Liquid sample introduction system for ion source

A liquid sample introduction system for an ion source which ionizes a liquid sample by supplying the liquid sample to an ionization probe in an ion source and making an atomization-promoting gas blow at the liquid sample exiting from a tip of the ionization probe, the liquid sample introduction system comprising:

• a) a plurality of liquid sample containers, each of which is a hermetically closable container for holding a liquid sample;
• b) a liquid-supply-gas passage having one end connected to a point in a passage for an atomization-promoting gas leading to the ion source, and another end connected to a space above a liquid level in one of the liquid sample containers;
• c) a sample supply passage having one end connected to a space below the liquid level in one of the liquid sample containers and another end connected to the ionization probe;
• and
• d) a passage-switching unit, located in the sample supply passage, for switching the sample supply passage between a communicating state and a closed state,
• where:
• the other end of the liquid-supply-gas passage is branched into a plurality of liquid-supply-gas sub-passages each of which is connected to the space above the liquid level in one of the liquid sample containers;
• the one end of the sample-supply passage is branched into a plurality of sample-supply sub-passages each of which is connected to the space below the liquid level in one of the liquid sample containers;
• and
• the passage-switching unit is a passage-switching valve placed at a branching point of the sample-supply sub-passages, the passage-switching valve having one main port and a plurality of sub-ports to be selectively connected to the main port, where one of the plurality of sub-ports is open to atmospheric pressure, and the plurality of sample-supply sub-passages are connected to the other sub-ports.