A general method has been elaborated to characterize peak homogeneity. The method uses two detection techniques and ratio formation of two simultaneous signals, arising from the same detector cell section. The feasibility of the method is exemplified by the analysis of partially overlapping codeine-hydrocodone and completely overlapping codeine-oxycodone samples, where peak homogeneity could be characterized by dual CD and UV detection. The S(CD)/S(UV) ratio, and analogous ratios for other, coupled dual detection techniques, are proven to be concentration-independent intensive parameters of the analytes and can be used for identification purposes much more readily than retention times. The observed ratio clearly shows the pure section(s) of the peak. Component composition can also be calculated in the case of heterogeneous peaks, and the ratio shows even the enantiomeric purity/impurity if achiral chromatography is hyphenated with dual (CD and UV) detection.
ASJC Scopus subject areas
- Analytical Chemistry