Functionalization of multiwalled carbon nanotubes for the solid-phase extraction of silver, cadmium, palladium, zinc, manganese and copper by flame atomic absorption spectrometry

Abstract

In the present work, multiwalled carbon nanotube (MWCNT) chemically modified with (3-mercaptopropyl) silanetriolate is efficiently used for the solid-phase extraction of Cu(2+), Ag(+), Cd(2+), Pb(2+), Zn(2+) and Mn(2+) ions prior to their flame atomic absorption spectrometric determination. The influences of the various analytical parameters, including pH, amounts of solid phase, sample volume and eluent conditions and so on, on the recoveries of target analytes were investigated and optimized by one at a time optimization method. The influences of alkaline, alkaline earth and some transition metals on the adsorption and elution of the analytes were also examined. The detection limits for all understudied metal ions were between 1.4 and 2.8 ng mL(-1) (3Sb, n = 10). The evaluation of the thermodynamic parameters such as enthalpy (positive value), Gibbs free energy (negative value) in addition to high value of entropy shows the endothermic and spontaneous nature of sorption process. Following the optimization of variables, the adsorption process follows the intraparticle kinetic model with R (2) of 0.98 and the Langmuir isotherm with high correlation coefficient (R (2) > 0.95). The procedure was applied for the analytes determination in the food samples with satisfactory results (recoveries >95% and relative standard deviation's (RSD) lower than 4%).

Recent advances in applications of nanomaterials for sample preparation

“…For metal ion analysis, multiple chelating reagents or thiolation reagents such as bis(5-bromosalicylidene)-1,3-propandiamine [18], diphenylcarbazide [19], dimethyl acetylenedicarboxylate [20] and (3-mercaptopropyl) silanetriolate [21] were coupled to the surfaces of CNPs to extract metal ions with improved selectivity. In addition, to eliminate interferences originated from sample matrix in metal ion analysis, CNPs could also be modified with matrix-excluded coatings such as restricted access carbon nanotubes (RACNTs) [22].…”

Determination of Cd(II), Zn(II) and Ag(I)in Different Matrixes After Solid Phase Extraction on Sodium Dodecyl Sulfate(SDS)-Coated Alumina as their 2,3 Di Hydro 2,3 ParatolylQinazoline (1 H)- 4 one (DPTQO) by FlameAtomic Absorption Spectrometric

“…Stock solutions of all understudy elements were prepared by dissolving appropriate amount of ultrapure salt obtained from Merck (Darmstadt, Germany) in 4M HNO 3 26 .…”

“…After mixing for15 min, the supernatant solution was discarded and the remaining was used as modified solid phase. The solid phase was purified by passing 4mL of 4 mol L -1 HNO 3 and neutralized with 0.1mol L -1 KOH. The sorbent in refrigerator is stable for at leastone month.…”

“…Therefore determination of trace heavy metals in different environmental samples is of great interest to analytical chemists. Recently, solid phase extraction has been successfully utilized for the preconcentration and separation of trace metal ions 3,4 . These difficulties and limitations can be overcome with doing a preliminary separation and/or preconcentration step and subsequent measurement by FAAS to decrease the matrix interference (by its simplification) or improve in the detection limit 5,6 .…”

Preparation and characterization of MWCNTs functionalized by N-(3-nitrobenzylidene)-N′-trimethoxysilylpropyl-ethane-1,2-diamine for the removal of aluminum(iii) ions via complexation with eriochrome cyanine R: spectrophotometric detection and optimization

“…[14][15][16][17] Chemical modification of MWCNT with different chelating agents or complexation centers significantly changes its nature, increases the number of reactive functional groups as well as enhances its selectivity and sorption capacity. [17][18][19][20][21][22][23] The rate of adsorption can be accelerated by ultrasound irradiation via the enhancement in the mass transfer due to high-pressure shake waves and high-speed micro jets appeared following violent collapse of cavitations' bubbles. 24,25 In this work, MWCNT was modified with Schiff base-like structure following its reaction with N-(3-Nitro-benzylidene)-N'-trimethoxysilylpropyl-ethane-1,2-diamine (NBATSPED-MWCNT) as a novel adsorbent followed by the characterization using different techniques such as Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis-differential thermal analysis (TGA-DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM).…”