Preparation enhancements and methods of use for maldi mass spectrometry

Abstract

Provided herein are compositions and methods useful for preparing and analyzing a sample on a substrate by matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS). In some embodiments, compositions provided herein comprise a substrate, matrix and nanoparticles, and sometimes comprise one or more additives and sometimes an analyte. Compositions provided herein sometimes comprise nanoparticles that include or are made up of silicon dioxide. Compositions provided herein sometimes comprise a substrate comprising a substantially planar surface and a plurality of sample containment structures.

What is claimed is: 
     
         1 . A matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) substrate comprising a substantially planar surface and a plurality of sample containment structures;
 each of which containment structures comprises one or more depressions disposed in the substrate, one or more projections disposed on the substrate, or one or more depressions disposed in the substrate and one or more projections disposed on the substrate; and   each of which containment structures is configured to isolate a sample comprising a MALDI MS matrix in a particular location of the substrate as a sample dries on the substrate, and is configured to contain the sample after the sample has dried.   
     
     
         2 . The mass spectrometry substrate of  claim 1 , wherein each of the containment structures comprises one or more edges or points. 
     
     
         3 . The mass spectrometry substrate of  claim 2 , wherein the one or more edges are formed between a surface of the containment structure and the substantially flat substrate surface. 
     
     
         4 . The mass spectrometry substrate of  claim 2 , wherein the one or more edges are formed between two surfaces of the containment structure. 
     
     
         5 . The mass spectrometry substrate of  claim 1 , wherein each of the containment structures comprises a substantially flat surface or a substantially curved surface, or a substantially flat surface and a substantially curved surface. 
     
     
         6 . The mass spectrometry substrate of  claim 1 , wherein each of the containment structures is chosen from wells, ridges and posts. 
     
     
         7 . The mass spectrometry substrate of  claim 6 , comprising wells. 
     
     
         8 . The mass spectrometry substrate of  claim 7 , wherein the profile of the wells comprises a rectangle, polygon, triangle, circle, oval or ellipse. 
     
     
         9 . The mass spectrometry substrate of  claim 7 , wherein the wells have a width at the substrate surface of about 2 millimeters or less and have a depth of about 100 micrometers or less. 
     
     
         10 . The mass spectrometry substrate of  claim 7 , wherein a wall of the wells comprise a substantially curved surface or a substantially flat surface, or a substantially curved surface and a substantially flat surface. 
     
     
         11 . The mass spectrometry substrate of  claim 7 , wherein the bottom of each of the wells comprises a substantially curved surface or a substantially flat surface, or a substantially curved surface and a substantially flat surface. 
     
     
         12 . The mass spectrometry substrate of  claim 6 , which comprises ridges or posts. 
     
     
         13 . The mass spectrometry substrate of  claim 12 , wherein the ridges are in a containment structure that comprises a well. 
     
     
         14 . The mass spectrometry substrate of  claim 13 , wherein each of the wells are raised wells. 
     
     
         15 . The mass spectrometry substrate of  claim 13 , wherein the wells have an internal width at the proximal opening of each well of about 2 millimeters or less and have a depth of about 100 micrometers or less. 
     
     
         16 . The mass spectrometry substrate of  claim 13 , wherein a wall of each of the wells comprises a substantially curved surface or a substantially flat surface, or a substantially curved surface and a substantially flat surface. 
     
     
         17 . The mass spectrometry substrate of  claim 13 , wherein the bottom of each of the wells comprises a substantially curved surface or a substantially flat surface, or a substantially curved surface and a substantially flat surface. 
     
     
         18 . The mass spectrometry substrate of  claim 1 , wherein the structures are disposed on the substrate in an array. 
     
     
         19 . The mass spectrometry substrate of  claim 18 , comprising about 24 structures, about 96 structures or about 384 structures. 
     
     
         20 . The mass spectrometry substrate of  claim 1 , wherein the substrate comprises one or more surfaces that are substantially hydrophobic. 
     
     
         21 . The mass spectrometry substrate of  claim 1 , wherein the containment structures comprise one or more surfaces that are substantially hydrophobic. 
     
     
         22 . The mass spectrometry substrate of  claim 20 , wherein the substrate comprises one or more surfaces that are relatively hydrophilic. 
     
     
         23 . The mass spectrometry substrate of  claim 20 , wherein the containment structures comprise one or more surfaces that are relatively hydrophilic. 
     
     
         24 . The mass spectrometry substrate of  claim 22 , wherein the one or more surfaces that are relatively hydrophilic comprise a photoresist. 
     
     
         25 . The mass spectrometry substrate of  claim 23 , wherein the one or more surfaces that are relatively hydrophilic comprise a photoresist.