Performance evaluation of flow field-flow fractionation and electrothermal atomic absorption spectrometry for size characterization of gold nanoparticles

Abstract

Flow field-flow fractionation (Fl-FFF) coupled off-line with electrothermal atomic absorption spectrometry (ETAAS) was applied for particle size characterization of gold nanoparticles (AuNPs). Effects of carrier liquid and membranes on the Fl-FFF separation performance were studied in order to achieve the best separation condition for AuNPs before ETAAS analysis. The separation of AuNPs was investigated with the use of 10 kDa regenerated cellulose (RC) and 10 kDa polyethersulfone (PES) membrane and three types of carrier solution including deionized water (DI water), 0.05% SDS (sodium dodecyl sulfate), and 0.02% FL-70 with 0.02% NaN₃. Using DI water with 10 kDa RC membrane provided the best separation performance for AuNPs. Fractions eluted from Fl-FFF were collected and introduced into ETAAS for gold detection. With ETAAS, the time at the maximum absorbance increased when the particle size increased. The in-house synthesized AuNPs were characterized by using Fl-FFF with ETAAS, dynamic light scattering (DLS), and transmission electron microscopy (TEM) technique and the results obtained were in good agreement. Statistical comparison between Fl-FFF and DLS (t_experiment = 1.02), ETAAS after Fl-FFF and TEM (t_experiment = 0.96) showed no significant difference using paired t-test with the critical value of t as 4.30 (P = 0.05). The experimental results indicated that the size of AuNPs from two methods, Fl-FFF with DLS for hydrodynamic diameter and ETAAS with TEM for core size, were not significantly different at P = 0.05.

Keywords: Carrier liquid; Core size; Electrothermal atomic absorption spectrometry; Flow field-flow fractionation; Gold nanoparticles; Hydrodynamic diameter.