In complex mixture analysis, new approaches and techniques are needed in order to extract the required data from the total ion current chromatogram. Although two-dimensional GC can chromatographically deconvolve complex samples, it can be a relatively expensive and time-consuming process that may not always be the best choice for routine analysis. Retention time locked GC-MS techniques, with dedicated libraries, work well when thesample increases, however, a limit is reached beyond which powerful spectral deconvolution algorithms are needed to extract component spectra from complex spectral background.
In this presentation, interactive mass spectrometry deconvolution software (IST for GC-MS) is used to determine the presence of trace pesticide levels in a complex essential oil. The oil is injected without sample preparation and the chromatography is run under accelerated heating conditions at either 40°C/min or 120°C/min to give total run-times of between 5 min and 10 min. The IFD algorithms, the core technology, extend measurement sensitivity by deconvoluting the spectral fi ngerprint of the target compound from the random nature of instrumental noise. Method detection limits are also improved as the target compound fi ngerprint is separated from the random “sampleto- sample” variation of chemical background and spectral noise. In this way reporting limits approach method detection limits, which increases measurement precision and robustness. The software has unique and powerful interactive software features for QC
validation of target compounds. The simple visual presentation and table format of the scan-to-scan data fi t allows the analyst to judge whether the compound is truly present in the sample.