Determinação Potenciométrica e Condutimétrica de Carbonato de Lítio em Comprimido Antidepressivo: Uma Sugestão de Prática Para o Ensino de Química Analítica Instrumental

Resumo

Lithium carbonate (Li2CO3) makes up antidepressant pills used in the treatment of bipolar disorder.
Potentiometric and conductimetric acid-base titrations were used to determine the Li2CO3 content in tablet
and in pure Li2CO, named as chemical reference substance (SQR). Potentiometric and conductimetric
titration curves were constructed and processed using the CurTiPot-Cond program. The results obtained
were compared with those obtained by the official method described in the Brazilian Pharmacopoeia
(FB), the acid-base return titration. The results obtained by the acid-base return titration showed that the
amounts of Li2CO3 in the analyzed drug are in accordance with those described in the drug inserts, and
presented precision and accuracy. The F Test and Student’s t Test demonstrated that the results obtained
by potentiometric and conductimetric titrations were consistent with those obtained by the official method.
The feasibility of measuring Li2CO3 in antidepressant pills was demonstrated using the two instrumental
analytical techniques. By using a contextualized approach in the teaching and learning process, showing
that Analytical Chemistry plays an essential role in the quality control of medicines, it is believed that
classes can become more attractive and relevant for students, enhancing this process.