Abstract: A method of detecting arsenic comprising acidifying at least one sample comprising a known arsenic concentration, reducing arsenic in the sample having the known arsenic concentration to arsine, contacting the arsine in the sample having the known arsenic concentration with a reagent to produce a chemiluminescent emission, measuring the intensity of chemiluminescent emission produced by the sample having the known arsenic concentration, acidifying at least one sample comprising an unknown arsenic concentration, reducing arsenic in the sample having the unknown arsenic concentration to arsine, contacting the arsine in the sample having the unknown arsenic concentration with a photoagent to produce a chemiluminescent emission, measuring the intensity of chemiluminescence emission produced by the sample having the unknown arsenic concentration, and determining the arsenic content in the sample having an unknown arsenic concentration by comparing the intensity of chemiluminescent emission of the sample comprising

Abstract: The present invention provides a method of performing analyses and assays involving multiple interactions of reagent-containing fluid flows with liquid and solid target substances. The methods of the invention allow the simultaneous manipulation of different fluids on a small planar surface. The invention also provides a flow cell and method of use thereof for analyzing fluid-fluid and fluid-solid interactions in a substantially planar system. The flow cell contains at least one chamber and a plurality of inlets thereto allowing the introduction of a plurality of fluids in fluidic contact. The cell depth is the smallest dimension of the flow cell, and is of a magnitude, from about 50 to about 1000 microns such that any mixing of adjacent fluids in the chamber is substantially limited to mixing by passive diffusion.