[Construction and characterisation of a selective membrane electrode for the assay of lisinopril]
Mădălina Vieriu1, Nela Bibire, Gladiola Tântaru
1Facultatea de Farmacie, Disciplina de Chimie Analitică, Universitatea de Medicină si Farmacie Gr.T. Popa Iaşi.
Unlabelled:
In order to analyze lisinopril using a selective membrane electrode, the electro-active compound was obtained and included in the selective membrane. The new analysis method was developed and validated.
Material And Method:
The electro-active compound was obtained through the precipitation of lisinopril in acidic media using silicowolframic acid solution. The membrane was obtained by mixing the electro-active compound with polyvinylchloride using tetrahydrofurane as solvent. The solution was evaporated in order to obtain a thick membrane, which was then attached at one end of a polyvinylchloride tube. The internal Ag/AgCl reference electrode was inserted in that tube. The assembly was filled with a lisinopril internal solution. The electrode was characterized by establishing the following characteristics: electrode slope, selectivity, optimal pH range, response time and life-time period. The developed method was validated.
Results:
The method showed a good linearity in the range of 10(-7) and 10(-2)M (the correlation coefficient r = 0.9991). The detection limit (LD) was 8,66 x 10(-8)M and the quantification limit (LQ) was 7,8 x 10(-7)M. There were established the precision (RSD = 1.73%) and the accuracy (mean recovery was 99.92%)
Conclusions:
The experimental results demonstrated a good sensibility.
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