Colorimetric of aspirin determination

antiplatelet effect by inhibiting the production of thromboxane

Acetyl salicylic acid

determine the amount of aspirin in a commercial aspirin product.

used to determine the purity of the aspirin produced in the Microscale Synthesis of Acetylsalicylic Acid lab.

purposes

principle

Exx NaOH

∆

+

FeCL3

Neutralize Why?

Colored complex (violet)Intensity of color direct relationship

with substance concentration

To prevent form

Fe(OH)3

By what? Conc.HCL

Na acetate

Na salicylate

Part I: making standard

procedure

Weight 0.4 g of acetyl salicylic acid (authentic powder)

and put in 100 ml beaker then Add 20 ml distilled water

then add 10 mL of a 0.5N NaOH then heat it on hot plate until

boiling then add 2 drops Ph.ph togive pink

color then add Conc. HCL to neutrlize

Quantitatively transfer the solution to a 250 mL volumetric

flask, and dilute with distilled water to the mark..

Pipet a 5 mL of standard solution to a 100 mL volumetric flask.

then add 5 ml of FeCL3 solution then complete to market with

distilled water.

Label the flask .

Part II: making sample

put one tablet in 100 ml beaker then add 20 ml distilled water by measure then add 5 ml of 0.5 N NaOH .

Heat it on hot plate until boiling the add 2 drops Ph.Ph. To give pink Color then add Conc. HCL to neutralize it .

Filtrate it onto volumetric flask 250 ml by using fitter paper and

Funnel then complete with distilled water (mix well)

Pipette 5ml of sample solution to 100 ml volumetric flask .

Add 5 ml of 5% FeCL3 solution then complete with distilled water To the market. ( mix well).

Label the flask.

Part III: making blank

Put 5 ml of FeCL3 to 100ml volumetric flask then complete

the volume by distilled water

Measure the absorbance at λ max 510 nm

Standard sample blank

Calculation

for standard

concentration of standard is 8 mg/100 ml (mg%)

ᶜᶬ A 1%

For sample

Calculated Conc. Practical Conc.

= 2 mg /100ml (mg%)

1-beers law.

2-matching point.

% recovery

(95-105)

Practicale calculated

According to the result we can say the tablet accepted or rejected

X100