The invention generally relates to enclosed desorption electrospray ionization probes, systems, and methods. In certain embodiments, the invention provides a source of DESI-active spray, in which a distal portion of the source is enclosed within a transfer member such that the DESI-active spray is produced within the transfer member.

An ion source is disclosed that alternates between ionizing analytes in a sample by electrospray ionization and impact ionization.

An ion source is disclosed that alternates between ionizing analytes in a sample by electrospray ionization and impact ionization.

Systems and methods for generating digital waveforms with high-resolution duty cycles are disclosed. A smoothed sinusoidal waveform set to a voltage other than ground may be generated and/or received. A rectangular waveform may be generated based on the sinusoidal waveform using a comparator. The rectangular waveform may be utilized to adjust the duty cycle of a current applied to a mass analyzer to improve duty-cycle resolution of a mass analyzer of a mass spectrometer.

Systems and methods for generating digital waveforms with high-resolution duty cycles are disclosed. A smoothed sinusoidal waveform set to a voltage other than ground may be generated and/or received. A rectangular waveform may be generated based on the sinusoidal waveform using a comparator. The rectangular waveform may be utilized to adjust the duty cycle of a current applied to a mass analyzer to improve duty-cycle resolution of a mass analyzer of a mass spectrometer.

The invention generally relates to enclosed desorption electrospray ionization probes, systems, and methods. In certain embodiments, the invention provides a source of DESI-active spray, in which a distal portion of the source is enclosed within a transfer member such that the DESI-active spray is produced within the transfer member.

The invention generally relates to enclosed desorption electrospray ionization probes, systems, and methods. In certain embodiments, the invention provides a source of DESI-active spray, in which a distal portion of the source is enclosed within a transfer member such that the DESI-active spray is produced within the transfer member.

Systems and methods are provided for determining the organic silicon content of petroleum fractions, such as refinery fractions. This can be achieved in part based on performing solvent-enhanced selective filtration on a hydrocarbonaceous sample to substantially remove inorganic silicon from the sample while retaining at least a substantial portion of the organic silicon in the sample. After the solvent-enhanced selective filtration, the organic silicon content of the filtered sample can be determined. The ability to determine the organic silicon content of a sample can be used to identify crude fractions and/or refinery fractions that may cause contamination problems within a refinery while reducing or minimizing the occurrence of false positive tests that could result from detection of inorganic silicon.

A mass spectrometer includes an ion source configured to generate reagent ions; a drift tube configured to cause sample molecules to react with the reagent ions to generate sample ions, the drift tube comprising two sets of electrodes which are identical in structure and symmetrically distributed in a direction perpendicular to a direction of ion drift, each set of electrodes comprising a plurality of curved cell electrodes which are distributed in a same plane and arranged in the direction of ion drift so that the sample ions are generated and drifted within a region between the two sets of electrodes and focused in the direction perpendicular to the direction of ion drift; a power supply device configured to apply, to each of the cell electrodes, a DC voltage changing in the direction of ion drift; and, a mass analyzer configured to perform mass analysis for the sample ions.

The invention proposes a mass spectrometry apparatus for ultraviolet light ionization of neutral lost molecules, and a method for operating same. The mass spectrometry apparatus for ultraviolet light ionization of neutral lost molecules includes a quadrupole tandem special linear ion trap mass analyzer, a vacuum ultraviolet lamp, a lamp front shutter, a gradient vacuum system and other necessary components for the mass spectrometry apparatus. In addition, the invention also proposes a method for operating the apparatus to efficiently store ions, fragment and analyze the ions, perform ultraviolet efficient ionization on lost neutral molecules, and then analyze the ions.