The present invention relates to azo dyes of formula (1), wherein D is a radical of formula (2) or (3), R.sub.1 and R.sub.2 independently denote hydrogen; C.sub.6-C.sub.10aryl which is unsubstituted or substituted by cyano, carboxy, hydroxy, halogen, C.sub.1-C.sub.6alkyl, or C.sub.1-C.sub.6alkoxy; C.sub.1-C.sub.12alkyl which may be interrupted one or more times by —O—, —S—, —NR.sub.4—, —CO—, —COO— or —OOC—, and is unsubstituted or substituted by cyano, carboxy, hydroxy, C.sub.6-C.sub.10aryl, or C.sub.6-C.sub.10aryloxy, which C.sub.6-C.sub.10aryl or C.sub.6-C.sub.10aryloxy is unsubstituted or substituted by cyano, carboxy, hydroxy, halogen, C.sub.1-C.sub.6alkyl, or C.sub.1-C.sub.6alkoxy; R.sub.3 and R.sub.4 are each independently of the other hydrogen, halogen, nitro, cyano, trifluoromethyl, carboxy, C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.6alkoxy, C.sub.1-C.sub.6alkylcarbonyl, C.sub.6-C.sub.10arylcarbonyl, C.sub.1-C.sub.6alkoxycarbonyl, C—C.sub.6alkylsulfonyl, C.sub.1-C.sub.6alkylsulfonylamino or C.sub.1-C.sub.4alkanoylamino; and R.sub.5 is halogen, nitro, cyano, trifluoromethyl, carboxy, C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.6alkoxy, C.sub.1-C.sub.6alkylcarbonyl, C.sub.6-C.sub.10arylcarbonyl, C.sub.1-C.sub.6alkoxycarbonyl, C.sub.1-C.sub.6alkylsulfonyl, C.sub.1-C.sub.6alkylsulfonylamino or C.sub.1-C.sub.4alkanoylamino; and R.sub.6, R.sub.7, R.sub.8 and R.sub.9 independently of each other are hydrogen, hydroxy, halogen, cyano, nitro or C.sub.1-C.sub.4alkanoylamino, and the radicals X independently denote N or C—H, with the proviso that at least one radical X denotes C—H, which are distinguished by their good lightfastness properties.

##STR00001##

The novel yellow metal azo pigments based on at least three metal azo compounds, which differ at least in the type of metal, have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least three metal azo compounds which differ at least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least three metal azo compounds which differ at least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

The novel yellow metal azo pigments based on at least two metal azo compounds which differ a least in the type of metal have improved colour strengths and are of excellent suitability for pigmentation of pigment preparations for a broad field of use.

Sensors for detecting and distinguishing metals in a sample comprise phenol group-containing azo dyes, the phenol group having one hydroxy involved in reversible metal ion binding and a second hydroxy alkylated to an optically transparent substrate. The sensors have utility for detecting chromium, calcium, magnesium, copper, mercury, nickel, zinc, cobalt, manganese, cadmium, lead, tin, aluminum, potassium, sodium, or arsenic ions in a sample.

An object of the invention is to provide a yellow ink composition for nonaqueous inkjet that achieves excellent density and weather resistance on printed matters whose printing surface is constituted by a polyvinyl chloride polymer, ethylene-vinyl acetate copolymer, or other vinyl polymer or the like, while also ensuring excellent discharge stability, even in a high-speed printing mode. To this end, a yellow ink composition for nonaqueous inkjet is provided that contains, as the pigment, C. I. Pigment Yellow 150 and C. I. Pigment Yellow 83 at a ratio by mass, calculated by C. I. Pigment Yellow 150/C. I. Pigment Yellow 83, of 5/5 to 9/1, and further contains a pigment dispersant, a resin, and an organic solvent.

Disclosed is an azo compound represented by Formula (I)

##STR00001##

in which R.sup.1 is hydrogen or methyl, R.sup.2 is hydrogen or methyl, and R.sup.3 is hydrogen, an unsubstituted linear alkyl group of from 1 to 4 carbon atoms, or an unsubstituted branched alkyl group of from 1 to 9 carbon atoms. This disclosure also provides a black dye composition including the azo compound represented by Formula (I).

Disclosed is an azo compound represented by Formula (I), ##STR00001##
in which R.sup.1 is hydrogen or methyl, R.sup.2 is hydrogen or methyl, and R.sup.3 is hydrogen, an unsubstituted linear alkyl group of from 1 to 4 carbon atoms, or an unsubstituted branched alkyl group of from 1 to 4 carbon atoms. This disclosure also provides a black dye composition including the azo compound represented by Formula (I).

Provided herein are dyes for detecting and distinguishing metals in a sample, as well as compositions and methods comprising the same.

##STR00001## ##STR00002## ##STR00003##