Patent ID: 6943036

Claim:
A method of forming an addressable array of chemical moieties on a substrate, comprising: (a) providing a substrate having multiple feature locations and multiple test locations; (b) depositing a reagent drop set from a single dispenser onto each feature location so as to attach a corresponding moiety for each feature location, wherein said deposition of a reagent drop set is a cycle; (c) repeating step (b) at each feature location until the addressable array is formed; wherein for each feature location of said addressable array a multi-dispenser drop group is deposited thereon, wherein said multi-dispenser drop group is formed over two or more cycles of (b) and (c); and wherein said drops deposited in said two or more cycles are deposited from at least two or more different dispensers; the method additionally comprising: (d) depositing individual reagent drops of a previously formed multi-dispenser drop group from said different dispensers at respective, separate test locations on the substrate; wherein each of said separate test locations does not include a previously deposited drop; and (e) detecting said individual reagent drops at said respective test locations.