Vortex-assisted restricted access-based supramolecular solvent microextraction of trace Pb(II) ions with 4-(benzimidazolisonitrosoacetyl)biphenyl as a complexing agent before microsampling flame AAS analysis.

A new oxime compound, 4-(benzimidazolisonitrosoacetyl)biphenyl (BIBP) was synthesized and used as a complexing agent in this study to preconcentrate trace amounts of Pb(II) ions with vortex-assisted restricted access-based supramolecular solvent microextraction (RA/SUPRAS-LPME) method. The new complexing agent was characterized by a combination of elemental analyses, Proton Nuclear Magnetic Resonance (1H- NMR), Carbon-13 Nuclear Magnetic Resonance (13C NMR) and Fourier Transform Infrared spectroscopy (FT-IR) and techniques. Extraction of the complex which was formed at pH 8.0 was done by using a supramolecular solvent phase of tetrahydrofuran (THF) and 1-decanol. A microsampling flame atomic absorption spectrophotometer was used to measure the lead ion concentrations of the extract. The method optimized and the optimum experimental conditions were found as; pH = 8, amount of the ligand 2,25 mg, supramolecular solvent volume 50 µL, sample volume 20 mL and vortex time 3 min. The limit of detection (LOD), limit of quantification (LOQ) were calculated as 0.69 µg L-1 and 2.29 µg L-1, respectively. Linear range was found between 15.1 µg L-1 and 606 µg L-1. The developed method was applied to Pb(II) determination in real samples after evaluating the accuracy by using the TMDA-53.3 fortified environmental water sample as certified reference material.

Vortex-assisted magnetic solid phase extraction of Pb and Cu in some herb samples on magnetic multiwalled carbon nanotubes.

This study is the development of a new solid phase extraction method based on using magnetic multiwalled carbon nanotubes impregnated with 1-(2-pyridylazo)2-naphthol (PAN) for separation, preconcentration, and flame atomic absorption spectrometric determination of Pb(II) and Cu(II). Optimization of the method was done by investigating pH effect, amount of magnetic multiwalled carbon nanotubes impregnated with PAN, eluent type and volume, matrix effects, and volume of the sample. The optimum adsorbent amount was found to be 75 mg and the optimum pH value was found as 5.5. The detection limits were 16.6 µg L-1 for Pb(II) and 18.9 µg L-1 for Cu(II). The relative standard deviations (RSD%) were less than 4%. Two certified reference materials: SPS-WW2 wastewater and NCS-DC73349 (bush branches and leaves) were used to test the validation of the method. The method was successfully applied to the analysis of Pb(II) and Cu(II) ions in daisy, mint, paprika, sage, rosemary, daphne leaves, heather, green tea, andViburnum opulussamples.

Heavy metal contents of play dough, face and finger paint samples sold in turkish markets.

Lead, cadmium, nickel, manganese, cobalt and copper contents of some play dough, face and finger paint samples were determined by using a new solid phase extraction method which has been developed by using multi-walled carbon nanotube with patent blue (V) sodium salt to selectively separate and preconcentrate these metal ions. Flame atomic absorption spectrometry was used to determine the metal ions. Analytical parameters affecting the complex formation and solid phase extraction performance such as pH, the amount of ligand and volume of sample solution were investigated. The recoveries of the studied metal ions were not affected by the foreign ions. Analytes were recovered quantitatively at pH 5.5 and with a nitric acid of 2molL-1 as eluent. Analysis of a certified reference material was performed to validate the method before applying it to determine the metal ions in the real samples. Detection limits were found to be as Pb(II): 7.71µgL-1, Cu(II): 1.43µgL-1, Cd(III): 0.21µgL-1, Mn(II): 0.47µgL-1, Ni(II): 3.52µgL-1and Co(II): 1.96µgL-1.

Synthesis of urease hybrid nanoflowers and their enhanced catalytic properties.

Increasing numbers of materials have been extensively used as platforms for enzyme immobilization to enhance catalytic activity and stability. Although stability of enzyme was accomplished with immobilization approaches, activity of the most of the enzymes was declined after immobilization. Herein, we synthesize the flower shaped-hybrid nanomaterials called hybrid nanoflower (HNF) consisting of urease enzyme and copper ions (Cu(2+)) and report a mechanistic elucidation of enhancement in both activity and stability of the HNF. We demonstrated how experimental factors influence morphology of the HNF. We proved that the HNF (synthesized from 0.02mgmL(-1) urease in 10mM PBS (pH 7.4) at +4°C) exhibited the highest catalytic activity of ∼2000% and ∼4000% when stored at +4°C and RT, respectively compared to free urease. The highest stability was also achieved by this HNF by maintaining 96.3% and 90.28% of its initial activity within storage of 30 days at +4°C and RT, respectively. This dramatically enhanced activity is attributed to high surface area, nanoscale-entrapped urease and favorable urease conformation of the HNF. The exceptional catalytic activity and stability properties of HNF can be taken advantage of to use it in fields of biomedicine and chemistry.

Sea sponge as a low cost biosorbent for solid phase extraction of some heavy metal ions and determination by flame atomic absorption spectrometry.

A new, easy, sensitive, and environmentally friendly separation and preconcentration method was developed to determine Cu(ll), Fe(lll), Pb(ll), and Ni(ll) at trace levels by use of a column filled with sea sponge without any complexing reagent, and atomic absorption spectrometry. The influences of analytical parameters, such as pH of the solutions, type of eluent, volume of sample, solution and eluent flow rates, and diverse ions, were examined for the quantitative recoveries of the analyte ions. The metal ions were eluted from the column by using 2 M HNO3. Accurate results were found for spiked samples after applying the preconcentration method. The LOD values were found to be between 1.5 and 5.6 µg/L based on three times the SD of the blanks. The method has been successfully applied to determine Cu(ll), Fe(lll), Pb(ll), and Ni(ll) ions in tap water samples, mineral water samples, and a certified reference material.

Solid-phase extraction of some heavy metal ions on a double-walled carbon nanotube disk and determination by flame atomic absorption spectrometry.

A new preconcentration method was developed for the determination of trace amounts of Cu(II), Fe(III), Pb(II), Ni(II), and Cd(II) on a double-walled carbon nanotube disk. 4-(2-Thiazolylazo) resorcinol was used as a complexing reagent. The effects of parameters, including pH of the solutions, amounts of complexing reagent, eluent type, sample volume, flow rates of solutions, and matrix ions were examined for quantitative recoveries of the studied analyte ions. The retained metal ions were eluted by 2 M HNO3. The LOD values for the analytes were in the range of 0.7-4.4 microg/mL. Natural water samples and standard reference materials were analyzed by the presented method.

Selective preconcentration of thallium species as chloro and iodo complexes on Chromosorb 105 resin prior to electrothermal atomic absorption spectrometry.

A selective preconcentration method was described for the determination of inorganic thallium species by electrothermal atomic absorption spectrometry (ETAAS). Thallium(III) and thallium(I) as chloro and iodo complexes were selectively retained by a column containing 0.5 g of Chromosorb 105 resin and quantitatively eluted by 10 mL of pure acetone. The calibration graph was linear with a correlation coefficient of 0.997 at levels near the detection limit and up to at least 0.8 µg L(-1). The detection limits for the determination of total thallium and thallium(III) employing the proposed method by ETAAS were estimated as three values of the standard deviations, 0.050 µg L(-1) and 0.034 µg L(-1), respectively. Verification of the accuracy was carried out by the analysis of standard reference materials (GBW 07402 soil, NIST 2710 Montana soil, GBW 07309 and GBW 07310 stream sediments). The relative errors were found to be in the range of -7.7% to +4.8%. The relative standard deviations were generally found to be below 10%. The effect of potential interfering ions on the determination was studied. The proposed method was successfully applied to the determination of total thallium in five different brand cements, soils around two cement plants and metallic zinc samples. The speciation of thallium(I) and thallium(III) was applied to synthetic solutions.

Development of a coprecipitation system for the speciation/preconcentration of chromium in tap waters.

A method for the speciation of chromium(III), chromium(VI) and determination of total chromium based on coprecipitation of chromium(III) with dysprosium hydroxide has been investigated and applied to tap water samples. Chromium(III) was quantitatively recovered by the presented method, while the recovery values for chromium(VI) was below 10%. The influences of analytical parameters including amount of dysprosium(III), pH, centrifugation speed and sample volume for the quantitative precipitation were examined. No interferic effects were observed from alkali, earth alkali and some transition metals for the analyte ions. The detection limits (k=3, N=15) were 0.65 microg/L for chromium(III) and 0.78 microg/L for chromium(VI). The validation of the presented method was checked by the analysis of certified reference materials.