| Recently, the application of nano-materials into solid-phase extraction has attracted great attention due to their big specific surface area, high adsorption capacity, rapid adsorption process, etc.In this study, magnetic MWCNTs (NiFe2O4/MWCNTs), nano-Al2O3, hollow porous carbon spheres (HPCSs) were used as solid-phase extraction sorbent for the determination of tenofovir disoproxil fumarate (TDF), colorants (tartrazine and sunset yellow) and nine bisphenols, respectively. The primary research work is as follows:1. Magnetically separable NiFe2O4/multiwalled carbon nanotubes (NiFe2O4/MWCNTs) adsorbent was successfully synthesized and characterized. Adsorption kinetics and thermodynamics was investigated, indicating that the magnetic MWCNTs showed excellent adsorption capacity and fast adsorption kinetics to TDF. The extraction efficiency was over 95%. The ionic liquid [Cgmim][PF6] was used to substitute for toxic and environmentally hazardous solvents as the green eluent, obtaining recovery of over 92%. Analytical parameters of the NiFe2O4/MWCNTs-based M-d-SPE method were investigated and good linear range (4.0-400.0 ng mL-1), limits of detection (LOD,0.67 ng ml/1), limits of quantification (LOQ,2.2 ng mL-1) and precision (RSD of 6.7%, n= 5) were obtained. This proposed method was successfully applied to the analysis of the real samples with good spiked recoveries over the range of 91.4-99.6%, proving that this method was competitive in practical applications.2. A new micro-solid-phase extraction method based on prestructured membrane filter was developed to facilitate simultaneous analysis of tartrazine (TA) and sunset yellow (SY) with HPLC. Membrane filter impregnated with nano-Al2O3 particles was proposed as a new micro-solid-phase extraction (Filter membrane-μ-SPE) device for the preconcentration of colorants in food. The method integrated isolation and concentration in one step, and the adsorbed colorants could be easily eluted from membrane filters for HPLC analysis. Several experimental parameters, including the type of sorbent, nano-Al2O3 amount dispersed on filter membrane, sample pH and ionic strength and desorption conditions were investigated and optimized. Under optimum condition, the method showed good linearity, with correlation coefficients >0.9982 in the range of 1.0-200.0 ng mL"1, and low limits of detection (0.10-0.20 ng mL-1). Finally, the recovery values were 86.9-124.0%for TA and SY in various food samples. The results indicated that the developed method would be a novel and simple method for rapid determination of TA and SY at trace levels in real samples.3. An extended one-step Stober method was utilized for the preparation of core@shell spheres, which was made up of a thin layer of resorcinol-formaldehyde (RF) and a silica core. After the carbonization and template-removal process, HPCSs were synthesized. The textures of HPCSs were investigated by SEM, TEM and N2 adsorption/desorption isotherms. The results showed that the HPCSs were in good sphere shape with uniform size, high surface areas as well as hollow pores, which(HPCSs) exhibited superior extraction ability for bisphenols (BPs). HPCSs showed extremely high extraction efficiency for BPs as well as outstanding adsorption capabilities due to its hollow porous structure. It was applied as adsorbent for the enrichment of BPs from tap water, environmental water and soft drinks prior to high performance liquid chromatographic analysis, obtaining recoveries ranging from 83.5% to 129.9% with RSD lower than 5.6% and LOQs in the range of 0.183-2.351 ngmL-1. |
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