title: Direct detection of Pb in urine and Cd, Pb, Cu, and Ag in natural waters using electrochemical sensors immobilized with DMSA functionalized magnetic nanoparticles.
abstract: Urine is universally recognized as one of the best non-invasive matrices for biomonitoring exposure to a broad range of xenobiotics, including toxic metals. Detection of metal ions in urine has been problematic due to the protein competition and electrode fouling. For direct, simple, and field-deployable monitoring of urinary Pb, electrochemical sensors employing superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) has been developed. The metal detection involves rapid collection of dispersed metal-bound nanoparticles from a sample solution at a magnetic or electromagnetic electrode, followed by the stripping voltammetry of the metal in acidic medium. The sensors were evaluated as a function of solution pH, the binding affinity of Pb to DMSA-Fe3O4, the ratio of nanoparticles per sample volume, preconcentration time, and Pb concentrations. The effect of binding competitions between the DMSA-Fe3O4 and urine constituents for Pb on the sensor responses was studied. After 90 s of preconcentration in samples containing 25 vol.% of rat urine and 0.1 g L(-1) of DMSA-Fe3O4, the sensor could detect background level of Pb (0.5 ppb) and yielded linear responses from 0 to 50 ppb of Pb, excellent reproducibility (%RSD of 5.3 for seven measurements of 30 ppb Pb), and Pb concentrations comparable to those measured by ICP-MS. The sensor could also simultaneously detect background levels (<1 ppb) of Cd, Pb, Cu, and Ag in river and seawater.
authors.affiliation: Pacific Northwest National Laboratory, Richland, WA 99352, USA. wassana.yantasee@pnl.gov
authors.forename: Wassana
authors.initials: W
authors.lastname: Yantasee
authors.forename: Kitiya
authors.initials: K
authors.lastname: Hongsirikarn
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Warner
authors.forename: Daiwon
authors.initials: D
authors.lastname: Choi
authors.forename: Thanapon
authors.initials: T
authors.lastname: Sangvanich
authors.forename: Mychailo B
authors.initials: MB
authors.lastname: Toloczko
authors.forename: Marvin G
authors.initials: MG
authors.lastname: Warner
authors.forename: Glen E
authors.initials: GE
authors.lastname: Fryxell
authors.forename: R Shane
authors.initials: RS
authors.lastname: Addleman
authors.forename: Charles
authors.initials: C
authors.lastname: Timchalk
mesh_terms: D000818:Animals; D002104:Cadmium / Q000032:analysis; D002614:Chelating Agents; D003300:Copper / Q000032:analysis; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis / Q000652:urine*; D005290:Ferric Compounds; D007854:Lead / Q000032:analysis / Q000652:urine*; D008280:Magnetics; D053768:Metal Nanoparticles; D019216:Metals, Heavy / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012834:Silver / Q000032:analysis; D004113:Succimer; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D002614:Chelating Agents; D004785:Environmental Pollutants; D005290:Ferric Compounds; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002104:Cadmium; C000499:ferric oxide; D007854:Lead; D012834:Silver; D003300:Copper; D004113:Succimer