| 摘要 |
PURPOSE:To compensate and erase the fluctuation of a base line on the high density side of a sample component by a method wherein negative voltage is applied to two of the collectors of a hydrogen flame ionization detector (FID) and the difference between the output signals of the collectors is used. CONSTITUTION:Negative D.C. voltages EA, EB are applied to a collector 1 (sample side) and a collector 2 (reference side) in series with a signal line, respectively. The outputs A, B from the above collectors 1, 2 are selectively sent to synchronous rectifiers 5, 6 by the synchronous operation of a switch SW1 to become D.C. signals and outputted to a terminal a (with waveform shown by Fig. A) and a terminal b (with waveform shown by Fig. B). On the other hand, an output signal (signal of difference between those of the collectors 1 and 2, or A.C. signal) of an operation amplifier 4 which has passed through a capacitor C1 is outputted to a terminal c via an A.C. regenerator 7, a polarity switching device 10 (waveform shown by Fig. C), so that a charomatograph free from the fluctuation of the base line can be obtained on the high density side. |
