Dow Global Technolgoies LLC

Rohm and Haas Company

Rohm and Haas Chemicals LLC

Ronda L Gras

Jim C Luong

Warren E Smith

Raymond John Swedo

George David Green

A gas chromatographic method for detecting a marker compound in a fuel by (a) introducing a sample of fuel into a first capillary column coated with a stationary phase based on polydimethylsiloxane and allowing the sample to flow through the first column to produce a first effluent; (b) allowing the first effluent to pass through a detector and identifying a retention time range in it which includes a retention time of the marker compound; (c) introducing only a portion of the first effluent stream which is within the retention time range into a second capillary column coated with either (i) an ionic sorbent or (ii) a polyethylene glycol, and allowing said portion to flow through the second capillary column to produce a second effluent stream; and (d) allowing the second effluent to pass through a detector; wherein the marker compound has formula Ar(R)(OR)and is present in the fuel at a level from 0.01 ppm to 100 ppm.

Analytical method for detecting fuel markers

A gas chromatographic method for detecting a first marker and a second marker in a fuel in two channels: (i) a first capillary column coated with polysiloxane and a second capillary column coated with polyethylene glycol; and (ii) a third capillary column coated with polymethylphenylsiloxane and a fourth deactivated capillary column. The steps are: (a) introducing a first sample into the first column to produce a first effluent; (b) introducing only a portion of the first effluent into the second column to produce a second effluent; (c) allowing the second effluent to pass through a mass spectrometer; (d) introducing a second sample into the third column to produce a third effluent; (e) introducing only a portion of the third effluent into the fourth column to produce a fourth effluent; (f) allowing the fourth effluent to pass through a mass spectrometer.

A method for marking a petroleum hydrocarbon or a liquid biologically derived fuel by adding to the petroleum hydrocarbon or liquid biologically derived fuel at least one compound having formula Ar(R)(OR), wherein Ar is an aromatic ring system having from six to twenty carbon atoms, Ris C-Calkyl or C-Calkenyl, Ris C-Calkyl or C-Calkenyl, m is an integer from zero to five and n is an integer from one to three; wherein each compound of formula Ar(R)(OR)is present at a level from 0.01 ppm to 100 ppm.

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Edmonton, Canada

Ronda L Gras