Patent ID: 7247495

Claim:
Mass spectrometric method for analyzing a sample in a liquid solution for producing mass spectral information having an enhanced molecular ion for identifying and/or quantifying the chemical content of the sample, comprising the steps of: directing a flow of a solution containing sample compounds to be analyzed towards a supersonic nozzle; vaporizing the solution containing the sample compounds; expanding the vaporized sample from said supersonic nozzle into a vacuum system, forming a supersonic molecular beam; ionizing with electrons the vaporized sample compounds; mass analyzing the ions formed from said sample compounds; detecting said ions formed from said sample compounds after mass analysis; processing the data obtained from the resulting mass spectral information for identifying and/or quantifying the chemical content of said sample, and wherein the flow of said solution is a liquid flow; said sample compounds vaporization being aided by a prior solvent spray formation; said spray droplets are evaporated and the emerging sample particles are further vaporized to form vaporized sample molecules; the vaporization of said sprayed directed flow of a solution containing sample compounds is effected prior to its expansion from said supersonic nozzle; cooling said vaporized sample compounds through its expansion from said supersonic nozzle; forming a supersonic molecular beam of both, vibrationally cold sample compounds and solvent molecules; the ionization of said vibrationally cold sample compounds while contained in said supersonic molecular beam in a fly through electron ionization ion source; whereby to produce mass spectra with enhanced molecular ions; and said data obtained from the resulting mass spectral information includes enhanced molecular ions compared with the particle beam method for improved identifying and/or quantifying of the chemical content of said sample.