Rayleigh light scattering detection of three α1-adrenoceptor antagonists coupled with high performance liquid chromatograph

• We examine phase polymorphism of [Cd(DMSO)6](BF4)2.
• The crystal structures of Cr 3 and Cr 1 phase are different.
• The fast reorientational motions of the BF4− and CH3 are slowed down below 218 K.

Herein, a Rayleigh light-scattering (RLS) detection method combined with high performance liquid chromatograph (HPLC) without any post-column probe was developed for the separation and determination of three α1-adrenoceptor antagonists. The quantitative analysis is benefiting from RLS signal enhancement upon addition of methanol which induced molecular aggregation to form an hydrophobic interface between aggregates and water that produce a sort of superficial enhanced scattering effect. A good chromatographic separation among the compounds was achieved using a Gemini 5u C18 reversed phase column (250 mm × 4.6 mm; 4 μm) with a mobile phase consisting of methanol and ammonium acetate–formic acid buffer solution (25 mM; pH = 3.0) at the flow rate of 0.7 mL min−1. The RLS signal was monitored at λex = λem = 354 nm. A limit of detection (LOD) of 0.065–0.70 μg L−1 was reached and a linear range was found between peak height and concentration in the range of 0.75–15 μg L−1 for doxazosin mesylate (DOX), 0.075–3.0 μg L−1 for prazosin hydrochloride (PRH), and 0.25–5 μg L−1 for terazosin hydrochloride (TEH), with linear regression coefficients all above 0.999. Recoveries from spiked urine samples were 88.4–99.0% which is within acceptable limits. The proposed method is convenient, reliable and sensitive which has been used successfully in human urine samples.

The α1-adrenoceptor antagonists can interact with methanol, the association particles were formed by hydrophobic interaction, because of adding organic solvent and cause α1-adrenoceptor antagonists molecular get together, form an interface between congeries and water, and then produce a sort of superficial enhanced scattering effect which is advantageous to the enhancement of RRS.Figure optionsDownload as PowerPoint slide