This work proposes the use of multimodal mixtures of monodispersed silica nanoparticles (SiO2-NPs) standards for the simultaneous determination of size and concentration of SiO2-NPs in aqueous suspensions by asymmetric flow field-flow fractionation (AF4) coupled to inductively coupled plasma mass spectrometry (ICPMS). For such a purpose, suspensions of SiO2-NPs standards of 20, 40, 60, 80, 100 and 150 nm were characterised by transmission electronic microscopy (TEM), centrifugal liquid sedimentation (CLS), dynamic light scattering (DLS) and by measuring the Z-potential of the particles as well as the exact concentration of NPs by off-line ICPMS. An on-line AF4-ICPMS method which allowed the separation of all the different sized SiO2-NPs contained in the mixture of standards was developed and the analytical figures of merit were systematically evaluated. The method showed excellent linearity in the studied concentration range (0.1-25 mg L-1), limits of detection between 0.16 and 0.3 mg L-1 for smaller and greater particles, respectively, besides a satisfactory accuracy. AF4 calibration with particles with identical nature to those to be analysed, also permitted accurate size determination in a pragmatic way. Similarly, by using pre-channel calibration with NPs for mass determination it was possible to overcome common quantification problems associated to losses of material during the separation and size-dependent effects. The proposed methodology was successfully applied to the characterisation in terms of size and concentration of aqueous test samples containing SiO2-NPs with monomodal size distributions.

BARAHONA RUIZ Francisco;  GEISS Otmar;  URBAN LOPEZ Patricia;  OJEA JIMENEZ Isaac;  GILLILAND Douglas;  BARRERO Josefa; 

2015-03-30

AMER CHEMICAL SOC

JRC93516

0003-2700,   

http://pubs.acs.org/doi/abs/10.1021/ac504698j,    https://publications.jrc.ec.europa.eu/repository/handle/JRC93516,   

10.1021/ac504698j,