Toward automated peak resolution in complete GC x GC-TOFMS chromatograms by PARAFAC

We have previously developed automated PARAFAC methods for resolving peaks from small subsections of data obtained using comprehensive multidimensional gas chromatography with mass spectral detection (GC x GC-TOFMS). Herein, we build upon those previous methods and present a new method for resolving peaks across much larger sections or even entire GC x GC-TOFMS chromatograms using PARAFAC in an automated fashion. In addition, the method presented is demonstrated on three GC x GC-TOFMS data sets: (1) a complete chromatogram of a test mixture of 32 compounds, (2) several compounds spiked into a diesel sample at two known concentrations and (3) a large section of the chromatogram of the headspace of a urine sample collected by solid phase microextraction (SPME), i.e. containing volatile metabolites. The results of these analyses show that the presented method resolves peaks (including overlapping peaks) and provides useful quantitative and identification information as long as some care is taken in the selection of parameters (such as the size of subsections to be analyzed individually by PARAFAC). Analysis time using PARAFAC remains a challenge, but a technique for reducing the amount of time is demonstrated and future possibilities for greatly reducing the analysis time are discussed. Copyright (C) 2009 John Wiley & Sons, Ltd.