preparation methods were suitable to pharmaceutical capsules digestion as well as for the determination techniques. Also, chlorine recovery was possible with diluted acid solutions in MIC digestion.