Determination of meloxicam and flufenamic acid using lanthanides sensitized luminescence and sequential injection analysis in the prescence of co-luminescence reagents
Author
Al-Habsi, .Salim Khalfan Saroor
English abstract
Two highly selective and sensitive luminescence methods for the assay of meloxicam (MX) and flufenamic acid (FFA) in biological fluid (Urine) and tap water are described.
The assay of MX is based on the luminescence sensitization of europium (Eu3+) brought about by complex formation with MX. The luminescence signal for Eu3+ - MX is monitored at lem = 624nm and lex = 360nm using time resolved mode. Experimental factors that influence luminescence were systematically optimized in methanol and aqueous media. Under the optimum conditions linear calibration curves between 0-1000 and 0-800 ppb for MX in methanol and in aqueous medium respectively were obtained with a limit of detection (LOD) of 7.0 ppb MX in aqueous medium. The results obtained for the assay of commercial meloxicam formulations (Mobic and Co-Oxicam) when spiked in urine demonstrated good accuracy and precision. The second method, a novel sequential injection analysis (SIA) approach was developed for the assay of FFA in samples of urine and tap water. The method was based on luminescence sensitization of terbium (Tb3+) by complex formation with FFA, The luminescence signal was monitored at lem = 565nm when excited at het = 298nm using time resolved mode. The SIA configuration consisted of a multiposition (8 ports) valve and a syringe pump for aspiration of the reagents (Terbium, Zinc, TOPO, Triton X-100 and FFA). Experimental factors that influenced fluorescence reaction were systematically optimized in aqueous medium using chemometric optimization. Under the optimum conditions linear calibration curves between 0-1200 ppb for FFA in aqueous medium were obtained with a LOD of 80 ppb. When applied to urine and tap water samples the procedures were found to be free from matrix interferences except for Fe 3+ that had significant interference effects. The results obtained for the assay of FFA in urine and tap water samples demonstrated good accuracy and precision.
