Avaliaçao da estabilidade do ph de soluções tampão

Abstract

In chemical and biological analysis laboratories, buffered solutions are routinely used for analytical tests, however there are few studies that address the durability and stability of these solutions. According to the Brazilian Pharmacopoeia 6thEd. (2019) when preparing a buffer solution, one should consider the stability in the preparation of quantities for consumption, the stability in storage condition being unknown. This work evaluated the stability of the pH/aspect of buffer solutions pH phosphate (2.2 / 6.0), acetate pH (3.0 / 7.0) and citrate-phosphate pH 5.0 prepared as described in the pharmacopoeia, by a period of 29 days stored both at room temperature and also refrigerated both with exposure to light and under conditions of use. The solutions stored under refrigeration (2°C to 8°C) remained stable within the evaluation criteria, which was a variation of 2% from the initial pH obtained, during the period tested. For the solutions stored at room temperature, the pH 5.0 citratephosphate buffer solution did not remain stable after 15 days, the other solutions remained within the specified range. All evaluated solutions did not observe visual changes in their appearance during the tested period.