Mass spectrometric immunoassay

Abstract

Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

1 . A method of analyzing a sample comprising the acts of: 
 a. placing the sample in contact with an immobilized amino acid chain that has affinity to bind with a substance;    b. washing away at least a portion of the sample;    c. releasing at least a portion of any of the substance that bound to the amino acid chain;    d. performing mass spectrometry on a mixture that includes laser desorption/ionization agent and any of the released substance; and    e. analyzing results of the mass spectrometry to detect any of the substance present in the sample.    
     
     
         2 . The method according to  claim 1  where the sample is biological.  
     
     
         3 . The method according to  claim 1  where the sample is heterogeneous.  
     
     
         4 . The method according to  claim 1  where the mixture of act (d) includes at least one internal reference substance.  
     
     
         5 . The method according to  claim 4  where the amount of substance present is quantified with the internal reference substance.  
     
     
         6 . The method according to  claim 1  where the presence or absence of one or more substances correlates to a biological process or disease.  
     
     
         7 . The method according to  claim 1  where the amino acid chain comprises a peptide.  
     
     
         8 . The method according to  claim 1  where the amino acid chain comprises an antibody.  
     
     
         9 . The method according to  claim 1  where the amino acid chain comprises an antigen.  
     
     
         10 . The method according to  claim 1  where the amino acid chain comprises a protein.  
     
     
         11 . The method according to  claim 1  further comprising the act of identifying any substance present.  
     
     
         12 . The method according to  claim 1  further comprising the act of quantifying the amount any substance present.  
     
     
         13 . The method according to  claim 1  where the sample comprises human blood.  
     
     
         14 . The method according to  claim 1  where the sample comprises human blood serum.  
     
     
         15 . The method according to  claim 1  where the substance comprises an antibody.  
     
     
         16 . The method according to  claim 1  where the substance comprises a molecule with an antigenic site.  
     
     
         17 . The method according to  claim 1  where the substance comprises a biomarker.  
     
     
         18 . The method according to  claim 1  where the amino acid chain is immobilized onto a substrate selected from the group consisting of agarose beads, nylon, a metal, glass, silicon, and organic membrane.  
     
     
         19 . The method according to  claim 18  where the substrate is contained within a micropipette tip.  
     
     
         20 . The method according to  claim 1  where the act of releasing at least a portion of any substance of interest is accomplished using a member of the group consisting of buffer solution, heat, electric potential, and sound waves.  
     
     
         21 . The method according to  claim 1  where act (c) is accomplished using at least a laser desorption/ionization agent.  
     
     
         22 . The method according to  claim 1  where the act (a) occurs within a micropipette tip.  
     
     
         23 . A method of analyzing a sample comprising the acts of: 
 a. placing the sample in contact with an immobilized amino acid chain that has affinity to bind with a substance;    b. releasing at least a portion of any of the substance that bound to the amino acid chain; and    c. performing mass spectrometry on a mixture that includes laser desorption/ionization agent and any of the released substance;    
     
     
         24 . A method that determines whether a heterogeneous, biological sample contains an analyte comprising the acts of: 
 a. placing the heterogeneous, biological sample in contact with an immobilized antibody that has an affinity to bind with the analyte;    b. washing away at least a portion of the heterogeneous, biological sample;    c. releasing at least a portion of any analyte that bound to the antibody;    d. performing mass spectrometry on a mixture that includes a laser desorption/ionization agent and any released analyte; and    e. analyzing the results of the mass spectrometry to detect any analyte present in the sample.