Sensitive Spectrophotometric Determination of Iron(II) with 2-(5-Bromo-2-pyridylazo)- 5-diethylaminophenol

909-91

Extractional - Spectrophotometric Determination of Fenbendazole and Ornidazole in Pharmaceutical Formulations

Methods for spectrophotometric determination of fenbendazole and ornidazde are described. The methods are based on the formation and extraction of the ion-pair complex formed between bromothymol blue and either fenbendazole (FBZ) or ornidazole (ORN). The extracted coloured complexes absorb at 416 and 446 nm, respectively. The effect of different factors, e.g. pH, organic solvent, reagent concentration, extraction time, shaking time and common interfering species have been investigated. Fenbendazole and ornidazole can be determined over the range 1.2 to 24.0 ppm and 5.5 to 77.0 ppm, respectively. The precision of the methods was tested for the determination of pure samples of FBZ and ORN and the mean RSD was found to be 3.0 and 2.3% for FBZ and ORN, respectively.The proposed methods were successfully applied for the determination of FBZ and ORN in commercially dosage fornis. A comparison between the suggested methods and the other reported methods was also studied

Spectrophotometric determination of enzymatically generated hydrogen peroxide using Sol-Gel immobilized horseradish peroxidase

Peroxidase entrapment in different Sol-Gel matrices was successful. The enzyme did not show a decrease in activity for at least 2 months as well as storage at room temperature and dry condition for periods exceeding 3 weeks. It was evident that the enzymatic activity was a function in the type of the alkoxysilane precursor. In addition, the optimum temperature which resulted in maximum enzymatic activity was also dependent on the type of Sol-Gel matrix. Excellent results were obtained for the determination of glucose in serum samples using soluble glucose oxidase in conjunction with the Sol-Gel entrapped peroxidase. The enzymatically produced hydrogen peroxide is oxidized by the entrapped peroxidase yielding oxygen which oxidizes the faint blue variamine blue into the intensely violet colored species (the molar absorptivity is about 1.8 × 104 1 mol−1 cm−1). The characteristics of this chromogenic system as