Spray ionization device

A spray ionization device, comprising:

• a first tube including a first channel through which a liquid can flow, the first tube including a first outlet for ejecting the liquid at one end;
• a second tube surrounding the first tube with a gap and including a second channel through which a gas can flow, the second tube including a second outlet at the one end, the second channel being defined by an outer circumferential surface of the first tube and an inner circumferential surface of the second tube;
• and
• an electrode which extends within the first channel of the first tube from an opposite end to the first end, and is arranged so that a leading end is the same position as the first outlet or further toward the opposite end than the first outlet, the electrode being capable of applying voltage to the liquid by way of a power source connected to the electrode, wherein
• the second channel includes a constriction portion, and a channel area of the second channel progressively decreases from the opposite end to the constriction portion,
• at the one end, the second outlet is arranged further downstream than the first outlet, at least a portion of the inner circumferential surface of the second tube has a diameter that progressively decreases toward the second outlet, and a diameter of the inner circumferential surface of the second outlet is equal to or greater than an opening diameter of the first outlet, and
• electrically charged droplets of the liquid can be ejected from the second outlet,
• the spray ionization device, further comprising:
• a third tube between the first tube and the second tube, the third tube surrounding the first tube and including a third outlet at the one end, wherein
• the second channel through which the gas can flow is defined by an outer circumferential surface of the third tube and the inner circumferential surface of the second tube,
• at the one end, a tip of the third tube is arranged further toward the opposite end than the first outlet, and
• at a tip at the one end of the third tube, a gap between an inner circumferential surface of the third tube and the outer circumferential surface of the first tube is blocked.