471results about How to "Improve ionization efficiency" patented technology

The invention presents a method for examining genetic material (deoxyribonucleic acid, DNA) to detect the presence of pre-known mutations, especially single nucleotide polymorphisms (SNP), using mass spectrometry with ionization by matrix-assisted laser desorption (MALDI). The invention uses nucleoside triphosphates with modified sites for the method of primer extension in a duplicating, enzymatic reaction and at least partially removal of primers from the extension product, in combination with product neutralization by chemical treatment of the modified sites, so that the resulting DNA products can be, by using special matrix materials, preferredly ionized in an adduct-free form over other constituents in the reaction solution without any further cleaning. The method is particularly suitable for simultaneous identification of several mutations by multiplexing.

An Atmospheric Pressure Chemical Ionization (APCI) source interfaced to a mass spectrometer is configured with a corona discharge needle positioned inside the APCI inlet probe assembly. Liquid sample flowing into the APCI inlet probe is nebulized and vaporized prior to passing through the corona discharge region all contained in the APCI inlet probe assembly Ions produced in the corona discharge region are focused toward the APCI probe centerline to maximize ion transmission through the APCI probe exit. External electric fields penetrating into the APCI probe exit end opening providing additional centerline focusing of sample ions exiting the APCI probe. The APCI probe is configured to shield the electric field from the corona discharge region while allowing penetration of an external electric field to focus APCI generated ions into an orifice into vacuum for mass to charge analysis. Ions that exit the APCI probe are directed only by external electric fields and gas flow maximizing ion transmission into a mass to charge analyzer. The new APCI probe can be configured to operate as a stand alone APCI source inlet probe, as a reagent ion gun for ionizing samples introduced on solids or liquid sample probes or through gas inlets in a multiple function ion source or as the APCI portion of a combination Electrospray and APCI multiple function ion source. Sample ions and gas phase reagent ions are generated in the APCI probe from liquid or gas inlet species or mixtures of both.

The invention relates to method and apparatus for production of gaseous ions from components of a condensed phase sample and analysis thereof, wherein one or more liquid jet(s) is / are directed to the surface of the sample to be investigated, where the impact of the liquid jet on the sample surface produces droplets carrying sample particles which are turned into gaseous ions via the evaporation of liquid or, if desired, by a subsequent ionization after the evaporation and the obtained sample particles are analyzed by a known method.

This invention describes an apparatus and method with a combined primary electrospray and secondary electrospray ionization source used to enhance ionization efficiency. The solid phase as well as liquid phase sampling, ionization, and detection is described.

The current invention involves a desorption corona beam ionization source / device for analyzing samples under atmospheric pressure without sample pretreatment. It includes a gas source, a gas flow tube, a gas flow heater, a metal tube, a DC power supply and a sample support / holder for placing the samples. A visible corona beam is formed at a sharply pointed tip at the exit of the metal tube when a stream of inert gas flows through the metal tube that is applied with a high DC voltage. The gas is heated for desorbing the analyte from solid samples and the desorbed species are ionized by the energized particles embedded in the corona beam. The ions formed are then transferred through an adjacent inlet into a mass spectrometer or other devices capable of analyzing ions. Visibility of the corona beam in the current invention greatly facilitates pinpointing a sampling area on the analyte and also makes profiling of sample surfaces possible.

Atmospheric pressure, intermediate pressure and vacuum laser desorption ionization methods and ion sources are configured to increase ionization efficiency and the efficiency of transmitting ions to a mass to charge analyzer or ion mobility analyzer. An electric field is applied in the region of a sample target to accumulate ions generated from a local ion source on a solid or liquid phase sample prior to applying a laser desorption pulse. The electric field is changed just prior to or during the desorption laser pulse to promote the desorption of charged species and improve the ionization efficiency of desorbed sample species. After a delay, the electric field may be further changed to optimize focusing and transmission of ions into a mass spectrometer or ion mobility analyzer. Charged species may also be added to the region of the laser desorbed sample plume to promote ion-molecule reactions between the added ions and desorbed neutral sample species, increasing desorbed sample ionization efficiency and / or creating desired product ion species. The cycling of electric field changes is repeated in a timed sequence with one or more desorption laser pulse occurring per electric field change cycle. Embodiments of the invention comprise atmospheric pressure, intermediate pressure and vacuum pressure laser desorption ionization source methods and devices for increasing the analytical flexibility and improving the sensitivity of mass spectrometric analysis.