| 摘要 |
The degree of ionic dissociation occurring in a first intermediate vacuum chamber (212) having a relatively low degree of vacuum is energy dependent and also depends upon such characteristics as the size of the ions. Therefore, a predetermined optimum DC bias voltage is applied to an ion guide (24) in order to form, in the first intermediate vacuum chamber (212), a DC electric field whereby ions originating from the target compound in a sample are not significantly dissociated and dissociation of ions originating from impurities which cause noise during observation of the target compound is promoted. The optimum DC bias voltage is calculated in advance by evaluating the SN ratio using an extraction ion chromatogram based on data collected under conditions of varied DC bias voltages. The precision or sensitivity of quantitative determination is thereby further enhanced relative to the prior art, in which only the signal strength of the target compound is considered. |
