Simultaneous Determination of Atenolol and Amlodipine Using Second Derivative Spectroscopy

The present study describes employing second derivative spectrophotometry for simultaneous determination of atenolol and amlodipine in pure form and in commercial formulations. The method is simple, accurate, precise and economic. Zero crossing point technique was used for analysis of the drugs in the combined formulation. The method was found to be linear in the concentration range 5.0-50.0µg/ml of atenolol at 251nm and 5.0-45.0µg/ml of amlodipine at 264nm. The proposed method was successfully applied to determine atenolol and amlodipine in combined dosage as well as in a separate dosage. The obtained results were in good agreement with standard method.

Environmental Method to Determine Dopamine and Ascorbic Acid Simultaneously via Derivative Spectrophotometry

Many various methods were applied to determine dopamine and ascorbic acid simultaneously using hazardous materials and complex procedures. Derivative absorption spectra can give safely and five sensitive derivative equations that are used for the simultaneous determination of dopamine and ascorbic acid in the UV region, using first and second derivative spectroscopy with high precision at pH value of 9.2. Dopamine and ascorbic acid can be detected in the ranges of 0.375–9.45 mg L−1and 0.352–5.28 mg L−1, respectively. These obtained methods could be used to determine both reagents in real and synthesized samples.

Total porphyrin and coproporphyrin and uroporphyrin fractions in urine measured by second-derivative spectroscopy

A second-derivative scan of an acidified urine sample allows the amplitude of deflection (delta A) and the minimum wavelength of the trough (lambda min) to determine the correct porphyrin concentration and the coproporphyrin:uroporphyrin (copro:uro) ratio, respectively, from a nomogram constructed from calibrator solutions. We measured 24 urine samples for total porphyrin as coproporphyrin equivalents and adjusted the results with factors from the nomogram. The adjusted results (x) (mean +/- SE, 501 +/- 57 nmol/L) compared favorably with the expected results (y) (514 +/- 57). The regression equation and correlation coefficient were: y = 0.993x - 8.9 (r = 0.998, S(y/x) = 16.2). Results of the copro:uro ratio derived by second-derivative spectroscopy and HPLC showed no significant difference (chi 2-test) from samples with various copro:uro ratios. Recovery studies on four urine samples supplemented with known proportions of coproporphyrins and uroporphyrins gave good agreement between the measured and the expected porphyrin ratios. The overall imprecision (CV) of the assay ranged from 3.6% to 6.0% for coproporphyrin and from 3.2% to 9.1% for uroporphyrin.