title: Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry.
abstract: Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches.
authors: Department of Physical and Analytical Chemistry, University of Oviedo, Avda, Julian Claveria 8, 33006 Oviedo, Spain.
authors: Mario
authors: M
authors: Menendez-Miranda
authors: Department of Physical and Analytical Chemistry, University of Oviedo, Avda, Julian Claveria 8, 33006 Oviedo, Spain.
authors: Maria T
authors: MT
authors: Fernandez-Arguelles
authors: Department of Physical and Analytical Chemistry, University of Oviedo, Avda, Julian Claveria 8, 33006 Oviedo, Spain. Electronic address: jcostafe@uniovi.es.
authors: Jose M
authors: JM
authors: Costa-Fernandez
authors: Department of Physical and Analytical Chemistry, University of Oviedo, Avda, Julian Claveria 8, 33006 Oviedo, Spain.
authors: Jorge Ruiz
authors: JR
authors: Encinar
authors: Department of Physical and Analytical Chemistry, University of Oviedo, Avda, Julian Claveria 8, 33006 Oviedo, Spain. Electronic address: asm@uniovi.es.
authors: Alfredo
authors: A
authors: Sanz-Medel
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D005453:Fluorescence; D031521:Fractionation, Field Flow; D013058:Mass Spectrometry / Q000379:methods*; D046529:Microscopy, Electron, Transmission; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C058667:cadmium selenide; C031238:zinc sulfide
keywords: Asymmetric flow field-flow fractionation; Nanoparticles; Quantum dots; Triple quadrupole inductively coupled plasma mass spectrometry