Method and apparatus for purifying and desalting biological samples

Abstract

The subject invention provides a sample processing technique for purifying a biological or chemical sample. The invention is particularly well-suited to prepare a sample for mass spectrometry. The process is to be performed in an article having at least one well, in which the surface of the well is at least partially hydrophobic and/or modified with bio-specific ligands. Targeted solutes, such as salts or small molecule contaminants, can be removed from a solution to allow for a purified solution of a desired type of solute, such as peptides and/or proteins.

1 . A process for purifying a biological or chemical sample, said process comprising:
 providing an article having a well with a surface which is at least partially modified with bio-specific ligands;   depositing a liquid sample in said well;   evaporating said liquid sample with a first class of solutes in said sample tightly binding to said surface, and a second class of solutes in said sample not tightly binding to said surface;   depositing a first buffer in said well, said first buffer disassociating said second class of solutes from said surface;   removing said first buffer and said disassociated second class of solutes from said well; and   depositing a second buffer in said well after removing said first buffer, said second buffer disassociating said first class of solutes from said surface.   
   
   
       2 . A process as in  claim 1 , wherein said article is a multi-well plate. 
   
   
       3 . A process as in  claim 1 , wherein said article is a column. 
   
   
       4 . A process as in  claim 1 , wherein said article is a pipette. 
   
   
       5 . A process as in  claim 1 , wherein said article includes a target support plate having spaced-apart top and bottom surfaces, at least one column extending between, and through, said top and bottom surfaces, and a target device releasably secured to said target support plate, said target device having at least one collection site, said column registering with said collection site, said column and said collection site collectively defining said well. 
   
   
       6 . A process as in  claim 5 , wherein said target device is releasably secured to said target support plate. 
   
   
       7 . A process as in  claim 5 , wherein at least the bottom surface of said target support plate is formed of an elastomeric material releasably adhered to said target device. 
   
   
       8 . A process as in  claim 7 , wherein said elastomeric material includes a silicon polymer. 
   
   
       9 . A process as in  claim 7 , wherein said elastomeric material includes poly(dimethyl)siloxane. 
   
   
       10 . A process as in  claim 7 , wherein said target support plate is wholly formed of said elastomeric material. 
   
   
       11 . A process as in  claim 5 , wherein said target device is a mass spectrometry plate. 
   
   
       12 . A process as in  claim 1 , wherein said liquid sample includes tryptic digest products. 
   
   
       13 . A process as in  claim 1 , wherein said first class of solutes includes peptides. 
   
   
       14 . A process as in  claim 1 , wherein said first class of solutes includes proteins. 
   
   
       15 . A process as in  claim 1 , wherein said second class of solutes includes salts. 
   
   
       16 . A process as in  claim 1 , wherein said second class of solutes includes small molecule contaminants. 
   
   
       17 . A process as in  claim 1 , wherein said first buffer includes water. 
   
   
       18 . A process as in  claim 1 , wherein said second buffer includes an organic solvent. 
   
   
       19 . A process as in  claim 1 , wherein said second buffer includes an energy absorbing matrix. 
   
   
       20 . A process as in  claim 1 , wherein said bio-specific ligands may be one or more selected from the group consisting of immobilized metal ion affinity chromatography (IMAC) matrices for phosphorylated peptides/proteins or poly(histidine) fused peptides/proteins, biotin affinity matrices for biotinylated peptide/proteins, and thiol-disulfide exchange chromatography matrices for glutathione S-transferase (GST) fused peptides/proteins.