Ionization probe
In the ionization probe, an assist gas nozzle, coaxial with a nozzle, is provided around a nozzle that discharges a liquid sample. A housing inside which is formed an annular assist gas channel is provided around the assist gas nozzle. A gas inlet for introducing gas into the assist gas heating channel and gas outlet for feeding gas from channel to assist gas nozzle are provided at opposite locations across the center of the channel. Gas introduced into the assist gas heating channel is heated by a substantially annular heater, and high temperature gas is discharged through gas discharge hole of the assist gas nozzle. The heater and the channel through which high temperature gas flows are arranged solely at the tip part of the ionization probe, so thermal insulation of the probe base part can be easily accomplished.
1. An ionization probe for atomizing a liquid sample and ionizing components contained in said sample, comprising:
a) a nozzle which atomizes a liquid sample;
b) an assist gas nozzle comprising an open part provided around the tip of the aforementioned nozzle, for spraying assist gas in the same direction as the direction of atomization of liquid sample from the aforementioned nozzle;
c) an annular assist gas channel arranged so as to surround the periphery of the tip part of said assist gas nozzle and having a gas outlet which communicates with said assist gas nozzle; and
d) an annular heater arranged in said annular assist gas channel, wherein at least one portion of the annular shape or in the circumferential direction of the annular heater is missing;
wherein the at least one missing portion of the annual heater is aligned with a gas inlet gas inlet which admits assist gas into said annular assist gas channel and is aligned with the gas outlet which communicates with said assist gas nozzle.
2. The ionization probe as described in claim 1 ,
wherein said gas outlet is formed at one circumferential location of said annular assist gas channel, the at least one missing portion of the annual heater comprises two portions, and the gas inlet which admits assist gas into said annular assist gas channel is formed at a position opposite said gas outlet across the center of the ring of said channel.
3. The ionization probe as described in claim 2 ,
wherein said heater is a micro-sheath heater, the heater line of said micro-sheath heater is wound on both sides with the longitudinal center as a boundary, so as to form two heating parts, and said heating parts are arranged respectively in two channels extending from said gas inlet to said gas outlet within said annular assist gas channel.
4. The ionization probe as described in claim 2 ,
wherein said assist gas nozzle is provided at a location displaced from the center of the ring of said annular assist gas channel in the direction of said gas outlet.
5. The ionization probe as described in claim 4 ,
wherein said heater is a micro-sheath heater, the heater line of said micro-sheath heater is wound on both sides with the longitudinal center as a boundary, so as to form two heating parts, and said heating parts are arranged respectively in two channels extending from said gas inlet to said gas outlet within said annular assist gas channel.
6. The ionization probe as described in claim 1 ,
wherein said assist gas nozzle is provided at a location displaced from the center of the ring of said annular assist gas channel in the direction of said gas outlet.
7. The ionization probe as described in claim 6 ,
wherein said heater is a micro-sheath heater, the heater line of said micro-sheath heater is wound on both sides with the longitudinal center as a boundary, so as to form two heating parts, and said heating parts are arranged respectively in two channels extending from said gas inlet to said gas outlet within said annular assist gas channel.
8. The ionization probe as described in claim 1 , wherein said assist gas nozzle surrounds said nozzle, and said annular assist gas channel surrounds said assist gas nozzle.
9. The ionization probe as described in claim 1 , wherein said assist gas which introduced from the gas inlet flows circumferentially inside of said annular assist gas channel.