| CPC G01N 30/30 (2013.01) [G01N 30/466 (2013.01); G01N 30/606 (2013.01); G01N 2030/025 (2013.01)] | 20 Claims | 

| 
               1. A system for chromatography, comprising: 
            a first chromatography column formed in a substrate; 
                a second chromatography column formed in the substrate; 
                a port formed in the substrate between the first chromatography column and the second chromatography column, wherein the first chromatography column terminates in the port and the port serves as an inlet to the second chromatography column; and 
                a flow control element coupled to the port and configured to open and close the port, wherein when the port is open the first chromatography column is in fluidic communication with the second chromatography column, and when the port is closed the first chromatography column and the second chromatography column are not in fluidic communication. 
               |