Gas chromatography (GC) with flame ionization detection (FID) is still an important and relatively inexpensive problem solving analytical method despite the maturity of this technique. Although the FID is a sensitive and rugged detector, it does not provide qualitative identification of the separated components. We have initiated a dynamic GC stationary phase modification research program to permit on-column reaction chemistry which can identify certain classes of organic compounds. In particular, we have adopted the Leuckhart reaction to identify the presence of carbonyl compounds. This reaction between formamide and an aldehyde or ketone will generate the N-formyl derivative at elevated temperature, preferentially greater than 165 o C.
A five-microliter injection of a 10% formamide in ethanol solution was made and the column (30 m x 0.53 mm ID, 0.5 micron film thickness, 65%dimethyl/35% diphenyl polysiloxane) conditioned isothermally at a low temperature for a set time. Upon injection of alkyl or aromatic ketones or aldehydes, a second small peak was distinguished with about a 30 second earlier retention time from the staring compound using the same temperature program (40C 5min hold, 30C/min to 260, hold 5 min). No such second peak was noted upon injection of either decane or ethylbenzene on the formamide treated column using the same temperature program. Some baseline drift is noted as the nonvolatile formamide gradually comes off the column but the response is minimal because formamide, with only a single C-H bond, has a weak FID response. Optimization of the formamide column coating procedure and versatility of the response for other carbonyl compounds are being ascertained.
Author(s): Damian Clucas, Biochemistry and Biology Major
Advisor(s): Neil Danielson, Department of Chemistry and Biochemistry
Bolaji Ayeseni, Department of Chemistry and Biochemistry
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