Device for delivery of multiple liquid sample streams to a mass spectrometer

Abstract

An electrospray apparatus employing multiple electrospray needles mounted on a rotatable plate sequentially delivers multiple sample streams to a mass spectrometer for analysis. The electrospray device includes an electrospray chamber, a rotatable needle supporting plate, a plurality of electrospray needles mounted on the plate, and a charger for applying a charge to droplets delivered to the electrospray chamber by the needles. The rotatable electrospray apparatus provides fast repetitive screening of simultaneously operating chromatography columns with a single mass spectrometer.

What is claimed is:  
     
         1 . An electrospray device for a mass spectrometer comprising: 
 an electrospray chamber;    a rotatable needle support;    a plurality of electrospray needles mounted on the rotatable needle support, the electrospray needles connectable to a plurality of sample streams for delivery of droplets of one of the sample streams at a time to a mass spectrometer orifice of the electrospray chamber; and    a charger for applying a charge to the droplets of the sample stream in the electrospray chamber and causing ions to be focused into a beam passing through the orifice into the mass spectrometer.    
     
     
         2 . The electrospray device according to  claim 1 , wherein the rotatable needle support is a rotatable disk having the plurality of electrospray needles mounted in a substantially circular parallel arrangement on the disk.  
     
     
         3 . The electrospray device according to  claim 1 , wherein the rotatable needle support is a rotatable disk having the plurality of electrospray needles mounted in a radial arrangement on the disk.  
     
     
         4 . The electrospray device according to  claim 1 , wherein the plurality of electrospray needles are coaxial needles having an inner lumen for delivery of the sample stream and an outer lumen for delivery of a nebulizer gas.  
     
     
         5 . The electrospray device according to  claim 1 , wherein the charger comprises a charged sampling plate positioned within the electrospray chamber substantially surrounding the mass spectrometer orifice and an electrode positioned on an opposite side of the electrospray needle from the charged sampling plate.  
     
     
         6 . The electrospray device according to  claim 1 , wherein the charger comprises an electrical contact for electrically charging the electrospray needles by connection to a voltage source.  
     
     
         7 . The electrospray device according to  claim 1 , wherein the electrospray chamber includes a chamber wall having slots for allowing the electrospray needles to pass into and out of the electrospray chamber.  
     
     
         8 . The electrospray device according to  claim 1 , further comprising a plurality of chromatography columns mounted on the rotatable needle support, wherein each of the chromatography columns is in fluid connection to one of the electrospray needles for delivery of the sample streams exiting the chromatography columns to the mass spectrometer.  
     
     
         9 . The electrospray device according to  claim 1 , further comprising a motor for rotation of the rotatable needle support and a controller for controlling the rotation of the needle support to achieve a consistent dwell time for each of the electrospray needles.  
     
     
         10 . The electrospray device according to  claim 9 , wherein the controller rotates the needle support in a first direction to analyze the sample streams from approximately one half to the electrospray needles and rotates the needle support in a second direction to analyze the sample streams from a remaining approximately one-half of the electrospray needles.  
     
     
         11 . A method of delivering a plurality of sample streams to a mass spectrometer for sequential analysis, the method comprising: 
 providing a plurality of sample streams to a plurality of electrospray needles mounted on a rotating plate;    continuously spraying the sample streams with the electrospray needles; and    sequentially positioning an outlet of each of the electrospray needles at delivery position for a predetermined dwell time by rotating and stopping the plate to deliver the sample streams to the mass spectrometer.    
     
     
         12 . The method according to  claim 11 , wherein the predetermined dwell time is about 0.5 to 10 seconds.  
     
     
         13 . The method according to  claim 11 , wherein the plate is rotated in a first direction to sequentially deliver a plurality is sample streams to the mass spectrometer and the plate is then rotated in a second direction.  
     
     
         14 . The method according to  claim 11 , wherein the electrospray needles which are not positioned at the delivery position deliver the sample streams to a collection tray.