Monitoring of Sulfonamides by a Multicommutation Flow-Analysis Assembly: Use of Quenching Effect on Terbium Luminescence

Abstract

Sulfonamide drugs are an important class of antimicrobial agents employed in both medicine and veterinary practice. Although there have been a variety of proposed analytical methods for their determination, many of them are not suitable for routine quality control, due to time-consuming procedures or expensive instrumentation. In this paper, we propose a simple methodology, based on the direct quenching effect produced by several sulfonamide compounds (sulfasalazine, sulfanilamide, and sulfamethoxazole) on the terbium (III) luminescence. The flow assembly was designed making use of the automatic methodology multicommutation, and the proposed method allowed the determination of up to 50 samples per hour.

Keywords:

• Automation
• Lanthanide luminescence
• Multicommutation
• Quenching
• Sulfonamides

The authors are grateful to the “Consejería de Innovación, Ciencia y Empresa (Junta de Andalucía),” Project P07-FQM-02673, for financial support. L. M. G. also acknowledges a grant from University of Jaén.

Notes

^a Analyte concentration, 12 µg mL⁻¹(n = 10).

^b Stern-Volmer constant.

Composition: ¹Tablets: 500 mg sulfasalazine. ²Powder: 5 g sulfanilamide. ³Eye drops: 6 mg ephedrine hydrochloride; 5 mg sulfanilamide, per 1 mL. ⁴Tablets: 400 mg sulfamethoxazole; 80 mg trimethoprim; 5 mg bromhexine. ⁵Capsules: 400 mg sulfamethoxazole; 80 mg trimethoprim. ⁶Tablets: 400 mg sulfamethoxazole; 80 mg trimethoprim.