Chromatographic peak purity

An algorithm for an assesment of chromatographic peak purity was proposed. In this study ethyl 8-methyl-4-oxo-4/7-pyrido[l, 2-u]pyrimidine-3-carboxylate was also used (97MI13). Ethyl 7-methyl-4-oxo-4//-pyrido[l,2-u]pyrimidine-3-carboxylate, among other compounds, was applied to show practical mathematical tools for the creation of several figures of merit of nth order instrumentation, namely selectivity, net analyte signal and sensitivity (96ANC1572). 

G. W. Schieffer, Limitation of assessing high-performance liquid chromatographic peak purity with photodiode array detectors, J. Chromatogr., 379 387 (1985). 

D. Lincoln, A. F. Fell, N. H. Anderson, and D. England, Assessment of chromatographic peak purity of drugs by multivariate analysis of diode-array and mass spectrometric data, J. Pharm. Biomed. Anal., 70 837-844(1992). 

Fig. 3 Investigation of chromatographic peak purity by diode array detection (A) spectra of drug substance and impurity (B) coelution of a mixture containing about 10% impurity (C) coelution of a mixture containing about 0.5% impurity. The spectra were obtained in the peak maximum, at about 5% and 50% of each side of the peak. The normalization was performed with respect to the first spectrum at the peak front (a matchfactor of 1000 means identical spectra) using commercial software.

Fig. 4 Investigation of chromatographic peak purity by means of LC-MS. The top and bottom trace show the UV chromatogram at 240 nm and the extracted ion chromatogram for a mass-to-charge ratio (m/z) 325. Insets A and B display (two of the) mass spectra taken at different retention time ranges of the UV-peak. Optimizing the chromatographic conditions resulted in a separation of the impurity which amounts to 0.5% area at 240 nm (data not shown).

Bryant, D.K. Kingswood, M.D. Belenguer, A. Determination of liquid chromatographic peak purity by electrospray 40. ionization mass spectrometry. J. Chromatogr. A. 1996, 721,... 

Specific detection is an analytical determination based on specific responses related to the chemical characteristics of a molecule excited by a certain type of irradiation. In this detection method, measurement of the molecule of interest may usually be performed without separation from matrix materials or from other ingredients if appropriate instrumental adjustments are made. The need for identification and structure elucidation for newly discovered compounds drives the progress of specific detection techniques with NMR and X-ray diffraction and MS. The UV-diode array detector often aids the recognition of chromatographic peak purity, ensuring complete resolution of a separation procedure. 

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