title: Comparison of multivariate curve resolution strategies in quantitative LCxLC: Application to the quantification of furanocoumarins in apiaceous vegetables.
abstract: Comprehensive two-dimensional liquid chromatography (LC × LC) has been gaining popularity for the analysis of complex samples in a wide range of fields including metabolomics, environmental analysis, and food analysis. While LC × LC can provide greater chromatographic resolution than one-dimensional LC (1D-LC), overlapping peaks are often still present in separations of complex samples, a problem that can be alleviated by chemometric curve resolution techniques such as multivariate curve resolution-alternating least squares (MCR-ALS). MCR-ALS has also been previously shown to assist in the quantitative analysis of LC x LC data by isolating pure analyte signals from background signals which are often present at higher levels in LC x LC compared to 1D-LC. In this work we present the analysis of a dataset from the LC × LC analyses of parsley, parsnip and celery samples for the presence and concentrations of 14 furanocoumarins. Several MCR-ALS implementations are compared for the analysis of LC × LC data. These implementations include analyzing the LC x LC chromatogram alone, analyzing the one-dimensional chromatogram alone, as well as two hybrid approaches that make use of both the first and second dimension chromatograms. Furthermore, we compared manual integration of resolved chromatograms versus a simple summation approach, using the resolved chromatographic peaks in both cases. It is found that manual integration of the resolved LC × LC chromatograms provides the best quantification as measured by the consistency between replicate injections. If the summation approach is desired for automation, the choice of MCR-ALS implementation has a large effect on the precision of the analysis. Based on these results, the concentrations of the 14 furanocoumarins are determined in the three apiaceous vegetable types by analyzing the LC × LC chromatograms with MCR-ALS and manual integration for peak area determination. The concentrations of the analytes are found to vary greatly between samples, even within a single vegetable type.
authors.affiliation: Department of Chemistry, Virginia Commonwealth University, Richmond, VA 23284, USA.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Cook
authors.affiliation: Department of Chemistry, Gustavus Adolphus College, St. Peter, MN 56082, USA.
authors.forename: Mackenzie L
authors.initials: ML
authors.lastname: Burnham
authors.affiliation: Department of Chemistry, Gustavus Adolphus College, St. Peter, MN 56082, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Harmes
authors.affiliation: Department of Chemistry, Gustavus Adolphus College, St. Peter, MN 56082, USA.
authors.forename: Dwight R
authors.initials: DR
authors.lastname: Stoll
authors.affiliation: Department of Chemistry, Virginia Commonwealth University, Richmond, VA 23284, USA. Electronic address: srutan@vcu.edu.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Rutan
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D011564:Furocoumarins / Q000032:analysis*; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D014675:Vegetables / Q000737:chemistry*
chemical_list: D011564:Furocoumarins
keywords: Chemometrics; Comprehensive two-dimensional liquid chromatography; Diode array detector; Multivariate curve resolution; Quantification