2.4. Procedure for unknown aqueous samples and
pharmaceutical samples
Aqueous samples were prepared by conveniently
diluting different amounts of the stock
solution with HCl 0.01 N. For commercial
tablets, an amount of triturated capsules containing
20 mg of diclofenac was weighed and placed
into a 50.00 ml volumetric flask, dissolved with
distilled water, sonicated for 20 min and filtered.
Then 5.00 ml of the filtrate were placed into
another 50.00 ml volumetric flask and diluted
with distilled water. A final dilution with HCl 0.01
N was performed in order to obtain concentrations
within the linear calibration range. Only in
one case (Voltaren D), the triturated capsule was