A method of ionising a sample is disclosed comprising nebulising a sample which includes first biomolecules such as bovine insulin comprising one or more disulphide (S—S) bonds. A stream of droplet or charged droplets comprising one or more disulphide (S—S) bonds is directed so as to impact upon a target (106) or electrode so as to cause the breaking of a portion of the disulphide bonds. Alternatively, charged droplets may pass through an electric field region determined by an electrode (106) arranged downstream of a nebuliser or electrospray probe and an ion inlet (104) of a mass spectrometer so as to cause the breaking of a portion of the disulphide bonds.

The present invention comprises novel methods of continuously monitoring the performance of an atmospheric pressure ionization (API) system. The methods of the invention allow for improved quality monitoring of the processes that leads to the formation of ions at atmospheric pressure. The methods of the invention further allow for continuously monitoring for the quality of the ion formation process in API without the addition of extraneous material (such as labelled compounds or control known compounds) to the system being monitored.

The probe drive unit (21) collects a sample (8) at the tip of the probe (6) by lowering and raising the probe (6) under the control of the control unit (25). After that, the high voltage generating unit (20) applies a high voltage whose voltage value increases in a slope shape to the probe (6), and meanwhile, the mass spectrometry unit behind the capillary tube (10) performs product ion scan measurements on the two-step probe voltage, and the mass spectrum data obtained in each measurement is stored in the first and the second probe voltage corresponding data storage units (301 and 302). When the ionization efficiencies of the plurality of types of components contained in the sample (8) have a probe voltage dependence, ion peaks derived from different types of components appear in the two mass spectra. Thus, a plurality of types of components contained in the sample can be roughly separated, and the identification performance based on the mass spectrum and the quantitative performance based on the chromatogram can be improved.

Provided is an ionization method for ionizing a sample 21 adhered to a tip of a probe 11 that is electrically conductive, by applying an ionization voltage to the probe 11 to electrically charge the sample 21. The ionization method includes: subjecting the probe 11 to treatment to make a surface of the probe 11 homogenous; causing adhesion of the sample 21 to the tip of the probe 11; and ionizing the sample 21 by applying the ionization voltage to the probe 11 to electrically charge the sample 21. The treatment for making the surface of the probe 11 homogenous can be implemented by, for example, causing corona discharge at the probe 11.

Systems and methods for atmospheric pressure chemical ionization are provided herein. In various aspects, the APCI apparatus, systems, and methods can provide an asymmetric sample spray into a vaporization chamber asymmetrically (e.g., off axis from the longitudinal axis of the vaporization chamber) so as to increase the interaction of the molecules in the sample spray with the vaporization chamber's sidewalls (and expose more of the molecules to the heat generated thereby), which can thereby result in improved consistency and/or efficiency of ion formation, and/or increased sensitivity relative to conventional APCI techniques.

The invention generally relates to systems including nanoelectrospray ionization emitters in a movable array format in which the emitters can be loaded, singly or simultaneously, through their narrow ends using a novel dip and go method based on capillary action, taking up sample from an array. The sample solutions in each emitter can be electrophoretically cleaned, singly or simultaneously, by creating an inductive electric field that moves interfering ions away from the narrow end of the capillary. Subsequent to cleaning, the emitters are supplied with an inductive electric field that causes electrospray into a mass spectrometer allowing mass analysis of the contents of the emitter.

The invention relates to the detection of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In a particular aspect, the invention relates to methods for detecting DHA and EPA by mass spectrometry and kits for carrying out such methods.

In an embodiment of the present ambient ionization experiment, the abundance of background chemicals relative to ions of interest is decreased by pulsing the carrier gas used to generate the excited species directed at the sample. The excited species are stepwise directed at the sample reducing the overall abundance of background chemicals introduced into the ionizing region. In an embodiment of the present ambient ionization experiment, the combination of stepping the sample in front of the excited species and pulsing the carrier gas used to generate the excited species increases the sensitivity of detection.

The present invention provides dielectric barrier discharge ionization, including a dielectric barrier discharge tube and an electrode pair consisting of a first electrode and a second electrode. At least a portion of the dielectric barrier discharge tube is provided between the first electrode and the second electrode. The electrode pair can ionize the sample after the power is turned on. The dielectric barrier discharge tube is in communication with a vacuum portion. The pressure range in the dielectric barrier discharge tube is 0.01 to 100 Pa. The dielectric barrier discharge ionization provided by the invention remedies the defects of existing low-pressure ion sources in the pressure range, and provides the low-pressure ion source with high ionization ability, high versatility and simple devices.

The invention generally relates to ion generation using modified wetted porous materials. In certain aspects, the invention generally relates to systems and methods for ion generation using a wetted porous substrate that substantially prevents diffusion of sample into the substrate. In other aspects, the invention generally relate to ion generation using a wetted porous material and a drying agent. In other aspects, the invention generally relates to ion generation using a modified wetted porous substrate in which at least a portion of the porous substrate includes a material that modifies an interaction between a sample and the substrate.