Electronic nose (HERACLES)

Microwave sample treatment

What is it?:

Heracles is a highly sensitive gas chromatograph which can collect and analyse and identify components, and make a statistical report whether they fit a previously determined “normal image”. I.e. giving a numerical value to what we usually detect with our nose.

The system:

Is composed of a GC that is equipped with two columns in parallel, with different polarities, where the identification is based on Kovats indices and a library with so far 83,600 components. The analysis is typically headspace, with an in-built focusing on a cold trap and narrow bore columns. This therefore also allows the analysis of small components with extremely high sensitivity, down to about 1ppb for most components – and a total time of about 7 min/analysis (chromatography time around 4 min.).

Data processing:

The strongest part of the equipment may well be the AlphaSoft software, which besides the usual data processing software, has a built-in chemometric module that makes the equipment extremely suitable for statistical data processing and chemometry and therefore suitable for QC on foodstuffs, pharmaceuticals or consumables that require a constant component profile. This may eventually reduce or eliminate the use of a sensory panel, and is especially useful if a constant sensory profile is needed over time.

Technical:

The heart of the system is made up as above mentioned with a (micro) GC fitted with two columns 10m x 0.18mm arranged in parallel, and with two FID detectors. The detection is based on Kovats indices and the software is optimized for use of these. The injected components are collected on a cold trap which can be cooled to 0°C and heated to 280°C. The oven can be heated at a rate of 10°C/sec, and therefore allows for fast analysis. The system provides nice and fast chromatography and is applicable not only for the statistical tasks, but also for routine control where a high daily sample flow is necessary.

Read more about the systemt here, or write to Jens Glastrup.