title: Mercury determination in urine samples by gold nanostructured screen-printed carbon electrodes after vortex-assisted ionic liquid dispersive liquid-liquid microextraction.
abstract: A novel approach is presented to determine mercury in urine samples, employing vortex-assisted ionic liquid dispersive liquid-liquid microextraction and microvolume back-extraction to prepare samples, and screen-printed electrodes modified with gold nanoparticles for voltammetric analysis. Mercury was extracted directly from non-digested urine samples in a water-immiscible ionic liquid, being back-extracted into an acidic aqueous solution. Subsequently, it was determined using gold nanoparticle-modified screen-printed electrodes. Under optimized microextraction conditions, standard addition calibration was applied to urine samples containing 5, 10 and 15 μg L(-1) of mercury. Standard addition calibration curves using standards between 0 and 20 μg L(-1) gave a high level of linearity with correlation coefficients ranging from 0.990 to 0.999 (N = 5). The limit of detection was empirical and statistically evaluated, obtaining values that ranged from 0.5 to 1.5 μg L(-1), and from 1.1 to 1.3 μg L(-1), respectively, which are significantly lower than the threshold level established by the World Health Organization for normal mercury content in urine (i.e., 10-20 μg L(-1)). A certified reference material (REC-8848/Level II) was analyzed to assess method accuracy finding 87% and 3 μg L(-1) as the recovery (trueness) and standard deviation values, respectively. Finally, the method was used to analyze spiked urine samples, obtaining good agreement between spiked and found concentrations (recovery ranged from 97 to 100%).
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología e Instituto Universitario de Materiales, Universidad de Alicante, P.O. Box 99, E-03080, Alicante, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Fernández
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología e Instituto Universitario de Materiales, Universidad de Alicante, P.O. Box 99, E-03080, Alicante, Spain. Electronic address: lorena.vidal@ua.es.
authors.forename: Lorena
authors.initials: L
authors.lastname: Vidal
authors.affiliation: Departamento de Química Física y Analítica, Universidad de Oviedo, C/Julián Clavería, 8, 33006 Oviedo, Spain.
authors.forename: Agustín
authors.initials: A
authors.lastname: Costa-García
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología e Instituto Universitario de Materiales, Universidad de Alicante, P.O. Box 99, E-03080, Alicante, Spain. Electronic address: a.canals@ua.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Canals
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D006046:Gold / Q000737:chemistry*; D055768:Halogenated Diphenyl Ethers / Q000032:analysis*; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis*; D049329:Nanostructures; D015203:Reproducibility of Results; D012722:Sewage / Q000737:chemistry*
chemical_list: D055768:Halogenated Diphenyl Ethers; D012722:Sewage; D006046:Gold; D008628:Mercury
keywords: Ionic liquid; Mercury; Screen-printed electrodes; Urine samples; Vortex-assisted dispersive liquid–liquid microextraction