Electrospray-assisted laser desorption ionization device, mass spectrometer, and method for mass spectrometry

A mass spectrometer, comprising:

• a receiving unit disposed to admit therein ionized analytes that are derived from a sample, and that are to be analyzed by the mass spectrometer;
• and
• an electrospray-assisted laser desorption ionization device including:
• an electrospray unit including a reservoir for accommodating a liquid electrospray medium, and a nozzle which is disposed downstream of said reservoir, and which is configured to sequentially form liquid drops of said electrospray medium thereat, said nozzle being spaced apart from said receiving unit in a longitudinal direction so as to define a traveling path;
• a voltage supplying member disposed to establish between said nozzle and said receiving unit a potential difference which is of an intensity such that the liquid drops are laden with a plurality of charges, and such that the liquid drops are forced to leave said nozzle as multiple-charged ones for heading toward said receiving unit along the traveling path;
• and
• a laser desorption unit adapted to irradiate the sample such that, upon irradiation, at least one of the analytes contained in the sample is desorbed to fly along a flying path which intersects the traveling path so as to enable said at least one of the analytes to be occluded in the multiple-charged liquid drops, and such that as a result of dwindling in size of the multiple-charged liquid drops when approaching said receiving unit along the traveling path, charges of the liquid drops will pass on to said at least one of the analytes occluded therein to form a corresponding one of the ionized analytes.

A method for mass spectrometry, comprising the steps of:

• placing a sample containing a plurality of analytes on a sample stage;
• providing an electrospray unit that includes a reservoir for accommodating a liquid electrospray medium, and a nozzle disposed downstream of the reservoir and configured to sequentially form liquid drops of the electrospray medium thereat;
• providing a mass analyzer that is spaced apart from the nozzle of the electrospray unit in a longitudinal direction so as to define a traveling path for receiving and analyzing ionized analytes derived from the sample;
• providing a detector for detecting signals generated as a result of analyzing the ionized analytes by the mass analyzer, and for generating amass spectrum based on the signals;
• establishing a potential difference between the nozzle of the electrospray unit and the mass analyzer, the potential difference being of an intensity such that the liquid drops are laden with a plurality of charges, and such that the liquid drops are forced to leave the nozzle as multiple-charged ones for heading toward the receiving unit along the traveling path;
• irradiating the sample with a laser beam such that, upon irradiation, at least one of the analytes contained in the sample is desorbed to fly along a flying path which intersects the traveling path so as to enable said at least one of the analytes to be occluded in the multiple-charged liquid drops, and such that as a result of dwindling in size of the multiple-charged liquid drops when approaching the receiving unit along the traveling path, charges of the liquid drops will pass on to said at least one of the analytes occluded therein to form a corresponding one of the ionized analytes.