Abstract: A method and multilayer analytical element for the determination of catechol and catechol generating substances such as salicylate is described. A series of enzymatic conversions involving tyrosinase is used to convert catechol to o-quinone and the latter to convert a leuco dye to a colored dye.

Abstract: An immunoassay element comprising at least one layer containing a leuco dye coating composition comprising:______________________________________ Dry Weight Component Ratio (Range) ______________________________________ a) Triarylimidazole leuco dye 55-80 b) Antioxidant 7-40 c) Poly[poly(ethylene oxide)-block- 6-20 poly(propylene oxide)] nonionic block copolymer d) Alkylaryloxypoly(alkylene oxide) 1-16 nonionic surfactant ______________________________________

Abstract: An incubator and its cover are provided for an analyzer, and especially a mechanism for raising and lowering the cover. Such a mechanism includes a connector between the cover and incubator that allows the cover to be raised to a superimposed position, but not rotated. A pivot pin is mounted directly between the connector and the cover so that the cover can be pivoted relative to the connector to complete exposure of the incubator for access. A latch is provided on the connector for automatically latching the cover in the raised position as soon as the cover is pivoted in the plane at least part way from the superimposed position.

Abstract: A buffered composition containing a nonionic or anionic surfactant, and a certain amount of a hydroxamic acid (or salt thereof) or an acyl hydrazine can be used as a wash composition in specific binding assays. Such assays include the use of a peroxidase labeled specific binding reactant to form a detectable peroxidase-labeled specific binding complex. The buffered composition and labeled reactant can be supplied in a diagnostic test kit. The hydroxamic acid or acyl hydrazine can be represented by the structure(I):R--CO--NH--R'wherein R is aryl or 6 to 10 carbon atoms in the aromatic nucleus, alkyl of 1 to 7 carbon atoms, cycloalkyl of 5 to 10 carbon atoms in the ring, or heterocyclyl of 5 to 10 atoms in the ring, at least one of which is an oxygen, nitrogen or sulfur atom, and R' is hydroxy or amino.

Abstract: An incubator comprises a rotor ring with two sets of apertures displaced along an arc of rotation, holding a cuvette in them. The apertures of one set are connected to an aperture of the other by a slot sized to allow passage of an elevator lead screw, but not a cuvette, between the apertures, the cuvette being raised on the top of the elevator during such passage. The elevator can also be used to move the cuvette into contact with a luminometer.