After GC separation, the SIM Olfactory Detector (OFD) is used to record odor associations of an eluted substance and its intensity in function of time. Therefore, a capillary transfers the eluate of the GC column from the oven to the “sniffing port”. This is a glass cone at the outside end of the capillary, where the tester can “sniff” the olfactory impressions of the compounds. The OFD consists of a heatable transfer line without cold spots that is absolutely olfactory neutral, a humidifier that prevents the nasal mucosa from drying out, and a device for simultaneous detection with other GC detectors.
The SIM olfactometric sensors have been developed for Agilent Technologies Chromatographic Systems 6890, 7890 and 7820, being fully integrated into the chassis of the GC or GC/MSD.
Developing the SIM OFD, a high value was set on the following prerequisite conditions that allow optimal and interference-free interpretation of the olfactory impressions:
- Absolutely olfactory neutrality of all used components so that the olfactory perception of the eluted substances is not disturbed.
- Heatable transfer line without „cold spots“ for the correct sniffing of high boiling compounds.
- Comfortable working position is enabled by the sniffing port which is vertically adjustable to individual requirements.
- Humidified air (see water bottle sitting above the sniffing port holder) is mixed into the glass cone to prevent the nasal mucosa from drying out. For this also an odorless tube is used.
- Simultaneous detection with other GC detectors (e.g. FID, MSD, ECD).
- The Microfluidic-Splitters (with/without make-up gas, Deans-switch) use Agilent Capillary Flow Technology that gives you the ability to precisely divert the gas flow pneumatically.
