Otimização de metodologia alternativa para determinação de ácidos graxos livres, em óleos vegetais, por eletroforese capilar

Abstract

Fats represent, approximately, 33 % of total energy resources consumed by the world population, on average, daily. In the present study, the vegetable oils free acidity values were determined by the technique of capillary zone electrophoresis , with a capillary externally coated with fluoro - polymer ( TSH ), indirect UV detection at 224 nm and temperature controlled within the cartridge at 25 ° C. Samples were injected hydrodynamically ( 12.0 mbar for 4 s ) and the electrophoretic system was operated at normal polarity under constant voltage of + 19 kV . The electrolyte used was 15 mmol L -1 of buffer NaH2PO4 / Na2HPO4 (pH ~ 6.86 ); 4.0 mmol L- 1 SDBS ; 8.3 mmol L-1 Brij 35 ® , 45% v / v ACN and 2.1 % 1- octanol . The results showed that capillary zone electrophoresis can be used as an alternative method in the analysis of free acidity vegetable oils, since there were no significant differences in a range of 95 % confidence , when compared with the official method by alkali titration volume . The advantages of the alternative methodology proposed in this work is the identification of individual present free fatty acids, the lowest volume of solvents and samples, and the lowest human intervention .