The standard stock solution of praziquantel (100 [micro]g/mL) was used to prepare a set of diluted standard solutions of various concentrations (1-20 [micro]g/mL) prepared by pipetting appropriate volumes (0.1, 0.5, 1, 1.5, 2 mL) of stock solution into 10.0-mL volumetric flasks
and adjusting the volume to the mark with distilled water.
In order to prepare 100 mL of 0.2% w/v positive quality control, 200 mg of caffeine standard was accurately weighed and dissolved in 50 mL distilled water in volumetric flask
and, in the end, the final volume made up to 100 mL with distilled water.
To prepare the energy inhibitor 2,4-dinitrophenol stock solution, 2,4-dinitrophenol was precisely weighed at 0.9225 g, and placed in a 25-mL volumetric flask
. Then, the acetone solution was added to dilute the solution to the required scale, and the solution was shaken well before use.
(6) Cylindrical stainless steel volumetric flasks
were used (100 mm in diameter, 650 mm in height).
Serial dilutions were prepared from the stock solution of hydrocortisone reference standard (1 mg/ml) by pipetting 8.0 ml, 4.0 ml, 2.0 ml, 1.6 ml, 0.8 ml, and 0.4 ml of the stock solution into separate 20 ml volumetric flasks
. The solutions were made up to volume with the diluent and mixed thoroughly.
The mixture was heated at 100 degC for 20 minutes on water bath and after cooling transferred to volumetric flasks
and made the volume up to 10 mL with distilled water.
In 1000 ml volumetric flask
600 ml of Potassium Hydroxide buffer was transferred and then 400 ml Acetonitrile to prepare a mobile phase.
10 ml of the filterate was taken out using a pipette and transferred to a 100ml volumetric flask
. Required volume of working concentration of 50g/ml was obtained by using 0.1N HCl.
110851-200605)-were accurately weighed into a 50 ml volumetric flask
and dissolved in n-hexane at exactly this volume.
Gravimetric addition of the diluent also means the amount of solution prepared is not dictated by the sizes of volumetric flask
that the operator has to hand.