Colorimetric determination of calcium in biologic fluids

Claim 2

ThE process of claim 1 wherein, before colorimetric analysis, a high molecular weight, calcium free micelle forming protective colloid is added to the biologic fluid to hold lipids in solution.

Claim 3

The process of claim 3 wherein the protective colloid is selected from polyvinylpyrrolidone and epoxide copolymers.

Claim 4

The process of claim 1 wherein, before colorimetric analysis, a reducing agent is added to the biologic fluid to stabilize the color of the calcium-dye complex.

Claim 5

The process of claim 5 wherein the reducing agent is sodium sulfite.

Claim 6

The process of claim 1 wherein during colorimetric analysis the pH of the biologic fluid is maintained at about 10-13 with monoethanol amine.

Claim 7

The process of claim 1 wherein the reagent dye is selected from methylthymol blue and methylxylenol blue.

Claim 8

The process of claim 8 wherein, before colorimetric analysis, 8-quinolinol is added to the biologic fluid in an amount sufficient to complex with magnesium present therein and a high molecular weight, calcium free micelle forming protective colloid is added to the biologic fluid to hold lipids in solution.

Claim 9

The process of claim 9 wherein the protective colloid is selected from polyvinylpyrrolidone and epoxide copolymers.

Claim 10

The process of claim 10 wherein a reducing agent is added to the biologic fluid to stabilize the color of the calcium-dye complex.

Claim 11

The process of claim 11 wherein the reducing agent is sodium sulfite.

Claim 12

The process of claim 12 wherein during colorimetric analysis of pH of the biologic fluid is maintained at about 10-13 with monoethanol amine.

Claim 13

The process of claim 13 wherein the protective colloid is polyvinylpyrrolidone.

Claim 14

The process of claim 14 wherein the standard aqueous solutions containing known calcium concentrations also contain the reagent dye, the polyvinylpyrrolidone protective colloid and the sodium sulfite reducing agent in concentrations substantially the same as those present in the biologic fluid being analyzed.

Claim 15

A stable aqueous dye solution useful in the colorimetric determination of calcium in biologic fluids, said solution consisting essentially of (A) water, (B) a reagent dye of phenol-sulphonephthalein containing methylenenitrilodiacetic acid group substituents in the 6, 6''-positions on the phenol rings and non-calcium binding substituents in the 2,2'' and 5,5,''-positions thereon with said 2, 2'' and 5, 5''-position substituents serving to shift the characteristic wave length of maximum light absorption of the dye when complexed with a calcium to greater than about 590 nm., (C) a high molecular weight calcium free, micelle forming non-ionic protective colloid, and (D) an acid having a water soluble calcium salt, the acid being present in an amount sufficient to give a solution pH of less than about 4.

Claim 16

The dye solution of claim 16 wherein the protective colloid is selected from polyvinylpyrrolidone, and expoxide copolymers.

Claim 17

The dye solution of claim 17 wherein the reagent dye is selected from methylthymol blue and methylxylenol blue and, based on one litter of solution, the protective colloid is present in an amount of about 3-9 grams and the reagent dye is present in an amount of about 0.15-0.25 millimole.

Claim 18

The dye solution of claim 18 wherein the protective colloid is polyvinylpyrrolidone and the reagent dye is methylthymol blue.

Claim 19

The dye solution of claim 19 wherein the acid is hydrochloric acid.

Claim 20

The dye solution of claim 16 containing in addition to the recited ingredients a magnesium complexing agent.

Claim 21

The dye solution of claim 21 wherein the magnesium complexing agent is 8-quinolinol.

Claim 22

The dye solution of claim 22 wherein, per liter of solution, 8-quinolinol is present in an amount of about 23-75 millimoles.

Claim 23

The dye solution of claim 23 wherein the protective colloid is selected from polyvinylpyrrolidonE, and epoxide copolymers.

Claim 24

The dye solution of claim 24 wherein the reagent dye is selected from methylthymol blue and methylxylenol blue and, based on one liter of solution, the protective colloid is present in an amount of about 3-9 grams and the reagent dye is present in an amount of about 0.15-0.25 millimole.

Claim 25

The dye solution of claim 25 wherein the protective colloid is polyvinylpyrrolidone and the reagent dye is methylthymol blue.

Claim 26

The dye solution of claim 26 wherein the acid is hydrochloric acid.

Claim 27

The process of claim 1 wherein the reagent dye is methylthymol blue.