Improved Methods and Devices for Concentration and Fractionation of Analytes for Chemical Analysis including Matrix-Assisted Laser Desorption/Ionization (MALDI) Mass Spectrometry (MS)
A device for pre-concentration and purification of analytes from biological samples, such as human serum, to be analyzed by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI MS) and methods of use thereof are provided.
1 . A device for electrophoretically separating, concentrating, and capturing an analyte in a sample comprising:
a sample well for retaining a fluid sample in an electrolyte;
a separation layer providing a path for diffusive ionic, and fluidic communication with the well; and
a capture layer providing a path for diffusive ionic, and fluidic communication with the separation layer.
2 . The device of claim 1 wherein the sample well comprises a top opening, side walls, and a bottom opening, and wherein the sample well is progressively reduced in dimension from the top opening to the bottom opening.
3 . The device of claim 1 wherein the sample well has a total interior volume of up to about 400 μL.
4 . The device of claim 1 comprising a plurality of sample wells disposed as an array of sample wells.
5 . The device of claim 1 wherein the separation layer is comprised of a gel.
6 . The device of claim 5 wherein the gel is a polyacrylamide gel.
7 . The device of claim 1 wherein the separation layer is disposed within an aperture disposed in a cartridge gel plate.
8 . The device of claim 1 wherein an array of substantially identical separation layers are disposed within an array of substantially identical apertures disposed in a cartridge gel plate.
9 . The device of claim 8 wherein the cartridge gel plate is manufactured of an electrically insulating thermoplastic polymer.
10 . The device of claim 8 wherein the separation layers are covalently bound to the cartridge gel plate at the apertures of the cartridge gel plate.
11 . The device of claim 1 wherein the capture layer is a porous material.
12 . The device of claim 1 wherein the capture layer is a hydrophobic porous polymer, a hydrophilic porous polymer, or a mixture of hydrophilic and hydrophobic polymers.
13 . The device of claim 1 wherein the capture layer is a porous poly(vinylidene difluoride) material.
14 . The device of claim 1 wherein the capture layer is disposed within an aperture disposed in a cartridge capture slide.
15 . The device of claim 1 wherein an array of substantially identical capture layers are disposed within an array of substantially identical apertures disposed in a cartridge capture slide.
16 . The device of claim 15 wherein the cartridge capture slide has low electrical conductivity so as to provide for dissipation of static charge.
17 . The device of claim 15 wherein the cartridge capture slide has a volume resistivity of between about 10 4 and about 10 8 ohm-cm.
18 . The device of claim 15 wherein the cartridge capture slide has a flatness, or is capable of being flattened when inserted into a MALDI mass spectrometer, to +/−50 microns.
19 . The device of claim 15 wherein the cartridge capture slide is about 5.3 mm long, about 3.5 mm wide, and about 1 mm thick.
20 . The device of claim 15 wherein the substantially identical apertures in the capture slide are substantially circular and are about 0.5-1 mm in diameter.
21 . The device of claim 15 wherein two or more cartridge capture slides are stacked in series such that the capture layers in one cartridge capture slide are aligned with corresponding capture layers in an adjacent cartridge capture slide.
22 . The device of claim 21 wherein the capture layers in one cartridge capture slide are in fluid and electrical communication with corresponding capture layers in an adjacent capture slide.
23 . A device for capturing a sample analyte for analysis in a mass spectrometer comprising:
a cartridge capture slide comprising a plurality of apertures disposed therein;
a plurality of capture layers disposed in the plurality of apertures.
24 . The device of claim 23 wherein the capture layers manufactured from a porous material.
25 . The device of claim 24 wherein the porous material is a hydrophobic porous polymer, a hydrophilic porous polymer, or a mixture of hydrophilic and hydrophobic polymers.
26 . The device of claim 23 wherein the capture layers are porous poly(vinylidene difluoride).
27 . The device of claim 23 wherein the plurality of apertures containing the plurality of capture layers are arranged as an array.
28 . The device of claim 27 wherein the array comprises 96 apertures.
29 . The device of claim 23 wherein the cartridge capture slide has low electrical conductivity so as to provide for dissipation of static charge.
30 . The device of claim 23 wherein the cartridge capture slide has a volume resistivity of between about 10 4 and about 10 8 ohm-cm.
31 . The device of claim 23 wherein the cartridge capture slide has a flatness, or is capable of being flattened when inserted into a MALDI mass spectrometer, to +/−50 microns.
32 . The device of claim 23 wherein the cartridge capture slide is about 5.3 mm long, about 3.5 mm wide, and about 1 mm thick.
33 . The device of claim 23 wherein the cartridge capture slide wherein the plurality of apertures in the capture slide are substantially circular and are about 0.5-1 mm in diameter.
34 . A method for identifying an analyte by mass spectrometric analysis comprising:
providing the device of claim 1;
placing a sample fluid containing an analyte in the sample well;
applying an electrical current to the sample fluid to effect electrical transport of the analyte through the separation layer and onto the capture layer; and
identifying the mass of analytes on the capture layer in a mass spectrometer.
35 . A cartridge capture slide adaptable for use in a mass spectrometer comprising:
an array of apertures disposed in the cartridge capture slide; and
an array of capture layers disposed in the array of apertures,
wherein the cartridge capture slide is incorporated within a device comprising an array of sample wells and a cartridge gel plate, and wherein the cartridge gel plate comprises an array of apertures in which are disposed an array of separation layers.
36 . The cartridge capture slide according to claim 35 having a volume resistivity of between about 10 4 and about 10 8 ohm-cm.
37 . The cartridge capture slide according to claim 35 having a flatness, or capable of being flattened when inserted into a MALDI mass spectrometer, of +/−50 microns.
38 . The cartridge capture slide according to claim 35 having length of about 5.3 mm, width of about 3.5 mm, and thickness of about 1 mm.
39 . The cartridge capture slide according to claim 35 wherein the plurality of apertures are substantially circular and are about 0.5-1 mm in diameter.