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Dushyant Patel Extractive Spectrophotometric Method

S.K.P.C.P.E.R., Kherva 73 M .Pharm. Thesis

Method II (BTB Method)

¾ From the working standard solution, 2.0, 2.5, 3.0, 3.5, 4.0 and 4.5 ml were transferred to

a series of separating funnels and buffer solution (2.5 ml) was added to each separating

funnels, then BTB solution was added in excess and shaken well, and then 10 ml of

chloroform was added to each and shaken well and kept for few minutes. Later the

extracts were taken into 10 ml volumetric flasks, treated with anhydrous sodium sulphate

and made up the volume with chloroform, and then absorbance of the solution was

measured at 421 nm (Figure 5.4) against reagent blank. Final concentrations of analyzed

solutions were 40 µg/ml to 90 µg/ml. The standard calibration plot was prepared to

calculate the amount of the analyte drug in unknown samples.

Figure 5.4 Representative absorption spectra of GBP-BTB showing λmax at 421 nm

b) Accuracy (% Recovery):

¾ The accuracy of the proposed methods was performed by calculating recovery of GBP

by the standard addition method. Known amounts of standard solutions of GBP were

added at 50, 75 and 100% levels to prequantified sample solutions of 40 µg/ml

GBP for

BCG and BTB both. At each level of the amount 3 determinations were performed. The

amount of GBP was estimated by applying obtained values to regression equation.

c) Method precision (Repeatability):

¾ The precision of the instrument was checked by repeated scanning and measurement of

the absorbance of solutions of 50 µg/ml

GBP (n = 6) and 70 µg/ml GBP (n = 6) for BCG

and BTB, respectively without changing the parameters for the method. The repeatability

was expressed in terms of % relative standard deviation (%RSD).

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