Determination of Peak Purity in HPLC by Coupling Coulometric Array Detection and Two-Dimensional Correlation Analysis

Julio Enrique Oney-Montalvo,Ingrid Mayanin Rodríguez-Buenfil,Ksenia Morozova,Matteo Scampicchio,Manuel Octavio Ramírez-Sucre

doi:10.3390/s22051794

Abstract

This work aims to evaluate the purity of chromatographic peaks by a two-dimensional correlation (2D-corr) analysis. Such an analysis leads to two contour plots: synchronous and asynchronous. The synchronous contour plot provides information on the number of peaks present in the chromatogram. The asynchronous contour plot reveals the presence of overlapping species on each peak. The utility of 2D-corr analysis was demonstrated by the chromatographic analysis of Capsicum chili extracts obtained by HPLC coupled with a coulometric array of sixteen detectors. Thanks to 16 electrochemical sensors, each poised at increasing potentials, the resulting 2D-corr analysis revealed the presence of at least three species on the peak located at a retention time of 0.93 min. Mass spectrometry (MS) analysis was used to analyze the coeluting species, which were identified as: quinic acid (3.593 min), ascorbic acid (3.943 min), and phenylalanine (4.229 min). Overall, this work supports the use of 2D-corr analysis to reveal the presence of overlapping compounds and, thus, verify the signal purity of chromatographic peaks.

Highlights

Analytical interferences occur in chromatography when the signal of a substance is coeluting with the signal of the analyte of interest
Two-dimensional correlation analysis using synchronous and asynchronous plots was applied to determine the peak purity in the analyzed chili extract by HPLC coupled with a coulometric array detector
The synchronous plot provided information on the number of complex peaks present in the chromatogram, while the asynchronous plot was useful to assess the purity of peaks

Summary

Introduction

Analytical interferences occur in chromatography when the signal of a substance is coeluting with the signal of the analyte of interest. One clear example is the contamination of Habanero peppers by mycotoxins, pesticides, or heavy metals, as well as their adulteration with dyes and foreign matter [3] In such cases, the effect of concomitant species in the analytical signal causes a systematic error on the analytical result, i.e., compromising the accuracy of the final outcome. The PCA analysis requires qualified personnel with chemometric knowledge to verify the presence of interferences [6,7]. This has led to the search for alternatives, such as 2D-corr analysis

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