Sample support plates for MALDI mass spectrometry

Abstract

The invention refers to sample support plates for the mass spectrometric analysis of large molecules using matrix-assisted laser desorption ionization (MALDI). The invention consists of making the surface of the sample support plate extremely hydrophobic, whereby a favorable structure of MALDI matrix crystals for effective ionization is generated when drying the sample droplets to sample spots. Using tiny, hydrophilic anchor areas for the sample droplets in this hydrophobic environment, the pipetting process is made much easier and the sample spots can be precisely located on the sample support plates. As the sample droplets are pipetted on, they are drawn to the hydrophilic anchors even if they are applied slightly imprecisely and they form, after drying, a precisely located, monolithic crystal conglomerate, which possesses favorable characteristics for the MALDI process.

1 . A sample support plate for supporting a sample during mass spectrometric analysis using matrix-assisted laser desorption (MALDI), wherein the sample consists of droplets of sample solution of a predetermined size which are subsequently dried, the sample support plate comprising a substantially flat surface having a relatively high electrical conductivity and a plurality of anchor sites each of which is significantly more hydrophilic than a hydrophobic area immediately surrounding it such that the droplets are retained at the anchor sites.  
     
     
         2 . A sample support plate according to  claim 1 , wherein the hydrophilic anchor areas have a diameter which is between one half and one tenth of the diameter of said predetermined sample solution droplet size.  
     
     
         3 . A sample support plate according to  claim 1 , wherein the hydrophilic anchor areas form an array that corresponds to the basic well array of a microtiter plate with 9 millimeter distances or a finer array resulting from division of this distance by integer numbers.  
     
     
         4 . A sample support plate according to  claim 1 , wherein the sample support plate comprises a microtiter plate.  
     
     
         5 . A sample support plate according to  claim 1 , wherein the plate comprises a hydrophobic base material.