Abstract: Water-stable phenol-amine complexes of limited water solubility for use in a thermal-sensitive paper coating containing a chromogenic compound.The complexes contain phenolic hydroxy groups and amine groups in an essentially 2:1 ratio, the amines being low boiling amines. The phenols are of the class capable of forming amine complexes having a ratio of two hydroxyl groups for each amine group. The resulting coating compositions effectively resist premature color formation during formulation, and the coated papers produced exhibit enhanced stability.

Abstract: A highly stable, double-junction, modular reference electrode for assay of low-level halide concentrations, sulfides, perchlorates, silver, mercury, and other heavy metals, and including upper and lower axially in-line, readily accessible and conveniently fillable compartments for retaining electrically conductive compositions, an intercoupling removable plug constituting fluid-tight means bridging axially between the compartments and carrying a conduit providing a fluid permeable electrically and ionically conductive path between the compartments, an external cable lead projecting through a sealing cap closing the upper compartment for establishing electrical contact with a conductive medium contained in the upper compartment, a removable sealing plug at a lower open end of the lower compartment, and a conduit extending axially through said plug and providing a flow-restrictive fluid permeable path between the lower compartment and a test system external of the electrode.