Levo dopa content

Method for the estimation of Levo dopa content

Reagent  Required:

Anhydrous  formic acid, Anhydrous glacial acetic acid , Dioxan , 0.1M Perchloric acid,

Crystal violet indicator (0.5% w/v solution in Anhydrous glacial acetic acid)

Glass wares and Apparatus Required:

250mL conical flask, Burette

Procedure:

Weigh accurately about 0.3gm of sample dissolve, heating if necessary, in 5 ml of Anhydrous formic acid and add 25 ml of anhydrous glacial acetic acid and 25 ml  of dioxin. Titrate with 0.1M Perchloric acid,

 Using 0.1 ml of crystal violet indicator and titrating to a green end-point. Carry out a blank titration.

1 ml of 0.1M Perchloric acid is equivalent to 0.01972 g of C₉H₁₁NO₄.

Calculation:

Percentage of Levo dopa is calculated as:

                           Titre X 0.01972 x Normality x 100

           =      -----------------------------------------------------

                             Weight of sample X 0.1

Method for preparation of 0.1M Perchloric acid:

Mix 8.5 ml of Perchloric acid with 500 ml of anhydrous glacial acetic acid and 25 ml of acetic anhydride, cool and add anhydrous glacial acetic acid to produce 1000 ml.

Standardization:

Weigh accurately about 0.35 gm of potassium hydrogen phthalate, previously powdered lightly and dried at 120⁰ C for 2 hours and dissolve it in 50 ml of anhydrous glacial acetic acid. Add 0.1 ml of crystal violet solution and titrate with the Perchloric acid solution until the violet colour change to emerald-green. Perform a blank determination and make any necessary correction.

(1 ml of 0.1M Perchloric acid is equivalent to 0.02042 gm of C₈H₅KO₄.)