I have a rice proteomic paper,what do these mean: "2-D PAGE" , "HPLC-Tandem...

[eTeRnItY]

...Mass Spectrometry for gel Spots"? In this proteomic paper ,the material and methods part divided into 3 parts:
-Tissue Preparation
-2-D PAGE
-HPLC-Tandem Mass Spectrometry for Gel Spots
I wanna know about "2-D PAGE" , "HPLC-Tandem Mass Spectrometry for Gel Spots".
TQ

[danfive]

2-D page--2 dimensional electrophoresis, literally proteins are separated along two dimensions isoelectric point and molecular size (just like x and y axis in algebra, they have two coordinates)

HPLC-MS-MS---high performance liquid chromatography followed by tandem mass spectrometry---the proteins from 2D gels are stained and look like spots, they are carefully cut up, separately, then liquified--run through HPLC--which separates the components in the protein spot--and fed into a mass spectrometer---which ionizes the proteins--measures the size and charge---separates them---picks the interesting peptides (small proteins)--runs them through a collider---breaks them apart and again measures the size and charge of individual amino acids---thus deciphering the exact sequence of the proteins of interest and giving a very accurate identification of the protein in the original "spot."