ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Sensitive determination of nitrogenous hydrochloride drugs via their reaction with ammonium molybdate

Suling Feng and Limin Guo

College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, 453007, China

E-mail: slfeng@henannu.edu.cn

Received: 3 October 2007  Revised: 14 December 2007  Accepted: 21 December 2007

Abstract: In a hydrochloric acid medium, benzhexol hydrochloride, cyproheptadine hydrochloride, and maprotiline hydrochloride, can react with ammonium molybdate to form ion-association complexes by virtue of electrostatic attraction and hydrophobic interaction which result in a significant enhancement of the resonance light scattering intensity. The maximum scattering wavelengths were found at 364 nm, 364 nm, and 381 nm for benzhexol hydrochloride, cyproheptadine hydrochloride, and maprotiline hydrochloride systems, respectively. Spectral characteristics of the three systems, influencing factors, and optimum conditions were investigated. The reason of resonance light-scattering enhancement and the mechanism of interactions between the drugs and ammonium molybdate were also discussed. Based on the linear relationship between the enhanced intensity of resonance light scattering and the concentration of drugs, a highly sensitive method for the determination of the three drugs was developed, the detection limits being 0.0110 μmol L⁻¹, 0.0038 μmol L⁻¹, and 0.0155 μmol L⁻¹ for benzhexol hydrochloride, cyproheptadine hydrochloride, and maprotiline hydrochloride, respectively. The method was successfully applied to the determination of the investigated drugs in pharmaceutical, serum, and urine samples.

Keywords: resonance light scattering - ammonium molybdate - benzhexol hydrochloride - cyproheptadine hydrochloride - maprotiline hydrochloride - absorption spectra

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-008-0047-6

Chemical Papers 62 (4) 350–357 (2008)