2.5. Column Preparation and Preconcentration ProcedureA selleck chem Carfilzomib short glass column with an inner diameter of 0.5cm and a length of 50cm, equipped with porous frits was filled up to a height of about 0.3cm with a suspension of 0.08g of proposed sorbent. Palladium nanoparticles silica-bonded N-propyl morpholine- (PdNP-SBNPM) bonded silica gel preconditioned by the blank solution prior to application, and the column was rinsed with water and stored for application.2.6. Preconcentration ProcedureThe pH of the solution (250�C2000mL) was adjusted to 7.0 (by addition of dilute HNO3 or NaOH) and passed through the column compromise of 0.08g of this new sorbent at flow rate of 4mLmin?1. The adsorbed analytes eluted with 8mL of 5M HCl, and their metal ions content were measured by flame atomic absorption spectroscopy (FAAS).
3. Results and Discussion3.1. Characterization of Proposed SorbentThe EDX spectrum (Figure 2(b) and Table 1) shows 0.0516g of palladium for 1g of proposed sorbent. The XRD pattern of the PNP-SBNPM catalyst (Figure 2(c)) also shows presence of palladium nanoparticle on silica surface. The strongest peaks of the XRD pattern correspond to the SiO2, and other peaks are indexed as the (111), (200), (220), (311), and (222) planes belonging to palladium nanoparticle. Transmission electron microscopy (TEM) image of PNP-SBNPM as a new sorbent (Figure 3(a)) shows that the Pd nanoparticles with near spherical morphology are assembled onto silica bonded N-propyl morpholine support with a relatively good monodispersity (��0.8) and an average size of 7nm.
The microscopic features of the catalyst were observed with scanning electron microscopy (SEM) (Figure 3(b)) which efficiently shows the morphology of the silica substrate. A BET surface area of 120m2g?1 and Entinostat a total pore volume of 0.11cm3g?1 were measured for this new sorbent. Figure 4 shows the pore size distribution curve of adsorbents based on the nitrogen equilibrium adsorption isotherm at 77K, which shows the fine homogenous structure of this new sorbent and efficient immobilization of morpholine and attachment of palladium to the support surface. Table 1 showed the elemental composition of the sample and attachment of palladium nanoparticle to support surface. The support material in SPE should be thermally and chemically stable during the reaction process, and its active sites must be well dispersed on its surface and be easily accessible. Thus, the chemical modification and simultaneous attachment of palladium nanoparticle seems to be efficient pathway for producing new sorbent.Figure 3(a) TEM, which shows the image of Pd nanoparticle, (b) SEM of PNP-SBNPM (magnification of 500).