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United States Patent | 5,631,139 |
Wong ,   et al. | May 20, 1997 |
The present invention provides a method of improving the sensitivity and accuracy of a lead assay. The method enhances the recovery of lead during isolation of the lead from interfering compounds by maintaining the lead in a sample solution and making the recovered lead available for detection by the assay. An enhancing reagent complexes with the lead isolated in the sample solution. The enhancer includes a chelator having a lead equilibrium binding constant in the range of about 4 log K to about 13 log K. A kit for performing such a lead assay is also provided.
Inventors: | Wong; Martin (Grayslake, IL); Finley; David M. (Spring Grove, IL) |
Assignee: | Abbott Laboratories (Abbott Park, IL) |
Appl. No.: | 507168 |
Filed: | July 26, 1995 |
Intern'l Class: | C12Q 001/34; G01N 033/00 |
Field of Search: | 435/18,4,268,810,962,963 436/63,73,74,76 514/836 |
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Foreign Patent Documents | |||
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TABLE 1 ______________________________________ Absorbance Pb.sup.+2 Equilibrium Enhancer Conc. mM Span Constant log(Km) ______________________________________ Control -- 0.006 -- Na Citrate 250.00 0.106 4.3 Histidine 250.00 0.915 6.4 IDA 250.00 0.801 7.5 MIDA 100.00 0.735 8.0 HQSA 2.50 0.891 8.5 HEIDA 250.00 0.223 9.5 NTA 10.00 0.110 11.6 Penicillamine 100.00 0.311 13.0 EGTA 10.00 0.016 14.7 ______________________________________