title: Continuous wavelet transformation applied to the simultaneous quantitative analysis of two-component mixtures.
abstract: In this paper we developed a graphical method based on Haar (HA) and Mexican (MEX) one-dimensional continuous wavelet transforms and we applied it to a mixture of hydrochlorothiazide (HCT) and spironolactone (SP) in the presence of strongly overlapping signals. Keeping in mind to obtain an appropriately transformed spectrum, we tested several values of the scaling parameter a and the point number of the analysed spectrum in the concentration range of 2-22 microg/ml for both active compounds. The optimal values of the scale parameters and the corresponding frequencies were found to be a = 32 and 0.031 for HA and a = 30 and 0.008 for MEX corresponding to 400 points. HA and MEX methods based on a zero crossing technique were applied to the analysed signal and their regression lines at the selected points were obtained. The validation of the above methods was carried out by analysing different synthetic mixtures containing HCT and SP. MATLAB 6.5 software was used for one-dimensional wavelet analysis and the basic concepts about wavelet method were briefly explained. The method developed in this paper is rapid, easy to apply, inexpensive and is suitable for analysing the overlapping signals of compounds in their mixtures without any chemical pre-treatment.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, University of Ankara, Tandoğan ,Turkey. dinc@pharmacy.ankara.edu.tr
authors.forename: E
authors.initials: E
authors.lastname: Dinç
authors.forename: D
authors.initials: D
authors.lastname: Baleanu
authors.forename: O
authors.initials: O
authors.lastname: Ustündağ
authors.forename: H Y
authors.initials: HY
authors.lastname: Aboul-Enein
mesh_terms: D000465:Algorithms; D002138:Calibration; D002626:Chemistry, Pharmaceutical; D003627:Data Interpretation, Statistical; D004232:Diuretics / Q000032:analysis; D004338:Drug Combinations; D006852:Hydrochlorothiazide / Q000032:analysis; D004364:Pharmaceutical Preparations / Q000032:analysis*; D012015:Reference Standards; D012044:Regression Analysis; D015203:Reproducibility of Results; D012996:Solutions; D013148:Spironolactone / Q000032:analysis; D013607:Tablets
chemical_list: D004232:Diuretics; D004338:Drug Combinations; D004364:Pharmaceutical Preparations; D012996:Solutions; D013607:Tablets; D006852:Hydrochlorothiazide; D013148:Spironolactone