Abstract: 1,5-Bis(2-hydroxyphenyl)-3-cyanoformazans substituted in at least one of the 3-, 4- and 5-positions of either phenyl moiety are useful for the determination of magnesium ions. The cyanoformazan substituents are chosen such that their cumulative Hammett-sigma value is greater than about 0.23. These cyanoformazans are useful in analytical compositions and methods for either wet or dry assay of magnesium ions.

Abstract: Certain phenalenimine fluorescent compounds represented by the structure ##STR1## wherein R' and R" are independently hydrogen, alkyl, cycloalkyl, aryl or a heterocycle, or R' comprises the carbon and heteroatoms which form a fused ring with the compound nucleus, are useful in biomedical and analytical determinations. These compounds can be used for staining cells, as well as for the determination of various analytes found in human or animal biological fluids. Such determinations can be carried out in solution or by using dry analytical elements. The fluorescent compounds can be reacted with quinone nuclei to form reducible compounds which are also useful in analytical methods. In addition, the compounds can be incorporated into what are known as "loadable" latex particles to form detectable labels and biological reagents.

Abstract: Certain phenalenimine fluorescent compounds represented by the structure ##STR1## wherein R' and R" are independently hydrogen, alkyl, cycloalkyl, aryl or a heterocycle, or R' comprises the carbon and heteroatoms which forms a fused ring with the compound nucleus, are useful in biomedical and analytical determinations. These compounds can be used for staining cells, as well as for the determination of various analytes found in human or animal biological fluids. Such determination can be carried out in solution or by using dry analytical elements. The fluorescent compounds can be reacted with quinone nuclei to form reducible compounds which are also useful in analytical methods. In addition, the compounds can be incorporated into what are known as "loadable" latex particles to form detectable labels and biological reagents.

Abstract: Hydrolyzable substrates comprise blocked dye moieties which, when cleaved from the substrate during hydrolysis, provide fluorescent dyes having maximum absorptions above about 530 nm and maximum emissions at least about 580 nm at physiological pH. These substrates can be used in analytical determinations of hydrolytic substances including hydrolytic enzymes or biological cells containing such enzymes.

Abstract: Certain phenalenone and benzphenalenone fluorescent compounds are useful in biomedical studies and analytical determinations. These compounds are particularly useful in assays for living organisms, e.g. microorganisms, carried out at a pH of 9 or less. For these determinations, the compounds can be attached to reducible compounds which will subsequently release the fluorescent moiety upon reduction. In the presence of an electron transfer agent, the reducible compounds are easily reduced by a microorganism.

Abstract: Novel chromogenic derivatives of 1,2-bis-(o-aminoaryloxy)ethane-N,N,N',N'-tetraacetic acid are useful for the determination of calcium ions in both solution and dry assays. These compounds comprise a dye moiety which is directly conjugated to the acetic acid substituted-nitrogen atom and which enables the compounds to exhibit maximum absorbance at a wavelength generally greater than 400 nm before complexation. When the compounds are complexed with calcium ions, the absorbance shifts to a shorter wavelength.

Abstract: New substrates for .gamma.-glutamyltransferase (.gamma.-GT) are disclosed. These subtrates are useful in the colorimetric determination of .gamma.-GT since the cleavage of the .gamma.-glutamyl group produces a detectable species--an aminostyrylquinolinium dye. The substrates have the formula: ##STR1## wherein: R and R.sub.1 are independently selected from hydrogen, alkyl and alkoxy andQ is ##STR2## wherein: R.sub.2 is alkyl having from 1 to 4 carbon atoms;R.sub.3 and R.sub.4 are independently selected from hydrogen, alkyl, alkoxy, nitro, cyano and halogen; andX.sup..crclbar. is an anion.

Abstract: A particular class of triarylmethane leuco dyes are useful in analytical compositions, elements and methods. These leuco dyes are triarylmethane compounds having an aromatic heterocyclic moiety attached to the central methane carbon and which, upon interaction with hydrogen peroxide, provide dyes having a maximum absorption at a wavelength equal to or greater than about 600 nm. Particularly useful leuco dyes have the structure: ##STR1## wherein R is a 5- to 15-membered aromatic heterocyclic moiety; and R' and R" are independently open chain or cyclic amines. These compounds are useful for providing detectable dyes in compositions and elements useful for detection of hydrogen peroxide or other analytes which react to produce hydrogen peroxide in aqueous liquids, e.g. biological fluids.

Abstract: A method for the determination of the amount of lipase in a sample comprises the steps of:(a) contacting the sample with a reagent composition comprising:(i) a lipase substrate which is a glycerol triester oil having in one of its two .alpha.-ester positions a long chain alkyl group having at least 8 carbon atoms and, in its two remaining ester positions, short chain alkyl groups such that, if the long chain alkyl group is hydrolyzed, the resulting diester is water soluble; and(ii) an esterase enzyme capable of catalyzing the hydrolysis of a water soluble glycerol diester to glycerol; and(b) detecting the rate at which glycerol is formed.The compositions of the present invention include the substrate and enzyme as defined. The element of the invention comprises a support having thereon the described composition. The invention is useful for determining lipase in samples which contain endogenous glycerol, such as blood serum and other body fluids.

Abstract: Diazonium salts which are useful in an assay for bilirubin are disclosed. The novel salts have the structural formula: ##STR1## wherein X.sup.- is a stabilizing anion, Y is CO-- or SO.sub.2 --; and R.sup.1 and R.sup.2 are independently selected from hydrogen, alkyl, aryl, carboxyalkyl and hydroxyalkyl providing R.sup.1 and R.sup.2 are not both hydrogen; R.sup.3 and R.sup.4 are independently selected from groups such that the sum of the Hammett sigma values for R.sup.3 and R.sup.4 does not exceed +0.4 or R.sup.3 and R.sup.4 represent the carbon atoms necessary to complete a fused carbocyclic ring structure. Reagent compositions, analytical elements and methods which use the described diazonium salt are also disclosed.