Flow-injection iodimetric determination of captopril in pharmaceutical preparations
A simple, fast and low cost procedure for spectrophotometric determination of captopril in pharmaceutical preparations is described. The procedure is based on a flow-injection system exploiting the on-line formation of the triiodide reagent, which is consumed in the presence of the analyte generating a transient signal. Linear response was observed up to 200 µmol L-1 with a detection limit of 1.0 µmol L-1 (99.7% confidence level). The coefficient of variation (n = 20) and the sampling rate were estimated as 1.2% and 72 determinations per hour, respectively. The main excipients found in pharmaceutical preparations did not affect the captopril determination. The zone sampling approach was exploited to implement on-line dilutions, aiming direct analysis of sample extracts. Results of the analysis of commercial samples agreed with the obtained by the titrimetric reference procedure described in the US-Pharmacopeia at the 95% confidence level. The reagent consumption was estimated as 18 µg of KMnO4 and 10 mg of KI per determination, with a cost of US$ 2.50 per 1000 determinations.
| Main Authors: | , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedade Brasileira de Química
2009
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532009000200007 |
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