US4239495A — Determination of protein

Claim 1

Independent Claim 107 words

An aqueous reagent system for the quantitative determination of protein, said reagent system having a pH of between about 0 and 1 and comprising a dye structurally represented as: ##STR2## a monobasic strong acid having a pK a of less than 3, a polybasic phosphonic acid, and a water soluble, nonionic surfactant characterized as being a block copolymer containing terminal polyethylene oxide segments separated by a polypropylene oxide segment, said ingredients being present in an amount such that said system exhibits substantially the same reactivity to different proteins and, when mixed with a protein containing sample, forms a stable colored protein dye complex which follows Beer's law.

Claim 2

Dependent Claim 107 words

An aqueous reagent system for the quantitative determination of protein, said reagent system having a pH of between about 0 and 1 and comprising a dye structurally represented as: ##STR2## a monobasic strong acid having a pK a of less than 3, a polybasic phosphonic acid, and a water soluble, nonionic surfactant characterized as being a block copolymer containing terminal polyethylene oxide segments separated by a polypropylene oxide segment, said ingredients being present in an amount such that said system exhibits substantially the same reactivity to different proteins and, when mixed with a protein containing sample, forms a stable colored protein dye complex which follows Beer's law.

Claim 3

Dependent Claim 13 words

The system of claim 1 containing, in addition, a small amount of alcohol.

Claim 4

Dependent Claim 25 words

The system of claim 2 wherein the monobasic acid is HCl , the polybasic acid is nitrilotris (methylene) triphosphonic acid, and the alcohol is methanol.

Claim 5

Dependent Claim 54 words

The system of claim 1 wherein the surfactant has the structure HO(C.sub.2 H.sub.4 O).sub.a (C.sub.3 H.sub.6 O).sub.b (C.sub.2 H.sub.4 O).sub.c H where b is at least 15 and a and c are selected such that (C 2 H 4 O) is between about 20 and 90 percent of the total weight of the compound.

Claim 6

Dependent Claim 26 words

The system of claim 4 wherein, in the surfactant, the polyoxypropylene base molecular weight is about 2050 and the polyoxyethylene content is about 70% by weight.

Claim 7

Independent Claim 56 words

The system of claims 1, 2, 3, 4, or 5 wherein the ingredients are present in the following amounts: (a) the dye--0.005% to 0.05% (W/V), (b) combined polybasic and monobasic acids--2% to 5% (V/V) with the ratio of said polybasic acid to said monobasic acid being between about 2:1 and 3:1, (c) surfactant--0.1% to 0.25% (W/V).

Claim 8

Dependent Claim 19 words

The system of claim 6 wherein alcohol is present in an amount of between about 0.1% and 2% (V/V).

Claim 9

Independent Claim 123 words

A method of assaying protein which comprises the steps of: (a) mixing a protein-containing sample with an aqueous reagent system having a pH of between about 0 and 1, said reagent system comprising a dye structurally represented as: ##STR3## a monobasic strong acid having a pK a of less than 3, polybasic phosphonic acid, and a water soluble, nonionic surfactant characterized as being a block copolymer containing terminal polyethylene oxide segments separated by a polypropylene oxide segment, said ingredients being present in an amount such that said system exhibits substantially the same reactivity to different proteins and, when mixed with said protein-containing sample, forms a stable colored protein-dye complex which follows Beer's law, and (b) observing the resultant color change in said sample.

Claim 10

Independent Claim 123 words

A method of assaying protein which comprises the steps of: (a) mixing a protein-containing sample with an aqueous reagent system having a pH of between about 0 and 1, said reagent system comprising a dye structurally represented as: ##STR3## a monobasic strong acid having a pK a of less than 3, polybasic phosphonic acid, and a water soluble, nonionic surfactant characterized as being a block copolymer containing terminal polyethylene oxide segments separated by a polypropylene oxide segment, said ingredients being present in an amount such that said system exhibits substantially the same reactivity to different proteins and, when mixed with said protein-containing sample, forms a stable colored protein-dye complex which follows Beer's law, and (b) observing the resultant color change in said sample.

Claim 11

Dependent Claim 16 words

The method of claim 8 wherein said reagent system additionally contains a small amount of alcohol.

Claim 12

Dependent Claim 24 words

The method of claim 9 wherein the monobasic acid is HCl, the polybasic acid is nitrilotris (methylene) triphosphonic acid, and the alcohol is methanol.

Claim 13

Dependent Claim 62 words

The method of claim 8 wherein the surfactant has the structure HO(C 2 H 4 O) a (C 3 H 6 O) b (C 2 H 4 O) c where b is at least 15 and a and c are selected such that (C 2 H 4 O) is between about 20 and 90 percent of the total weight of the compound.

Claim 14

Dependent Claim 26 words

The method of claim 11 wherein, in the surfactant, the polyoxypropylene base molecular weight is about 2050 and the polyoxyethylene content is about 70% by weight.

Claim 15

Independent Claim 65 words

The method of claims 8, 9, 10, 11 or 12 wherein the ingredients of said reagent system are present in said reagent system in the following amounts: (a) the dye--0.005% to 0.05% (W/V); (b) combined polybasic and monobasic acids--2% to 5% (V/V) with the ratio of said polybasic acid to said monobasic acid being between about 2:1 and 3:1; and (c) surfactant--0.1% to 0.25% (W/V).

Claim 16

Dependent Claim 23 words

The method of claim 13 wherein alcohol is present in said reagent system in an amount of between about 0.1% and 2% (V/V).

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1983-12-16	1984-06-16	1984-12-16	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1987-12-16	1988-06-16	1988-12-16	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1991-12-16	1992-06-16	1992-12-16	$7700.00	Window Closed / Lapsed

Determination of protein

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