A method and apparatus for two-dimensional gas chromatography (GC), including a valve having first and second positions (P1, and P2), and first through fourth sample flow paths (FP1-FP4). In P1, a first gas sample is collected from a first dimension GC column via FP1, a first pressure source and a first, second dimension GC column are connected via FP2, a second pressure source and a second, second dimension GC column are connected via FP3, and FP4 is disconnected. In P2, the first sample in FP1 is introduced to the second, second dimension GC column via FP1, with aid of the second pressure source, a second gas sample is collected from the first dimension GC column via FP2, the first pressure source and the first, second dimension GC column via FP4 are connected, and FP3 is disconnected.