Method for sequencing reaction cleanup by constant pressure differential ultrafiltration

A method for reducing the level of contaminants in a sequencing reaction, comprising the steps of,

• providing a quantity of sequencing reaction product having a concentration of contaminants;
• transferring said sequencing reaction product to a plurality of wells of a multiwell plate, each said well including an ultrafiltration membrane;
• applying a first constant pressure differential to said sequencing reaction product in each said well at a force capable of causing said contaminants to pass through said ultrafiltration membrane while retaining said sequencing reaction product on said membrane as retentate;
• and
• recovering said retentate substantially free of said contaminants from said membrane.