ISSN: 7027-2221

Keywords : Spectrophotometric determination


Spectrophtometric determination of Resorcinol in aqueous solutions and some Bulk Samples by coupling with Diazotized 4- Methoxy aniline

Zainab Talib Abd Al-Kadum; Kassim Hassan Kadim

karbala journal of pharmaceutical sciences, Volume 6, Issue 10, Pages 0-0

A simple, rapid and sensitive spectrophotometric method for determination of microgram
amounts of Resorcinol in aqueous solution and some bulk samples was described.The method is
based on a diazotization and coupling reaction between resorcinol and diazotized 4-bromo Methoxy
aniline in basic medium to form an intense brown water-soluble dye that is stable, which shows
maximum absorption at 448nm. Beer’s law is obeyed over the concentration range of(0.4-4.4)
μg.ml-1 of resorcinol , with a molar absorptivity of 2.7844×104 l mol-1 cm-1, and Sandell sensitivity
index of 0.0039 μg/cm2 The method does not resort to temperature control or to solvent extraction.
The optimum conditions for all colour development are described and proposed methods were
successfully applied to the determination of resorcinol in aqueous solution and some bulk samples.

Asensitive colorimetric method for the determination of Methyldopa in pharmaceutical preparation via oxidative coupling organic reaction with Thiamine Hydrochloride in the presence of potassium periodate

Muneer . A . A . AL-Da; amy; Rashwan . F. AL-Moswi

karbala journal of pharmaceutical sciences, Volume 4, Issue 6, Pages 69-77

A simple, accurate and sensitive spectrophotometric method for the determination of Methyldopa in pure and pharmaceutical preparations has been developed .The proposed method uses Thiamine Hydrochloride as anew chromogenic reagent . The method is based on the oxidative coupling reaction of Methyldopa with Thiamine Hydrochloride with potassium periodate in neutral media to form orange water soluble dye product , that has a maximum absorption at λmax 480 nm . Linear calibration graph was in the range of (1.00–25.00) µg.ml-1 with molar absorptivity of (0.53 ×104 L.mol-1.cm-1) ,a sandall sensitivity of (4.49 ×10-5 µg.cm-2) , correlation coefficient of (0.9997) , detection limit (0.38 µg.ml-1) and the relative standard deviation of RSD% (0.97) . The method was applied successfully for the determination of Methyldopa in pharmaceutical preparations and the value of recovery % was better than (102%)