February 25, 2017

BARCHAN: Blob Alignment for Robust CHromatographic ANalysis (GCxGC)

In 1987, G. P. Barchan et al.  wrote a paper called: Gas chromatographic method of determining carbon monoxide and dioxideBut barkhan, or barchan, means more outside gas chromatography. It refers to sand dunes, with crescent shapes, modeled by the wind.

BARCHAN: crescent-shaped sand dunes

They inspired our image registration tool for comprehensive 2D chromatography peak alignment (GCxGC or GC2D). It was just published as BARCHAN: Blob Alignment for Robust CHromatographic ANalysis (GCxGC), Journal of Chromatography A, February 2017. For given 2D chromatogram areas of interest, a baseline removal (BEADS) is applied, a peak detection is performed, blobs are detected and registered with a mixed rigid/non-rigid transformation based on the Coherent Point Drift technique.

A pair of GCxGC chromatogram areas of interest.
BARCHAN registration, example.

The preprint is here. The HAL and the arxiv version. The abstract is next:

Abstract: (Comprehensive) Two dimensional gas chromatography (GCxGC) plays a central role into the elucidation of complex samples. The automation of the identification of peak areas is of prime interest to obtain a fast and repeatable analysis of chromatograms. To determine the concentration of compounds or pseudo-compounds, templates of blobs are defined and superimposed on a reference chromatogram. The templates then need to be modified when different chromatograms are recorded. In this study, we present a chromatogram and template alignment method based on peak registration called BARCHAN. Peaks are identified using a robust mathematical morphology tool. The alignment is performed by a probabilistic estimation of a rigid transformation along the first dimension, and a non-rigid transformation in the second dimension, taking into account noise, outliers and missing peaks in a fully automated way. Resulting aligned chromatograms and masks are presented on two datasets. The proposed algorithm proves to be fast and reliable. It significantly reduces the time to results for GCxGC analysis.

Highlights

• BARCHAN: 2D chromatogram and template alignment based on peak registration.
• The alignment is performed by probabilistic estimation with a Gaussian Mixture Model.
• It combines a rigid and a non-rigid transformation for complex samples analysis.
• The method accounts for noise, outliers and missing peaks in an automated way.
• BARCHAN significantly reduces the time to results for GC×GC analysis.

This work is a follow-up of preceding chromatography papers:
  1. Chromatogram baseline estimation and denoising using sparsity (BEADS)
  2. Comprehensive Two-Dimensional Gas Chromatography for Detailed Characterisation of Petroleum Products
  3. Characterization of middle-distillates by comprehensive two-dimensional gas chromatography (GCxGC): a powerful alternative for performing various standard analysis of middle distillates
  4. Comparison of conventional gas chromatography and comprehensive two-dimensional gas chromatography for the detailed analysis of petrochemical samples