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Journal of Automated Methods and Management in Chemistry
Volume 2007, Article ID 32470, 7 pages
Research Article

Experimental Design Optimization of a Sequential Injection Method for Promazine Assay in Bulk and Pharmaceutical Formulations

1Department of Chemistry, King Faisal University, P.O. Box 400, Hofuf 31982, Saudi Arabia
2Department of Chemistry, King Fahd University for Petroleum and Minerals, P.O. Box 2026, Dhahran 31261, Saudi Arabia

Received 8 May 2007; Accepted 7 June 2007

Copyright © 2007 Abubakr M. Idris et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Experimental design optimization approach was utilized to develop a sequential injection analysis (SIA) method for promazine assay in bulk and pharmaceutical formulations. The method was based on the oxidation of promazine by Ce(IV) in sulfuric acidic media resulting in a spectrophotometrically detectable species at 512 nm. A 33 full factorial design and response surface methods were applied to optimize experimental conditions potentially controlling the analysis. The optimum conditions obtained were 1.0×104 M sulphuric acid, 0.01 M Ce(IV), and 10 μL/s flow rate. Good analytical parameters were obtained including range of linearity 1–150 μg/mL, linearity with correlation coefficient 0.9997, accuracy with mean recovery 98.2%, repeatability with RSD 1.4% (n=7 consequent injections), intermediate precision with RSD 2.1% (n=5 runs over a week), limits of detection 0.34 μg/mL, limits of quantification 0.93 μg/mL, and sampling frequency 23 samples/h. The obtained results were realized by the British Pharmacopoeia method and comparable results were obtained. The provided SIA method enjoys the advantages of the technique with respect to rapidity, reagent/sample saving, and safety in solution handling and to the environment.