Development of and Automated Microprocessor Controlled Gas chromatograph Fraction Collector / Olfactometer

Juan P. Salinas and Thomas Hartman, Rutgers University, Center for Advanced Food Technology

John Manos, Christopher Baker and John Manura, Scientific Instrument Services.

The technique of GC fraction collection is useful in odor flavor and chemistry for the isolation and identification of volatile compounds from foods and natural products. It is also used for fractionation and preparation of analytical reference standards from mixtures. Individual constituents from complex systems are often difficult to analyze due to low concentrations that are below the limit of detection of the MS and do not meet the sample quantity required for analysis by other instruments such as IR and NMR. On other occasions high concentrations obscure the spectrum of a minor component. A GC fraction collector can be used to trap and concentrate these individual volatile constituents for rechromatography or for analysis by other analytical instruments.

This report describes the design, construction and operation of an automated gas chromatograph fraction collector/olfactometer. The device allows for the automatic of up to 12 fractions, unattended or as many as desired with assistance. The fractions are trapped at room or subambient temperatures (dry CO2) in glass lined stainless steel tubes, packed with adsorbent material or inert supports (Tenax®, activated carbon, glass beads, etc.). The trapped compounds are eluted from the tubes by either thermal desorption for rechromatography (GC and GC/MS) or solvent extraction for IR, UV, NMR and MS. The instrument is designed to eliminate possible contamination during trapping due to high dead volumes, cold spots, unnecessary hardware, transfer lines, polymers and elastomers, etc. The device is also adapted with a sniff port for flavor/odor characterization.