| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for separating an ion signal corresponding to a specimen from signals caused by interferences. SOLUTION: A method is provided for reducing isobaric interferences caused by transmitting ions from an ion source through an ion transmission device and a quadrupole collision cell into an analyzing mass spectrometer, in which the collision cell is operated with a pass band for rejecting intermediate ions which would otherwise tend to react to form isobaric interferences. Preferably ammonia is used as a reaction gas in the collision cell. Depending on the chemical species involved and its chemical property, the collision cell may be operated to set a low-mass cutoff at an appropriate level, or more usually, the pass band will have both high and low-mass cutoffs determined by applying both an RF and a DC to the collision cell. The collision cell may also be operated with a pass band to transmit ions into a time-of-flight (TOF) mass spectrometer, thus limiting the mass range of ions entering the TOF to improve the duty cycle of the TOF. COPYRIGHT: (C)2007,JPO&INPIT |
