Method for detecting and quantifying a target analyte in a sample

Abstract

The invention relates to a method for identifying and quantifying by mass spectrometry at least one target analyte in a sample, comprising the following steps: a) depositing the sample to be analyzed on a support; b) analyzing the sample by mass spectrometry, so as to obtain the mass spectrum of the target analyte in said sample; c) weighting a signal associated with the mass spectrum of the target analyte in said sample by a extinction coefficient (TEC) specific to the target analyte and to the sample; and d) using the weighted signal of the target analyte to determine the quantity of target analyte in the sample.

We claim: 
     
         1 . A method for detecting and quantifying by mass spectrometry imaging at least one target analyte in a sample, comprising the following steps:
 a) depositing the sample containing at least one target analyte to be analyzed on a support for mass spectrometry imaging and depositing a known concentration of isotopically labeled target analyte, as an internal standard, on said sample;   b) analyzing the sample by a mass spectrometry imaging technique so as to obtain a mass spectrum signal of said at least one target analyte and a mass spectrum signal of the isotopically labeled target analyte in said sample;   c) weighting the signal associated with the mass spectrum of said at least one target analyte in said sample by an extinction coefficient specific to each of said at least one target analyte and to the sample, wherein said extinction coefficient corresponds to a ratio of the signal of the at least one target analyte to the signal of the isotopically labeled target analyte, or the inverse; and   d) using each weighted signal of each of said at least one target analyte to determine the quantity and distribution of each of said at least one target analyte in the sample.   
     
     
         2 . The method according to  claim 1 , wherein said at least one target analyte is a protein, a peptide, a lipid, a metabolite or a small molecule. 
     
     
         3 . The method according to  claim 1 , wherein the sample is an organic sample or an inorganic sample. 
     
     
         4 . The method according to  claim 1 , wherein the sample is a biological sample. 
     
     
         5 . The method according to  claim 1 , wherein said at least one target analyte is a protein and an enzymatic and/or chemical pretreatment of said protein is performed prior to detection step b), and wherein detection and quantification are carried out for at least one of the peptides resulting from said pretreatment. 
     
     
         6 . The method according to  claim 1 , wherein the sample is treated with at least one solvent and/or at least one detergent prior to analysis step b). 
     
     
         7 . The method according to  claim 1 , wherein the mass spectrum signal corresponds to the intensity of the peak, the area of the peak or the signal-to-noise ratio of the mass spectrum of at least one target analyte. 
     
     
         8 . The method according to  claim 1 , wherein the signal intensity of the target analyte is weighted directly on the analyzed sample so as to simultaneously visualize the distribution and the concentration of the target analyte in said sample. 
     
     
         9 . The method according to  claim 1 , wherein the isotopically labeled target analyte is labeled with deuterium atoms. 
     
     
         10 . The method according to  claim 1 , wherein a known concentration of the isotopically labeled target analyte is mixed with a matrix before spreading the resulting mixture over the tissue sample. 
     
     
         11 . The method according to  claim 1 , wherein the isotopically labeled target analyte is solubilized in a solvent before deposition on the sample and the support, and an evaporation of the solvent is performed before the mass spectrometry imaging analysis. 
     
     
         12 . The method according to  claim 1 , wherein a matrix is deposited on the sample before analysis step b) and wherein before analysis step b) the homogeneity of the matrix deposition on the sample is evaluated in relation to a deposition of a reference matrix. 
     
     
         13 . The method according to  claim 1 , wherein at least two different target analytes in said sample are detected and quantified simultaneously. 
     
     
         14 . The method according to  claim 1 , wherein the sample is a section of whole animal and wherein the target analyte is detected and quantified by mass spectrometry imaging directly on said section so as to simultaneously compare the distribution of said target analyte in various tissues of the animal. 
     
     
         15 . A computer-readable data medium comprising computer-executable instructions suited to enable a computer system to execute step c) of the method according to  claim 1 . 
     
     
         16 . The method according to  claim 1 , wherein the target analyte is ionizable.