System for optimizing alignment of laser beam with selected points on samples in maldi mass spectrometer

Abstract

A mass spectrometry apparatus uses image processing of output signals of a camera in a mass spectrometer to provide feedback for directing the laser. The present invention provides for the determination of where samples have actually been deposited on a plate, and for the selection of different points for each sample, based on its structure, at which to aim a laser, during the cycle period of the mass spectrometer. Such feedback information increases the likelihood that the laser impinges samples and provides useful data.

1 . A mass spectrometry apparatus comprising:
 a laser for emitting a laser beam;   a controller for directing said laser beam toward a plurality of samples on a sample plate for mass spectrometry analysis;   an image generating device for generating at least one image of at least part of said sample plate;   a computer configured to receive said image from said image generating device;   a light source for illuminating the imaged portion of the sample plate, the light source having a controllably adjustable angle of incidence with the sample plate;   said computer configured to process said image to determine features of said samples and to generate control signals for use by said controller to direct the manner in which said laser beam impinges said sample plate, said computer being operable to identify positions of said features of said samples relative to a reference framework and provide position data relating to said positions in said control signals;   wherein said samples are characterized by crystal structures, said computer being operable to identify points on said features at which to direct said laser, said points varying among said samples and said features depending on their respective structures, said image processing device providing data relating to said points in said control signals.   
   
   
       2 . A computer implemented method for processing images of samples deposited on a sample plate positioned within a mass spectrometer, comprising the steps of:
 generating an image of at least a portion of said sample plate from a camera having a field of view comprising at least part of said sample plate within the mass spectrometer;   obtaining an output signal generated via the camera, wherein the output signal from the camera is provided to the computer;   processing the image by the computer to identify features of the samples on said sample plate in said image;   generating by the computer a representation of the image that can be compared to a library of previously analyzed crystal structures;   extracting location data obtained from library images that correspond to the acquired image representation;   providing by the computer said location data to a controller to aim said control signals that correspond to said locations; and   wherein said position data is used by said controller to aim said laser at said locations for laser impingement.   
   
   
       3 . The method of  claim 2 , wherein location data is obtained from said library data by identifying an image in said library that is similar to the current sample plate image, and wherein location data corresponding to laser impingement positions have also been recorded and stored in said library, and said location data stored in said library are provided to said controller to aim said laser at said locations for laser impingement. 
   
   
       4 . The method of  claim 2 , wherein location data is obtained from said library data by identifying an image in said library that is similar to the current sample plate image, and wherein location data corresponding to laser impingement positions that generate the most desirable mass spectrometer data have also been recorded and stored in said library, and said location data stored in said library are provided to said controller to aim said laser at said locations for laser impingement. 
   
   
       5 . The method of  claim 2 , wherein the image of the sample being processed and the location data of the sample points which generate the most desirable mass spectrometry data are stored into said library.