Impact of Ionic Strength of Carrier Liquid on Recovery in Flow Field-Flow Fractionation

Abstract

Asymmetrical flow field-flow fractionation (AF4) and hollow-fiber flow field-flow fractionation (HF5) are techniques widely used in analytical, industrial and biological analyses. The main problem in all AF4 and HF5 analyses is sample loss due to analyte–membrane interactions. In this work the impact of liquid carrier composition on latex nanoparticles (NPs) separation in water and two different concentrations of NH4NO3 was studied. In AF4, a constant trend of decreasing the size of 60 and 121.9 nm particles induced by the ionic strength of the carrier liquid has been observed. In contrast, an agglomeration effect of the biggest 356 nm particles was observed when increasing ionic strength, which induced a significant drop of recovery to 35%. H5F provides better resolution and intensified peaks of NPs, but careful optimisation of system parameters is mandatory to obtain good separation.

Wide-Range Size Fractionation of Graphene Oxide by Flow Field-Flow Fractionation

“…This mechanism generally called a steric/hyperlayer mode is observed for the spherical particles over 1 μm sizes. 31,36,37 It is noteworthy that along with the combination of these two different mechanistic modes, almost the entire size range of GO can be separated by FlFFF, which could be verified by the effective separation of four different representative GO samples with different average sizes, including extra small GO (XSGO), small GO (SGO), medium GO (MGO), and large GO (LGO). Using the different graphite sources, LGO and MGO were synthesized by a modified Hummer's method.…”

“…D is the diffusion coefficient of the sample component (= kT/ 3πηd s ), k is the Boltzmann constant, T is the temperature, η is the viscosity of carrier solution, and d s is the Stokes′ diameter (or the hydrodynamic diamneter). 31 However, the retention ratio in the steric/hyperlayer mode is expressed as…”

“…Additionally, the composition, ionic strength, and pH of the carrier solution affect the electrical double layer of the sample in FlFFF separation. 31 Consequently, various factors such as the channel void volume, crossflow rate, migration flow rate, viscosity of the solution, and Stokes' diameter of analyte should be considered for an optimum size selection condition. 32 To the best of our knowledge, GO size fractionation based on the FlFFF system has not been reported thus far.…”

Development of methods for extraction and analytical characterization of carbon-based nanomaterials (nanoplastics and carbon nanotubes) in biological and environmental matrices by asymmetrical flow field-flow fractionation

“…The R rms for 600 populations signal showed that steric transition might have happened. Steric mode of separation in AF4 occurs when the size of particles increase and, consequently, the diffusion coefficient decreases, thus, the separation sequence is inverted and the larger particles elute before the smaller particles (Kowalkowski et al, 2018). Similarly, Correia et al (2018) reported that NMs extracted from complex matrices eluted following the steric separation when the particle size increased to larger than 300 nm.…”

An effective solution to simultaneously analyze size, mass and number concentration of polydisperse nanoplastics in a biological matrix: asymmetrical flow field fractionation coupled with a diode array detector and multiangle light scattering

“…To separate polydisperse PS NPs using AF4, cross ow and detector ow, focus ow and time, and carrier composition and concentration require optimization. 33,34 The composition and concentration of carrier uid is undoubtedly crucial and should be carefully investigated rstly. The optimum carrier uid should avoid the particles agglomeration (obtaining the correct size), particles loss (obtaining high signal) and obtain effective separation among particles (resolution > 1.0).…”