Selective, high speed detection of vapors with analysis of multiple GC-separated portions

A method of rapidly and selectively detecting first and second specific compounds in a gas sample, said compounds being separable by gas chromatography and said first compound having a volatility substantially higher than the volatility of said second compound, comprising:

• trapping vapors of said specific compounds in a vapor concentrator;
• and while flowing a carrier gas through the vapor concentrator, forming and analyzing a first portion of a gas sample containing said first specific compound during a first interval of time and thereafter forming and analyzing a second portion of a gas sample containing said second specific compound during a second interval of time;
• said forming and analyzing of the first portion comprising the steps of (a) flash-heating the vapor concentrator to a first temperature effective to remove volatile materials including said first specific compound from said vapor concentrator with said flow of carrier gas without removing said second specific compound, (b) gas chromatographically (GC)-separating said first portion in a gas chromatograph connected to said vapor concentrator, and (c) detecting said first specific compound in said GC-separated first portion;
• said forming and analyzing of the second portion comprising the steps of (a) flash-heating the vapor concentrator to a second temperature higher than said first temperature to form said second portion, (b) gas chromatographically (GC)-separating said second portion, and (c) detecting said second specific compound in said GC-separated second portion.