An apparatus for the concentration and analysis of chemical components of a chemical sample that includes a mixture of such components, the apparatus comprising: separation means for separating the components of the sample within a chemical sample fluid stream; conduit means equipped with temperature modulation means, with the conduit means having a receiving port for receiving the chemical sample fluid stream from the separation means and an outlet port for expelling the chemical sample fluid stream, the ports being in fluid communication with each other to allow movement of the fluid stream from the inlet port towards the outlet port, with the temperature modulation means being capable of cooling one or more portions of the conduit means and the portion(s) of the chemical sample fluid stream therein, so as to cause at least decrease of the movement of the portion(s) of the fluid stream, and of allowing warming up of the portion(s) of the chemical sample fluid stream after the cooling so as to resume movement thereof in the conduit means, wherein: a) the conduit means and the temperature modulation means are arranged in such a way as to allow a selected component of the chemical sample fluid stream to be cooled at least twice before expulsion thereof through the outlet port; and b) detector means are provided up-stream of the first cooling portion of the conduit means to detect peak or band information to identify the selected component of the fluid stream; and c) a computer is provided to operate the thermal modulation means to cool the selected component based on the detected peak or band information so as to allow control of the residence time of the chemical sample fluid stream in the cooled portion or portions of the conduit means for analysis thereof, characterized in that: - the conduit means are in the form of a loop comprising a double strand portion, with a single temperature modulator being arranged in the double strand portion in such a way as to allow simultaneous or non-simultaneous first and second coolings of the chemical sample fluid stream before expulsion thereof through the outlet port; and - the temperature modulator is a movable cryogenic trap. separation means for separating the components of the sample within a chemical sample fluid stream; conduit means equipped with temperature modulation means, with the conduit means having a receiving port for receiving the chemical sample fluid stream from the separation means and an outlet port for expelling the chemical sample fluid stream, the ports being in fluid communication with each other to allow movement of the fluid stream from the inlet port towards the outlet port, with the temperature modulation means being capable of cooling one or more portions of the conduit means and the portion(s) of the chemical sample fluid stream therein, so as to cause at least decrease of the movement of the portion(s) of the fluid stream, and of allowing warming up of the portion(s) of the chemical sample fluid stream after the cooling so as to resume movement thereof in the conduit means, wherein: a) the conduit means and the temperature modulation means are arranged in such a way as to allow a selected component of the chemical sample fluid stream to be cooled at least twice before expulsion thereof through the outlet port; and b) detector means are provided up-stream of the first cooling portion of the conduit means to detect peak or band information to identify the selected component of the fluid stream; and c) a computer is provided to operate the thermal modulation means to cool the selected component based on the detected peak or band information so as to allow control of the residence time of the chemical sample fluid stream in the cooled portion or portions of the conduit means for analysis thereof, characterized in that: - the conduit means are in the form of a loop comprising a double strand portion, with a single temperature modulator being arranged in the double strand portion in such a way as to allow simultaneous or non-simultaneous first and second coolings of the chemical sample fluid stream before expulsion thereof through the outlet port; and - the temperature modulator is a movable cryogenic trap. a) the conduit means and the temperature modulation means are arranged in such a way as to allow a selected component of the chemical sample fluid stream to be cooled at least twice before expulsion thereof through the outlet port; and b) detector means are provided up-stream of the first cooling portion of the conduit means to detect peak or band information to identify the selected component of the fluid stream; and c) a computer is provided to operate the thermal modulation means to cool the selected component based on the detected peak or band information so as to allow control of the residence time of the chemical sample fluid stream in the cooled portion or portions of the conduit means for analysis thereof, - the conduit means are in the form of a loop comprising a double strand portion, with a single temperature modulator being arranged in the double strand portion in such a way as to allow simultaneous or non-simultaneous first and second coolings of the chemical sample fluid stream before expulsion thereof through the outlet port; and - the temperature modulator is a movable cryogenic trap.