The invention generally relates to methods of analyzing crude oil. In certain embodiments, methods of the invention involve obtaining a crude oil sample, and subjecting the crude oil sample to mass spectrometry analysis. In certain embodiments, the method is performed without any sample pre-purification steps.

The degree of ion dissociation which occurs within a first intermediate vacuum chamber (212) maintained at a comparatively low degree of vacuum depends not only on the amount of energy of the ion but also on the size and other properties of the ion. Accordingly, a predetermined optimum level of DC bias voltage is applied to an ion guide (24) so as to create, within the first intermediate vacuum chamber (212), a DC electric field which barely induces the dissociation of an ion originating from a target compound in a sample while promoting the dissociation of an ion originating from a foreign substance which will form a noise signal in the observation of the target compound. The optimum DC bias voltage is previously determined by creating extracted ion chromatograms based on data collected under various DC bias voltages and evaluating the SN ratio using the chromatograms. Consequently, the accuracy and sensitivity of the quantitative determination is improved as compared to a conventional system in which only the signal strength of the target compound is considered.

Ions provided from an ion source are separated ions into a plurality of different ion groups according to at least one ion property. At least some of the different ion groups are stored in an ion storage array, which comprises a plurality of independently operable storage cells, each storage cell being arranged to receive and store a different ion group. A controller is programmed to cause selective switching of each of the storage cells between an ion receiving mode and an ion storage mode, and between the ion storage mode and an ion release mode. In particular, the switching of each storage cell is controllable independently of the switching of any of the other storage cells. Upon release from a respective storage cell of the array, ions are provided to one or more mass analyzers for subsequent analysis.

A high-voltage power source for applying high voltage to a nozzle of an ESI ion source includes a charge release assistant section (26) including switch circuits (62 and 65) and other elements for forcing electric charges accumulated at output terminals to be discharged in a polarity-switching operation, whereby the positive/negative switching of the polarity of the output voltage can be quickly performed. In the mass spectrometer according to the present invention, for example, when the voltage applied to the nozzle needs to be changed from Vi to V.sub.2 (where V.sub.1 and V.sub.2 are positive, and V.sub.1>V.sub.2), a voltage control section (20) under the command of a main controller (9) operates a positive voltage generation section (21) and negative voltage generation section (23) so as to temporarily provide a negative output voltage. After a predetermined period of time, the voltage control section operates the positive voltage generation section (21) and negative voltage generation section (23) so as to provide voltage V.sub.2. If the voltage was simply changed from V.sub.1 to V.sub.2, the voltage would decrease slowly and require considerable time for the change. The positive/negative switching of the polarity induces the discharging of the electric charges accumulated at the output terminals, and consequently, the voltage-switching operation from V.sub.1 to V.sub.2 is quickly performed.

An automated method of monitoring a state of an analyzer is provided including a mass spectrometer (MS) with an electrospray ionization (ESI) source coupled to a liquid chromatography (LC) stream, including monitoring an electrospray ionization current of the ESI source and identifying a condition of multiple conditions of the analyzer based on the monitored ionization current of the ESI source, one of the conditions being a presence of a dead volume in a liquid chromatography stream of the analyzer downstream of an LC column of the LC stream.

The present disclosure pertains to method and system of characterizing a protein using an electrospray ionization source.

Systems and methods are provided for maximizing the data acquired from a sample in a mass spectrometry imaging experiment. An ion source device is instructed to produce and transmit to a tandem mass spectrometer a plurality of ions for each location of two or more locations of a sample. A mass range is divided into two or more mass window widths. For each location of the two or more locations, the tandem mass spectrometer is instructed to fragment the plurality of ions received for each location using each mass window width of the two or more mass window widths and to analyze resulting product ions. A product ion spectrum is produced for each mass window width, and a plurality of product ion spectra are produced for each location of the two or more locations.

A device and method are disclosed to apply ESI-based mass spectroscopy to submicrometer and nanometer scale aerosol particles. Unipolar ionization is utilized to charge the particles in order to collect them electrostatically on the tip of a tungsten rod. Subsequently, the species composing the collected particles are dissolved by making a liquid flow over the tungsten rod. This liquid with dissolved aerosol contents is formed into highly charged droplets, which release unfragmented ions for mass spectroscopy, such as time-of-flight mass spectroscopy. The device is configured to operate in a switching mode, wherein aerosol deposition occurs while solvent delivery is turned off and vice versa.

A mass spectrometer is disclosed wherein highly charged fragment ions resulting from Electron Transfer Dissociation fragmentation of parent ions are reduced in charge state within a Proton Transfer Reaction cell by reacting the fragment ions with a neutral superbase reagent gas such as Octahydropyrimidolazepine.

A mass spectrometer according to one aspect of the present invention includes an ion source (31), a mass separator (32), and a detector (33), the mass spectrometer further including: a parameter optimization unit (531, 532, 533) configured to optimize a parameter value using a Bayesian optimization method based on a result obtained by making measurements while changing values of device parameters including a plurality of parameters that affects ionization efficiency in the ion source (31), a display processor (536) configured to display a sensitivity model which is a posterior distribution indicating a relationship between a plurality of parameters in all or some of the device parameters and signal strength estimated during the optimization of the device parameters, expressing as a graph like a heat map or an array of a plurality of the graphs on a display unit (7), and to sequentially update the sensitivity model, and a file creation unit (535) configured to a user to designate a position on the displayed graph, and to create a method file containing a measurement condition used for sample measurement, based on a combination of values of parameters corresponding to the designated position.