Design novel optical sensor for determination of bismuth based on immobilization of 4-(4-nitrophenyl)-1-naphthol on a triacetylcellulose membrane

A novel optical sensor has been proposed for sensitive determination of bismuth ion based on immobilization of 4-(4-nitrophenylazo)-1-naphthol on a triacetylcellulose membrane. Chemical binding of bismuth ions in solution with a 4-(4-nitrophenylazo)-1-naphthol immobilized on the triacetylcelluse surface could be monitored spectrophotometrically. The optode shows excellent response over wide concentration range 0.4-3.6 μg mL-1 bismuth with a limit of detection of 0.14 μg mL-1 bismuth. The influence of factors responsible for the improved sensitivity of the sensor were studied and identified. The response time of the optode was 30 sec for a stirrer solution. The influence of potential interfering ions on the determination of 0.4 μg mL-1 bismuth was studied. The proposed optode was applied to the determination of bismuth in pharmaceutical formulation samples.