Patent ID: 7629179

Claim:
A method for direct detection of a trace element, the method comprising: (a) linking a surface of a nanoparticle with a compound to form a nanoparticle-linked compound, wherein the compound is selected from a group consisting of: 2,3-diaminonapthalene (DAN); 3,3,′-diaminobenzidine (DAB); 4-[bis(carboxymethyl)-aminomethyl]-3-hydroxy-2-naphthoic acid (DHNA); acetic acid, 3,3′-[vinylenebis[(6-hydroxy-m-phenylene)methylenenitrilo]]tetra-, E-(8CI) (BDDS); 8-amino-3,7,-dimethyl-10-phenyl-10H-phenazion-2-ylidene ammonium ion; 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-5-(2-hydroxyethyl)-4-methylthiazolium (thiamine); carboxymethyl-[4-[10-(4-dicarboxymethylaminobenzyl)anthracen-9-ylmethyl]phenyl]amino) acetic acid dipotassium salt (CDAPAP); and NMBDA, wherein NMBDA is a compound of the formula: (b) incubating a sample containing the trace element with the nanoparticle-linked compound for a time sufficient to bind the trace element to the nanoparticle-linked compound to form a trace element bound nanoparticle-linked compound, wherein the trace element is selected from a group consisting of selenium, beryllium, cadmium, chromium, mercury, zinc, and calcium, and wherein the trace element bound nanoparticle-linked compound is selected from a group consisting of: nanoparticle-linked 2,3-diaminonapthalene (DAN) bound to selenium; nanoparticle-linked 3,3,′-diaminobenzidine (DAB) bound to selenium; nanoparticle-linked 4-[bis(carboxymethyl)-aminomethyl]-3-hydroxy-2-naphthoic acid (DHNA) bound to beryllium; nanoparticle-linked acetic acid, 3,3′-[vinylenebis[(6-hydroxy-m-phenylene)methylenenitrilo]]tetra-, E-(8CI) (BDDS) bound to cadmium; nanoparticle-linked 8-amino-3,7,-dimethyl-10-phenyl-10H-phenazion-2-ylidene ammonium ion bound to chromium; nanoparticle-linked 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-5-(2-hydroxyethyl)-4-methylthiazolium (thiamine) bound to mercury; nanoparticle-linked carboxymethyl-[4-[10-(4-dicarboxymethylaminobenzyl)anthracen-9-ylmethyl]phenyl]amino) acetic acid dipotassium salt (CDAPAP) bound to zinc; and nanoparticle-linked NMBDA bound to calcium, wherein NMBDA is a compound of the formula: (c) exposing the trace element bound nanoparticle-linked compound to light having a wavelength that excites the trace element bound nanoparticle-linked compound; and (d) detecting a fluorescent signal emitted by the trace element bound nanoparticle-linked compound.