Determination of Height Equivalent to a Theoretical Plate and Van Deemter Constants for C8 and C18 Columns by using High Performance Liquid Chromatography
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This paper reports C8 and C18 columns efficiency which were determined for separation mixture of Methylparaben (MP), Propylparaben (PP) as solutes test and Uracil (Ura) for measuring the dead time to by applying new chromatographic conditions on two columns. Determination mixture of Methylparaben, Propylparaben and Uracil on two columns was effected by using an isocratic mobile phase of water: acetonitrile 55: 45 (v/v) on a Shim-pack clc-C8 (25 cm × 4.6 mm, 5 μm) and SGE C18 HQ 105 column (25 cm x 4.6 mm, 5 μm) with different flow rates: (0.05, 0.10, 0.15, 0.20, 0.40, 0.60, 0.80, 1.00, 1.20, 1.40, 1.60) mL/min. The detector wavelength was set at 245 nm and sample injection volume 20 μL. Under these conditions efficiency, performance of column, height equivalent to a theoretical plate H, velocity u and Van Deemter curves HETP = f (u) were determined. In addition, a specific, rapid and simple RP-HPLC method has been developed for the simultaneous quantification of Paracetamol (Par), Diclofenac potassium (Dic.p) in standard solutions and tablets. The separation was carried out by using a mobile phase consisting of acetonitrile: phosphoric acid pH=2.43in ratio of 60/40 (v/v). Due to good column efficiency of Shim-pack clc-C8 (25 cm x 4.6 mm i.d., 5 μm), it was used to separate Paracetamol and Diclofenac Potassium, with flow rate of 1.0 ml/min using UV detection at 274 nm. The retention times of Paracetamol and Diclofenac Potassium were found to be 3.03 min and 6.68 min respectively. The analytical method can be successfully adopted for quality control tests for these drugs in tablet dosage forms.
HPLC, Van Deemter, Methylparaben, Propylparaben.