Comparison of Pre-Processing and Variable Selection Strategies in Group-Based GC×GC-TOFMS Analysis

Paulina Piotrowski,Benjamin Place

doi:10.3390/separations6030041

Paulina Piotrowski, Benjamin Place

Open Access

https://doi.org/10.3390/separations6030041

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Journal: Separations	Publication Date: Aug 21, 2019
Citations: 1	License type: CC BY 4.0

Affiliation: National Institute of Standards and Technology

Abstract

Chemometric analysis of comprehensive two-dimensional chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS) data has been reported with various workflows, yet little effort has been devoted to evaluating the impacts of workflow variation on study conclusions. The report presented herein aims to investigate the effects of different pre-processing and variable selection strategies on the scores’ plot outputs from GC×GC-TOFMS data acquired from lavender and tea tree essential oils. Our results suggest that pre-processing, such as applying log transformation to the data set, can result in significant differentiation of sample clustering when compared to only mean centering. Additionally, exploring differences between analysis of variance, Fisher-ratio, and partial least squares-discriminant analysis feature selection resulted in little variation in scores plots. This work highlights the effects different chemometric workflows can have on results to help facilitate harmonization efforts.

Highlights

Comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (TOFMS) has become an established technique for the analysis of complex samples [1,2,3].The increased peak capacity and sensitivity obtained through non-targeted GC×GC-TOFMS analysis result in complex data sets, which are time-consuming to analyze [4,5]
The field of GC×GC-TOFMS has embraced the non-targeted analysis of sample groups, where differences between sets of sample groups are of interest
Obtained samples of lavender (L) and tea tree (TT) oils were diluted 1:100 in methanol and analyzed in triplicate by comprehensive two-dimensional gas chromatography coupled to a time of flight mass spectrometer

Summary

Introduction

Comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (TOFMS) has become an established technique for the analysis of complex samples [1,2,3].The increased peak capacity and sensitivity obtained through non-targeted GC×GC-TOFMS analysis result in complex data sets, which are time-consuming to analyze [4,5]. Comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (TOFMS) has become an established technique for the analysis of complex samples [1,2,3]. The increased peak capacity and sensitivity obtained through non-targeted GC×GC-TOFMS analysis result in complex data sets, which are time-consuming to analyze [4,5].

Results

Conclusion