Frequently Asked Questions

Why HERACLES is called an Electronic Nose?

This instrument allows to perform the analysis of volatile organic compounds and odors, as a global sensory fingerprint, like the human sense of smell

What type of sample can be analyzed with HERACLES?

Solid and liquid products can be analyzed by weighing a fixed amount of sample in a vial. Generally, no sample preparation is required. 

HERACLES can work in headpsace or liquid injection modes.

Gas samples can also be analyzed using an optional gas configuration : plastic bags filled with gas can be sampled using a pump.

Why use an autosampler with HERACLES?

To guarantee reproducible analytical conditions in sample incubation and injection, therefore to guarantee reliable results, and to automate the run of a sequence of several samples and increase analysis throughput.

What type of injection can be performed with HERACLES Fast-GC e-nose?

Both headspace an liquid injections are possible.

Direct liquid injection can allow higher sensitivity for low volatile molecules, such as those found in essential oils or alcohol extracts. However, it is not recommended for odor analyses, as it tends to underestimate the amount of volatile compounds in the headspace. Sensitivity for highly volatile compounds is much lower, and liquids containing high amounts of non-volatile compounds can pollute the liner. Therefore, liquid injection should be reserved for fully volatile or low-volatile samples.

What types of gases are used with HERACLES e-nose?

Pure dry air (water < 5ppm and hydrocarbons < 5ppm) and hydrogen (purity > 99.999%) for FIDs. It is recommended to uses gases produced from a FID station.

Why HERACLES features a trap and 2 columns?

A built-in Tenax trap that can be cooled down to 5°C is integrated in the instrument in order to increase the sensitivity of the system. The sample is focused on the trap that is then thermodesorbed very quickly onto the 2 columns in parallel. The two columns of different polarities in parallel allow avoiding coelution. Two compounds that are not separated on the first column will be separated on the second column. 

Is it possible to change the trap?

The built-in trap cannot be changed by the user. It requires the intervention of a technical specialist certified by Alpha MOS. The choice of Tenax materials is explained by the fact that it is a good generic and robust material. On the current version of Heracles there is no possibility to use another type of trap material.

How often columns have to be changed and who can do it?

In normal use, HERACLES can be operated up to 5 years with more than 100 000 injections, without having to change the columns. 

The columns have to be changed by an Alpha MOS technical support or representative.

How often should HERACLES be calibrated?

It is recommended to run an alkane calibration every week. 

What consumables are necessary for HERACLES use?

Main consumables are vials, caps, septa, syringes, filters and diagnostic solutions. All consumables needed are specified in our Consumables & Accessories Catalog.

What maintenance operations are required with HERACLES?

Routine maintenance operations consist in changing the injection septum every 200 injections and make a weekly test to check the performance of the columns.

A yearly preventive maintenance is recommended. This intervention consists in replacing some filters and cartridges on gas sources to guarantee purity, in changing igniters and also checking and cleaning the autosampler. If the system is used intensively (more than 5 000 samples a year), we recommend to perform 2 maintenances a year. Alpha MOS offers different maintenance service packages.

What are the main applications of HERACLES? Which ones are not possible?

- Conformity/quality control on the overall odor profile for batch-to-batch consistency 

- Defect detection

- Quantification of the concentration of a target compound or a sensory score (in correlation with sensory panel results)

- Benchmarking of competitive products on sensory profile

- Shelf life follow up

- Odor masking testing

- Process monitoring to check the consistency of sensory features

- Cleaning In Place Efficiency testing

Not possible: analysis of TCA, boar taint (indole, scatol, etc), mineral oils contamination, contamination of beef by horse meat

What type of sensors are used in ASTREE e-tongue?

Astree uses 7 ChemFET sensors. When in contact with soluble molecules, a change of conductivity (potentiometric difference) is measured between each sensor and a reference electrode. Each sensor is sensitive to several molecules, with particular sensitivities to some molecules. For example, some sensors are more particularly sensitive to molecules responsible for the sweet taste; other sensors are more sensitive to molecules typical of acid taste, etc.

What is the usual life time of ASTREE sensors?

Sensors life time depends on the application and on how the sensors are handled. Typically, in normal conditions of use, handling and storage, sensors can be used for several months. 

What type of samples can be analyzed with ASTREE?

ASTREE e-Tongue analyzes aqueous solutions; this means that aqueous samples can be directly analyzed or solid samples after dissolution in a liquid matrix (filtering can be needed in case there would remain particles).

What products are not recommended for analysis with ASTREE?

Sensors are compatible with liquid matrices. 

It is recommended to avoid high concentration of solvents.

• List of solvents which can be used without damage on Astree sensors: propanol, ethanol (up to 50 %).

• Range of solvent viscosity

 PEG 400 10% in water and PEG 400 65% in water can be analyzed without any specific precaution.

Analysis of PEG 400 more than 65% in water is not recommended

•Do not use solvents such as: Ketones (acetone), chloro (chloroform, dichloromethane), nitriles (acetonitrile), H2SO4, HNO3.

How often should ASTREE be calibrated?

Sensors calibration is necessary when the instrument is started and before each series of analysis.

Can ASTREE perform quantitative analysis?

Quantification models can be set up by correlating Astree measurements with:

- another analytical technique (e.g. HPLC or GC), to predict a concentration in new samples

- sensory panel scorings on sensory attributes to determine a sensory descriptor score in new samples.

What is the typical run time with ASTREE?

For 1 sample: 3 minutes between 2 analyses.

For 10 samples: acquisition time is around 3 hours.

What consumables are necessary for ASTREE use?

The use of ASTREE requires very few consumables: only diagnosis solutions. Beakers used for the analysis can be washed and re-used; sensors can be used for months.

What maintenance operations are required with ASTREE?

Routine maintenance is very limited: checking and cleaning of sensors, cleaning of the reference electrode.

The annual maintenance consists in checking the autosampler and sensors, and replaceing sensors only if needed.

What samples can be analyzed with IRIS?

Thanks to its large measurement surface and depending on the focal length of the lens used, IRIS can analyze large products or small objects with dimensions up to 54 x 40 cm, and down to 0.01 mm2.

IRIS can assess both uniform or complex surfaces. No sample preparation is required.

Is it possible to change lenses?

In standard configuration IRIS is delivered with one lens of fixed focal length (5mm). The lens can be easily changed to 4-6-8-12-16-25 mm to increase optical zoom. For all lens es above 12 mm a specific color checker is provided to calibrate the system.

What is the resolution of the camera?

5 MPx (2588 x 1942)

What type of lighting is used in IRIS?

The e-eye uses LED lighting (5000K, corresponding to daylight perception, D50 compliant), both front-lighting and back-lighting to avoid any shadow effect. The 2 lightings can be switched on/off individually. The LED life time is more than 40 000 hours.

What consumables are necessary for IRIS use?

Color checkers and plates only if they have to be replaced.

What maintenance operations are required with IRIS?

No maintenance is needed except regular cleaning of the plate and objective.

What are the main applications of IRIS? Which ones are not possible?

- Conformity/quality control on the overall visual aspect - Batch to batch consistency

- Defect detection and quantification of defect proportion

- Quantification of the proportions of several ingredients in a mixture (with prior separation of the discrete elements, done manually)

- Benchmarking of competitive products on visual aspect

- Shelf life follow up

- Process monitoring to check the consistency of the visual aspect

Not possible: 3D (e.g. liquids in bottles), online analysis, liquids and powder analysis.