Flow injection manifold for the direct spectrophotometric determination of bismuth in pharmaceutical products using Methylthymol Blue as a chromogenic reagent.
A new simple and rapid flow injection method is reported for the direct determination of bismuth in pharmaceutical products. Methylthymol Blue (MTB) was used as a chromogenic reagent and the absorbance of the colored Bi(III)-MTB complex produced was monitored at 548 nm. The various chemical and physical variables were optimized and a study of interfering ions was also carried out. Linear calibration graphs were obtained from 0 to 100 mg l-1 Bi(m) (120 injections per hour). The precision was very good (sr = 1.3%) and the limit of detection was cL = 0.150 mg l-1. The average accuracy was also very good (er = 0.75%) and was evaluated by comparison of the results obtained with those claimed by the manufacturers. The method was found to be adequately selective, considering the ions that the samples contain.
Department of Chemistry, Laboratory of Analytical Chemistry, Aristotle University of Thessaloniki, 54006 Thessaloniki, Greece. themelis@chem.auth.gr
D G
DG
Themelis
P D
PD
Tzanavaras
J K
JK
Papadimitriou
D001729:Bismuth / Q000032:analysis*; D001979:Bromthymol Blue / Q000031:analogs & derivatives; D017022:Flow Injection Analysis / Q000379:methods; D007202:Indicators and Reagents; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods
D007202:Indicators and Reagents; D004364:Pharmaceutical Preparations; C002074:methylthymol blue; D001729:Bismuth; D001979:Bromthymol Blue