Deconvolution of partially overlapping tailing peaks in diode array high performance liquid chromatography using purity ratios

Abstract

A new approach to deconvolution of diode array HPLC data is described. It is illustrated by the chromatograms of 2-and 3-hydroxypyridine undertaken at pH 4.8, 5.1 and 5.2 representing three different qualities of resolution from almost totally overlapping to well resolved. In all cases peaks are tailing, typical of many real situations. The first step is to select wavelengths using the normalised spectra at each point in time. Next a purity curve is obtained from these wavelengths, which is related to a real purity curve used for deconvolution. It is shown that the method is robust over the full resolvability range.

Quantitative resolution of overlapping tailing peaks obtained by diode-array detector high performance liquid chromatography in the absence of pure standards using simple chemical knowledge

“…14,17 It has been shown that this condition together with other knowledge and constraints on the system is sufficient to provide good deconvolution. 18 This is compatible with theoretical predictions by Manne in 1995. 19 An analyst often has considerable knowledge of a system.…”

“…Purity curve calculations have been described in greater detail previously; 18 however, the implementation used in this paper involves additional steps for wavelength selection and a final overall scaling.…”

“…For example, the relative proportions of two compounds might be known: this has been exploited recently. 18 In the absence of this knowledge, it is still possible to deconvolute peaks, using basic information such as the positivity of the spectra and the unimodality of the chromatographic peaks. Previously, the concept of purity curves has been proposed that relates to the relative proportion of components over a cluster of closely eluting chromatographic peaks.…”

“…Previously, the concept of purity curves has been proposed that relates to the relative proportion of components over a cluster of closely eluting chromatographic peaks. 18 The concept of a purity curve is intuitively obvious to a chromatographer, there being a number of simple, univariate measures (such as absorbance ratios) that are commonly employed in modern chromatographic software. The method in this paper is a sophistication of this concept.…”

Non-parametric linear regression of discrete Fourier transform convoluted densitometric peak responses

“…Analysis of enantiomers giving partially overlapping peaks was also made possible by using different chemometric treatments of chromatographic ultraviolet signals, e.g., quantification of pseudoephedrine enantiomers [4]. Deconvolution of partially overlapping tailing peaks in photodiode array HPLC using purity ratios has also been applied [5]. Semi-automatic deconvolution of chromatographic data to give pure spectral and chromatographic profiles has been found beneficial in the quantitative determination of some pharmaceutical mixtures [6].…”