A device for ion chromatography comprises a tube with an inlet opening and an outlet opening and an inner diameter from about 40 microns to about 10 microns. There is an aperture through one side of the tube into a lumen of the tube. At least a portion of the inner surface of the tube has a first charge. An ion exchange barrier covers the aperture on an outside surface of the tube. The inner surface of the tube, from the inlet opening to the aperture, is coated with ion exchange particles having a diameter ranging from about 30 nm to about 200 nm. The ion exchange particles have a second charge opposite the first charge. The inner surface of the tube, from the outlet opening to the aperture, is not coated with ion exchange particles.

A secondary ultrasonic nebulisation device is disclosed comprising: a liquid sample delivery capillary; a sample receiving surface arranged for receiving a liquid sample from the capillary; and an ultrasonic transducer configured for oscillating the surface so as to nebulise the liquid sample received thereon, wherein the device is configured such that the oscillations of the surface by the ultrasonic transducer cause charged droplets and/or gas phase ions to be generated from the sample.

A GC/MS measurement under an ionization by an electron ionization method is performed for a target sample (S1). Peaks are detected on a chromatogram based on obtained data, and a mass spectrum corresponding to each peak is compared with a compound database to identify a compound (S2-S4). A compound identified with a low degree of similarity is extracted as the measurement compound. For this compound, a measurement window including the retention time of a peak corresponding to the compound is set, and a control program for performing an ionization by a chemical ionization method only within the measurement window is created (S5-S8). According to this control program, a GC/MS measurement for the target sample is performed, with the device controlled so that a reagent gas is supplied into an ionization chamber and a filament for generating thermions is energized within the measurement window, whereas the supply of the reagent gas is discontinued and the filament is deenergized within time ranges other than the measurement window (S9). Since no reagent-gas ion is generated within the time ranges other than the measurement window, the adhesion of the ions to the inside of the ionization chamber and other locations will be reduced. Accordingly, a stable measurement can be performed for a long period of time.

A secondary ultrasonic nebulisation device is disclosed comprising: a liquid sample delivery capillary; a sample receiving surface arranged for receiving a liquid sample from the capillary; and an ultrasonic transducer configured for oscillating the surface so as to nebulise the liquid sample received thereon, wherein the device is configured such that the oscillations of the surface by the ultrasonic transducer cause charged droplets and/or gas phase ions to be generated from the sample.

A secondary ultrasonic nebulization device is disclosed comprising: a liquid sample delivery capillary; a sample receiving surface arranged for receiving a liquid sample from the capillary; and an ultrasonic transducer configured for oscillating the surface so as to nebulize the liquid sample received thereon, wherein the device is configured such that the oscillations of the surface by the ultrasonic transducer cause charged droplets and/or gas phase ions to be generated from the sample.

A device for ion chromatography comprises a tube with an inlet opening and an outlet opening and an inner diameter from about 40 microns to about 10 microns. There is an aperture through one side of the tube into a lumen of the tube. At least a portion of the inner surface of the tube has a first charge. An ion exchange barrier covers the aperture on an outside surface of the tube. The inner surface of the tube, from the inlet opening to the aperture, is coated with ion exchange particles having a diameter ranging from about 30 nm to about 200 nm. The ion exchange particles have a second charge opposite the first charge. The inner surface of the tube, from the outlet opening to the aperture, is not coated with ion exchange particles.

A GC/MS measurement under an ionization by an electron ionization method is performed for a target sample (S1). Peaks are detected on a chromatogram based on obtained data, and a mass spectrum corresponding to each peak is compared with a compound database to identify a compound (S2-S4). A compound identified with a low degree of similarity is extracted as the measurement compound. For this compound, a measurement window including the retention time of a peak corresponding to the compound is set, and a control program for performing an ionization by a chemical ionization method only within the measurement window is created (S5-S8). According to this control program, a GC/MS measurement for the target sample is performed, with the device controlled so that a reagent gas is supplied into an ionization chamber and a filament for generating thermions is energized within the measurement window, whereas the supply of the reagent gas is discontinued and the filament is deenergized within time ranges other than the measurement window (S9). Since no reagent-gas ion is generated within the time ranges other than the measurement window, the adhesion of the ions to the inside of the ionization chamber and other locations will be reduced. Accordingly, a stable measurement can be performed for a long period of time.

A secondary ultrasonic nebulisation device is disclosed comprising: a liquid sample delivery capillary; a sample receiving surface arranged for receiving a liquid sample from the capillary; and an ultrasonic transducer configured for oscillating the surface so as to nebulise the liquid sample received thereon, wherein the device is configured such that the oscillations of the surface by the ultrasonic transducer cause charged droplets and/or gas phase ions to be generated from the sample.