23 January 2021
By Laura McGregor (Product Marketing Manager, SepSolve Analytical Ltd)
What is untargeted analysis?
Continual advances in sample introduction, chromatographic separation and detection by mass spectrometry means we can now gain greater insight into sample composition than ever before. But we may ask: “What am I going to do with all of this data?”.
With targeted analysis, we focus on detecting a set number of known compounds, so we have prior knowledge of what retention times, spectra or retention indices to use, and can easily prepare processing methods.
With untargeted analysis, we don’t have that luxury. We simply don’t know which compounds are important and need to extract as much information from the data as possible to draw meaningful conclusions.
In recent years, there has been increased demand for untargeted workflows across a diverse range of applications, such as discovery-based analysis for novel biomarkers of disease and the detection of food fraud, where many of the possible adulterants remain unknown.
How can we be sure we aren’t missing something
However, untargeted analysis isn’t straightforward.To get a fingerprint of an entire sample, time-consuming manual data processing is often used to collate a global peak list that represents all samples in the dataset prior to applying chemometrics.
During this step, how can we be sure we haven’t missed an important trace difference, simply by setting an integration threshold too high? Also, how can we prevent retention time drift, which can add errors to an analysis by causing misalignment of the peak tables?
How can chemometrics software help?
With ChromCompare+, the chemometrics platform from SepSolve Analytical, all the raw GC or GC×GC data can be utilised (see workflow below). This automated approach removes the need for laborious pre-processing steps and manual peak table curation, while reducing the risk of missing significant trace differences. Importantly, automated alignment of the chromatograms is included in the workflow to account for retention time drift and improve confidence in the results.
These innovative tools accelerate untargeted workflows, reducing normal processing time from days to minutes, for a wide range of GC and GC×GC applications.
Dr Laura McGregor has a background is in analytical forensic science, and her Ph.D. (at the University of Strathclyde, UK) focused on the chemical fingerprinting of environmental contamination using GC×GC−TOF MS. Following roles in application support and product marketing for Markes International’s TOF MS and software portfolios, she joined SepSolve in October 2017, where she oversees marketing activities across the full product range.