Methods of isolating and detecting metal ions from proteins
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Publication Number
US-10451599-B2
Publication Date
2019-10-22
Expiration Date
Abstract
A method of detecting a metal ion in a protein-containing sample includes adding a protein degrading enzyme to the protein-containing sample to form an enzyme degradation product, adding an acid to the enzyme degradation product to provide a mixture, filtering the mixture to provide a supernatant, extracting the supernatant with an organic solvent to remove organic solvent soluble byproducts to provide a washed aqueous layer, and detecting the metal ion in the washed aqueous layer. The method is amenable to the detection of heavy metal ions in complex products such as milk. A kit includes reagents for performing the method.
Core Innovation
The described invention relates to methods and kits for isolating and detecting metal ions, including heavy metal ions such as lead and uranium, from protein-containing samples such as milk. The workflow uses a protein-degrading enzyme and steps intended to isolate the metal ions while removing protein-containing components and other interfering materials. Detection is performed with a handheld device based on giant magnetoresistance (GMR), with fluorescence detection also described in the provided content.
A protein-degrading enzyme, for example proteinase K, is used in combination with concentrated nitric acid to denature and de-emulsify in a manner that supports subsequent separation. Filtering removes proteins and lipids, producing a washed aqueous layer. The metal ions are then extracted and/or concentrated into the aqueous layer for detection, with organic-soluble byproducts removed by an organic solvent extraction.
The provided content states that the approach includes considerations of acid choice, solvent choice, and filter type, and it reports quantitative detection results for Pb2+ and UO2^2+. The invention also notes optional omission of steps depending on sample type and optional denaturants or surfactants to address interference from DNA/RNA/protein.
Claims Coverage
The partial content identifies one independent claim defining a kit for isolating metal ions from a protein-containing sample, with detection based on a handheld giant magnetoresistance (GMR) device. The independent claim is complemented by dependent claims that refine the kit for field use and add protein denaturing agents.
Kit with GMR-based handheld metal-ion detection and isolation instructions
A kit comprising a container for holding a protein-containing sample, proteinase K, concentrated nitric acid, chloroform, and a handheld device for detecting metal ions employing detection based on giant magnetoresistance, together with instructions for performing the isolation of metal ions from the protein-containing sample.
Across the identified independent claim and refinements, the claimed scope centers on a kit that combines specified reagents (proteinase K, concentrated nitric acid, and chloroform) with a handheld GMR-based metal-ion detection device and provides instructions for isolating metal ions from protein-containing samples. Dependent claims further specify field/small-scale use and add other protein denaturing agents, including selections from SDS, urea, EDTA, trypsin, and chymotrypsin.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Isolation and detection of heavy metal ions (e.g., lead (Pb2+) and uranium (UO2^2+)) from protein-containing samples such as milk.
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