Summary
This Application Note shows that BenchTOF time-of-flight mass spectrometers, coupled with GC, can provide a high-performance solution for the detection and quantitation of aroma compounds in wine extracts. In particular, we show how the ChromCompare data-mining module of BenchTOF software allows rapid identification of minor differences between samples. Results also demonstrate how the Select-eV variable-energy ionisation capability of the flagship BenchTOF-Select enhances both the sensitivity and selectivity of analyses.
Introduction
Aroma profiles, such as those for wine, contain a wide variety of components at a range of concentrations. Detection and identification of key compounds with low odour thresholds and compounds responsible for off-odours is a challenging prospect. Gas chromatography coupled with time-of-flight mass spectrometry (GC–TOF MS) is an ideal choice for such analyses. BenchTOF time-of-flight mass spectrometers offer low detection limits, sub-amu selectivity, full-range (referencequality) spectra and fast acquisition speeds, which allow trace components, including adulterants, to be identified even within the most challenging of matrices. This Application Note describes how these benefits are complemented by two unique technologies: ChromCompare data-mining software for the pairwise comparison of complex chromatograms; and Select-eV variable-energy ionisation technology. Select-eV enhances compound identification by generating repeatable, low-energy mass spectra containing structurally-significant fragment ions and an improved molecular ion signal.
Background to BenchTOF instruments
ALMSCO BenchTOF™ time-of-flight mass spectrometers are designed specifically for gas chromatography. They are particularly appropriate for the analysis of aroma profiles, because they offer exceptional sensitivity, spectral quality and speed:
- Sensitivity: Highly efficient direct-extraction technology allows BenchTOF to acquire full-range spectra at sensitivity levels that are similar to or better than SIM detection limits on quadrupole instruments. This allows it to reliably detect and identify trace-level target analytes and unknowns in a single run.
- Spectral quality: The ‘reference-quality’ spectra produced by BenchTOF are a close match for those in commercial libraries such as NIST or Wiley. This enables quick and confident matching of both targets and unknowns.
- Speed: The acquisition rate of 10,000 full-range spectra per second enhances the performance of the latest automated spectral deconvolution and ‘data-mining’ algorithms.
As well as featuring full system control and a comprehensive data-analysis package, the TOF-DS™ software for BenchTOF also features ChromCompare® – an innovative module that saves time and effort when comparing chromatographic profiles. ChromCompare distils the information-rich chromatographic data sets generated by BenchTOF into ‘H-Plots’ or line chromatograms that are understandable at a glance. Each line in the H-Plot represents an identified component, and its height is proportional to the peak area. Libraries of H-Plots can be created to characterise future unknown samples. ChromCompare improves productivity and data confidence, both when comparing GC–MS profiles and when screening large numbers of chromatograms for target compounds.
>> Download the full Application Note as PDF
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