Method and compositions for enhancing aminolevulinic acid dehydratase assay
AssigneeAbbott Laboratories
InventorsMartin Wong, David M. Finley
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Abstract
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.
Claims28
A lead assay comprising the steps of:
- (a) providing an aqueous solution suspected of containing lead;
- (b) isolating said lead from said solution in such a manner that said lead remains in solution;
- (c) introducing to said solution of step (b) an enhancing reagent that combines with said lead and prevents said lead from precipitating from said solution;
- followed by
- (d) introducing to said solution an enzyme the activity of which is inhibited in the presence of lead and a substrate for said enzyme;
- and
- (e) measuring the amount of lead as a function of said activity of said enzyme.
A lead assay comprising the steps of:
- (a) providing an aqueous solution suspected of containing lead, said solution having been separated from compounds that are affected by the presence of lead, said solution further having been neutralized;
- (b) introducing into said solution a lead chelator having a lead equilibrium binding constant in the range of about 4 log K to about 13 log K;
- followed by
- (c) introducing into said solution (i) an enzyme the activity of which is inhibited by lead and (ii) a substrate which reacts with the enzyme;
- (d) incubating the solution of step (c);
- (e) stopping the incubation step after a predetermined interval;
- and
- (f) measuring the amount of lead as a function of enzyme activity.
An aqueous lead assay reagent solution consisting essentially of neutralizing buffer and a lead chelator having a lead binding constant in the range of about 4 log K to about 13 log K wherein the concentration of the chelator in the solution is in the range of 0.5 mM to 500 mM.
A lead assay reagent kit comprising:
- a container having a reagent solution consisting essentially of an aqueous neutralizing buffer and present therein a reagent which is capable of forming a compound or complex with lead such that adding the solution to an acidified aqueous sample containing lead will neutralize the aqueous sample while preventing precipitation of lead therefrom;
- a container comprising an enzyme which is inhibited in the presence of lead;
- and
- a container comprising a substrate which reacts with said enzyme.
Dependencies are inferred from the claim text.