A gas transport system includes at least one chemical reactor having at least one inlet and at least one gas outlet and at least one sample introduction unit for delivering the sample into the chemical reactor. The gas transport system at least one carrier gas line fluidly coupled to the chemical reactor inlet for introducing into the chemical reactor carrier gas from a carrier gas source, at least one gas outlet line from the chemical reactor gas outlet, and at least one gas recycling line connected to the gas outlet and/or the gas outlet line by a first gas line junction that is arranged between the chemical reactor and a downstream detection unit on the gas outlet line. The gas transport system is adapted to allow recycling of at least a portion of gas emerging from the chemical reactor outlet back to the chemical reactor via the gas recycling line.