Colorimetric assay for bilirubin
First Claim
1. A colorimetric method for the detection of bilirubin in an aqueous liquid which comprisesa. contacting in a reagent zone said aqueous liquid and an interactive mordant composition for bilirubin, such interactive mordant composition having one or more binding sites for bilirubin and comprising a hydrophobic organic matrix and at least one charge-bearing cationic group,whereby bilirubin is mordanted, said mordanted bilirubin exhibiting an absorption peak shifted at least about 10 nm. from that of free bilirubin and a molar extinction coefficient at least about 50 percent higher than that of free bilirubin, andb. colorimetrically detecting said mordanted bilirubin.
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Abstract
A colorimetric assay method for the detection of bilirubin in various liquid samples, particularly biological liquids. A multi-zone analytical element based on this assay method is also disclosed. The assay method employs an interactive mordant composition for bilirubin having one or more binding sites for bilirubin, such composition comprising a hydrophobic organic matrix and at least one charge-bearing cationic group. Upon mordanting of bilirubin by the interactive mordant composition, the mordanted bilirubin exhibits an absorption peak shift of at least 10 nm. and at least a 50% increase in molar extinction coefficient.
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Citations
23 Claims
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1. A colorimetric method for the detection of bilirubin in an aqueous liquid which comprises
a. contacting in a reagent zone said aqueous liquid and an interactive mordant composition for bilirubin, such interactive mordant composition having one or more binding sites for bilirubin and comprising a hydrophobic organic matrix and at least one charge-bearing cationic group, whereby bilirubin is mordanted, said mordanted bilirubin exhibiting an absorption peak shifted at least about 10 nm. from that of free bilirubin and a molar extinction coefficient at least about 50 percent higher than that of free bilirubin, and b. colorimetrically detecting said mordanted bilirubin.
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10. An element for the colorimetric detection of bilirubin in an aqueous liquid, said element having a spreading zone and a reagent zone in fluid contact under conditions of use, said element free from any reagent zone which contains highly colored dyestuff or fluorescent probe materials or precursors for such materials, said reagent zone comprising an interactive mordant composition for bilirubin, such interactive mordant composition
a. having one or more binding sites for bilirubin and comprising a hydrophobic organic matrix and at least one charge-bearing cationic group, and b. upon mordanting bilirubin, exhibiting an absorption peak shifted at least about 10 nm. from that of free bilirubin and a molar extinction coefficient at least about 50 percent higher than that of free bilirubin.
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14. An integral element for the detection of bilirubin in an aqueous liquid, said element comprising a spreading layer superposed over a reagent layer carried on a radiation transmissive support, said element free from any reagent layer which contains a highly colored dyestuff or fluorescent probe material or precursors for such materials, said spreading layer and reagent layer in fluid contact under conditions of use, said spreading layer comprising an isotropically porous, non-fibrous composition containing an amount of surfactant effective to normalize transport of bilirubin through said layer, said reagent layer comprising an interactive mordant composition for bilirubin, such interactive composition
a. upon mordanting bilirubin, exhibiting an absorption peak shifted at least about 10 nm. from that of free bilirubin and a molar extinction coefficient at least about 50 percent higher than that of free bilirubin, and b. comprising a polymeric material having repeating units of the following formula: - ##STR13## wherein A represents an alkylene group, Q represents a hydrocarbon having a group linking the nitrogen atom to A and containing from about 5 to about 10 carbon atoms, each of R1, R2, and R3, which may be the same or different, represents an alkyl having from 1 to less than about 10 carbon atoms or an aryl, aralkyl or alkaryl having from 5 to less than about 20 carbon atoms, and X- represents an acid anion.
- View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
Specification