Abstract: An automated cold vapor mercury assay system includes a sample inlet, a storage chamber of predetermined volume for storing a sample of material to be analyzed, a reaction chamber having first and second inlet ports and an outlet port, a reducing agent reservoir, a transport liquid reservoir, a distributor coupled to the sample storage chamber and movable between a first position connecting the storage chamber to the sample inlet and a second position connecting the storage chamber to the reaction chamber, analyzer apparatus coupled to the outlet port of the reaction chamber structure, and controller structure.

Abstract: Solvent composition gradients in high performance liquid chromatography (HPLC) are generated with a packed bed gradient generator. Natural dispersion occurs in flow through a bed of particles due to eddy and molecular diffusion. This dispersion changes a sharply defined front between two solvents into a desirable error function type gradient profile at the interface between the solvents. The packed-bed gradient generator is a cylindrical tube filled with chemically inert glass beads. Other axial column contours such as a double taper column or bell-shaped entrance and exit regions can be used to tailor the gradient profile. The static packed-bed gradient generator can be placed either on the low pressure inlet side of the high pressure pump, or the high pressure outlet side of the pump. While low pressure operation may provide added convenience, high pressure operation provides additional pulse dampening ability.