Cyclic β-(1→3),(1→6) glucans (CBGs) isolated from Bradyrhizobium japonicum bacteria are the periplasmic oligosaccharides having cyclic structures. This paper presents the isolation of CBGs from the bacteria cultured using optimized medium that improved yields to 350-450 mg per gram of cellular dry weight along with analytical interaction with lead(II) ions in the range 33.0-2.0 ppm with CBG as a binding ligand, using constant wavelength synchronous fluorescence spectroscopy. The binding ability of CBGs towards lead(II) is clearly evident from the scanning electron microscopy (SEM) images. The theoretical calculations using HEX 8.0 gave an insight about the interaction between CBG and lead(II) to be in the ratio of 3:1. The method displayed the sensitivity and selectivity towards lead(II) ions up to 2.0 ppm. This observed property of CBGs can potentially hold an application in bioremediation of the soil contaminated with lead.
KEYWORDSThree simple, sensitive and accurate spectrophotometric methods (A, B and C) were developed to determine doxofylline in bulk and in its dosage forms. Method A is based on charge-transfer complex formation of the drug with p-chloranilic acid. Method B involves the formation of colored chloroform extractable ion-pair complex of the drug with bromophenol blue under acidic condition. Method C is based on ternary complex formation of the drug with molybdenum(V) thiocyanate binary complex. The colored products are quantitated spectrophotometrically at 540, 390 and 690 nm by methods A, B and C, respectively. The variables, which affected the reactions were carefully studied and optimized. The linear ranges for the proposed methods were 4-32 μg/mL (method A & B) and 2-16 μg/mL (method C). Analytical performance of the methods was statistically validated. The proposed methods were successfully applied to the analysis of doxofylline in its dosage forms and were found to be comparable with that of reference method.
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