Octadecyl-bonded Silica Membrane Disks Research Articles

Flame Atomic Absorption Determination of Cd and Cu in Biological Samples After Solid Phase Extraction by Octadecyl Silica Membrane Disks Modified With a Schiff Base Ligand

A procedure for separation and preconcentration of trace amounts of Cu 2+ and Cd 2+ from aqueous media is proposed. The procedure is based on the adsorption of Cu 2+ and Cd 2+ ions on octadecyl bonded silica membrane disk modified with, Pyridine 2,6-diylbis{2,2’(azamethane-1-ylidene)4-bromophenol} ( L ) at pH = 8. The ligand has been synthesized by reaction of the 2,6-diamino pyridine and 5-bromo salicylaldehyde at ethanol under refluxing. The structure of the synthesized compound resulted from the Fourier-transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance ( 1 H NMR), Mass spectrometry ( MS ) and UV spectroscopy and elemental analysis data. The solid phase extraction experimental conditions were optimized by changing several parameters such as volume of eluting solvent, the effect of pH, limit of detection and maximum capacity of the disks for Cu 2+ and Cd 2+ recovery. The retained Cu 2+ and Cd 2+ ions were then stripped from the disk with a minimal amount of 0.7 mol.L -1 nitric acid and 1 mol.L -1 hydrochloric acid solution as eluent respectively, and determined by flame atomic absorption spectrometry. The limit of detection of the proposed method was 7.6 and 3.6 ng.mL -1 for copper and cadmium ions, respectively. The method was successfully applied to determination of copper and cadmium in natural biological samples and the method was quantitative. DOI: http://dx.doi.org/10.17807/orbital.v10i7.1111

Preconcentration of Trace Copper (II) Using octadecyl Silica Membrane Disks Modified Functionalized Graphene with Octadecylamine (ODA–GO) in Water and Paraffin-Embedded Tissues from Liver Loggerhead Turtles Specimens by FAAS

A simple and reproducible method for the rapid extraction and determination of trace amounts of copper (II) ions using octadecyl-bonded silica membrane disks modified by Functionalized Graphene with octadecylamine (ODA-GO) and Atomic Absorption Spectrometry is presented. The method is based on complex formation on the surface of the ENVI-18 DISK TM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effect of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about 1000mL providing a preconcentration factor of 500. In the present study, we report the application of preconcentration techniques still continues increasingly for trace metal determinations by flame atomic absorption spectrometry (FAAS) for quantification of Cu in Formalin-fixed paraffin-embedded (FFPE) tissues from Liver loggerhead turtles. The maximum capacity of the disks was found to be 389± 4 µg for Cu 2+ .The limit of detection of the proposed method is 3ng per 1000mL.The method was applied to the extraction and recovery of copper in different water samples.

Extraction of Trace Amounts Copper (II) Using Octadecyl Silica Membrane Disks Modified Isocyanate-Treated GOs (iGOs)

A number of functionalized graphite oxides were prepared by treatment of graphite oxide (GO) with organic isocyanates. A simple and reproducible method for the rapid extraction and determination of trace amounts of copper (II) ions using octadecyl-bonded silica membrane disks modified by isocyanate-treated GOs (iGOs) and Atomic Absorption Spectrometry is presented. The method is based on complex formation on the surface of the ENVI-18 DISK disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effect of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about 1000mL providing a preconcentration factor of 500. The maximum capacity of the disks was found to be 389± 4 μg for Cu.The limit of detection of the proposed method is 5ng per 1000mL.The method was applied to the extraction and recovery of copper in different water samples.

Preparation of a Modified Octadecyl Silica Membrane Disk for Solid Phase Extraction of Lead(II) Ions in Different Real Samples and their Determination with ICP-AES

A solid phase extraction and inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of lead(II) ions with octadecyl-bonded silica membrane disks modified by 4-methyl-N-{2-(4-methylbenzothioyl)aminoethyl}benzenecarbothioamide (MMAB) was studied. Extraction efficiency, and the effects of parameters such as flow rate, pH, type and the least amount of acid for stripping of lead(II) from the modified disks and break through volume were examined. The maximum capacity of the membrane disks modified by 4.0 mg of MMAB used was found to be 527 ± 4 µg of lead(II) ions. The preconcentration factor is 440 (for 2200 mL water sample and flow rate of 12 mL min-1) and detection limit of the proposed method is 85.4 ng mL-1. The developed method was successfully applied to the determination of lead(II) ions in blood, spinach, bean, hair, milk, pepper and various water samples.

Octadecyl-Bonded Silica Membrane Disk Modified with Cyanex302 for Pre-Concentration and Determination of Iron in Food Products

A simple and rapid method using an octadecyl-bonded silica membrane disk impregnated with Cyanex302 is described for the pre-concentration and determination of iron. The influence of various parameters on sorption and elution of Fe(III) were systematically investigated. The sorption of Fe(III) at pH 3.2 was quantitative (99.3 +/- 1.1%). It was completely recovered using 20 mL 5.0 M HCI and determined by flame atomic absorption spectrometry. Breakthrough volume of the modified disk for Fe(III) was >2000 mL, pre-concentration factor was >100, and reusability up to 28 cycles. The LOD and LOQ for Fe(III) were 0.45 microg/L and 1.51 microg/L, respectively, while precision for its determination in terms of RSD was < or =2.1%. This method was applied for Fe(III) determination in milk, fortified flour, cocoa powder, tea, and black pepper. To validate the procedure, EPA Method Standard (QC standard 21) was analyzed for Fe(III).

Octadecyl Bonded Silica Membrane Disk Modified with Cyanex302 for Preconcentration and Determination of Traces of Cobalt in Urine by Flame Atomic Absorption Spectrometry

Octadecyl bonded silica membrane disk was impregnated with Cyanex302 for flame atomic absorption spectrometric determination of traces of cobalt(II) in urine. The solid phase extraction method developed using the modified disk was systematically investigated for sorption-desorption of cobalt(II). Cobalt(II) was quantitatively sorbed on the disk at pH 6.0 and eluted using 15 cm3 of 1 × 10−3 M HCl. The lower limit of detection for cobalt(II) was 1.5 µg dm−3 and the preconcentration factor 133 with a precision in terms of relative standard deviation (% R. S. D.) 0.6. The reusability of the modified disk was ≥35 cycles.

Octadecyl bonded silica membrane disk modified with Cyanex302 for separation and flame atomic absorption spectrometric determination of nickel from tap water and industrial effluent

A simple and reliable method based upon impregnation of Cyanex302 on octadecyl bonded silica membrane disk has been developed for separation and atomic absorption spectrometric determination of nickel. The influence of various parameters like aqueous phase pH, flow rate and volume of eluent were investigated systematically to optimize the conditions for quantitative sorption and desorption of nickel. The break through volume for nickel was greater than 1.0 dm 3, enrichment factor more than 100 and a detection limit of 2.1 μg dm −3 was achieved. The method applied for detection of nickel in tap water and effluent sample had a relative standard deviation (R.S.D.) of 0.4%.

Solid phase extraction of zinc with octadecyl silica membrane disks modified by N,N’-disalicylidene-1,2-phenylendiamine and determination by flame atomic absorption spectrometry

A procedure for separation and preconcentration of trace amounts of Zn(II) from aqueous media is proposed. The procedure is based on the adsorption of Zn2+ on octadecyl bonded silica membrane disk modified with N,N’-disalicylidene-1,2-phenylendiamine at pH 7. The retained zinc ions were then stripped from the disk with a minimal amount of 1.5 mol L-1 hydrochloric acid solution as eluent, and determined by flame atomic absorption spectrometry. Maximum capacity of the membrane disk modified with 5 mg of the ligand was found to be 226 μg Zn2+. The relative standard deviation of zinc for ten replicate extraction of 10 μg zinc from 1000 mL samples was 1.2%. The limit of detection of the proposed method was 14 ng of Zn2+ per 1000 mL. The method was successfully applied to the determination of zinc in natural water samples and accuracy was examined by recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry (GFAAS).

2-Propylpiperidine-1-carbodithioate로 수식화한 Octadecyl 실리카 막으로 구리(II)의 예비농축 및 불꽃 원자흡수분광법으로의 정량

2-Propylpiperidine-1-carbodithioate(PPCD)I 로 수식화한 octadecyl로 결합된 실리카 막 디스크로 구리(II) 이온의 잔유양의 추출과 간단하고 빠르게 원자흡수분광법(AAS)으로의 정량법을 소개한다. 추출효율과 흐름속도, pH, 형 태, 벗김 산의 가장 적은 양에 대해 연구되었다. Anthraquinone 유도체의 2 mg로 수식한 막디스크의 최대 용량은 425 μg Cu2+ 이었다. 제안한 방법의 검출한계는 7 ng/ml이다. 이 방법은 다른 시료와 온천수 시료로부터 Cu2+의 회수에 적용하 였다. A simple and fast method for extraction and determination of trace amounts of copper(II) ions using octadecyl-bonded silica membrane disks modified with 2-propylpiperidine-1-carbodithioate (PPCD)I and atomic absorption spectrometry (AAS) is introduced. Extraction efficiency and the influence of flow rates, pH, and type and smallest amount of stripping acid were investigated. Maximum capacity of the membrane disks modified with 2 mg of the anthraquinone derivative used was found to be 425μg Cu2+. The limit of detection of the proposed method is 7 ng/ml. The method is applied to the recovery of Cu2+ from different synthetic samples and a spring water sample.

Preconcentration, speciation and determination of ultra trace amounts of mercury by modified octadecyl silica membrane disk/electron beam irradiation and cold vapor atomic absorption spectrometry

Mercury (II) and methyl mercury cations at the Sub-ppb level were adsorbed quantitatively from aqueous solution onto an octadecyl-bonded silica membrane disk modified by 2-[(2-mercaptophyenylimino)methyl] phenol (MPMP). The trapped mercury was then eluted with 3 ml ethanol and Hg 2+ ion was directly measured by cold vapor atomic absorption spectrometry, utilizing tin (II) chloride. Total mercury (Hgt) was determined after conversion of MeHg + into Hg 2+ ion by electron beam irradiation. A sample volume of 1500 ml resulted in a preconcentration factor of 500 and the precision for a sampling volume of 500 ml at a concentration of 2.5 μg l −1 ( n = 7) was 3.1%. The limit of detection of the proposed method is 3.8 ng l −1. The method was successfully applied to analysis of water samples, and the accuracy was assessed via recovery experiment.

Solid phase extraction of copper (II) by sorption on octadecyl silica membrane disk modified with a new Schiff base and determination with atomic absorption spectrometry

A simple, selective and reliable method for rapid extraction and determination of trace amounts of Cu (II) ions from aqueous samples using octadecyl-bonded silica membrane disks modified with bis-(3-methoxy salicylaldehyde)-1,6-diaminohexane and flame atomic absorption spectrometry (FAAS) is presented. Extraction efficiency, the influence of pH, flow rates, amount of ligand, and type and least amount of eluant were investigated. The linear dynamic range of the proposed method for Cu (II) ions was found in a wide concentration range of 1.0 (± 0.2)–150 (± 2) μg l − 1 . The detection limit and preconcentration factor of this method were found 30.0 (± 0.7) ng l − 1 and 100 respectively. The reproducibility of the procedure is at the most 2.0%. The effects of various cationic interferences on the percent recovery of copper ion were studied. The method was used to the recovery of copper ion from different synthetic, alloys and biological samples.

Solid phase extraction of zinc with octadecyl silica membrane disks modified by N,N'-disalicylidene-1,2-phenylendiamine and determination by flame atomic absorption spectrometry

A procedure for separation and preconcentration of trace amounts of Zn(II) from aqueous media is proposed. The procedure is based on the adsorption of Zn2+ on octadecyl bonded silica membrane disk modified with N,N’-disalicylidene-1,2-phenylendiamine at pH 7. The retained zinc ions were then stripped from the disk with a minimal amount of 1.5 mol L-1 hydrochloric acid solution as eluent, and determined by flame atomic absorption spectrometry. Maximum capacity of the membrane disk modified with 5 mg of the ligand was found to be 226 μg Zn2+. The relative standard deviation of zinc for ten replicate extraction of 10 μg zinc from 1000 mL samples was 1.2%. The limit of detection of the proposed method was 14 ng of Zn2+ per 1000 mL. The method was successfully applied to the determination of zinc in natural water samples and accuracy was examined by recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry (GFAAS).

Solid phase extraction and flame atomic absorption spectroscopic determination of trace amounts of iron(III) using octadecyl silica membrane disks modified with 2-mercaptopyridine-1-oxide

A simple and selective method for rapid extraction and determination of trace amounts of iron(III) using octadecyl-bonded silica membrane disks modified with 2-mercaptopyridine-1-oxide and flame atomic absorption spectroscopy is presented. The factors influencing extraction efficiency were evaluated, including the nature of the counter anion, pH of the sample solution, amount of ligand, flow rate of the sample and type of stripping solution. The maximum capacity of the membrane disk, modified by 10 mg of the ligand, was found to be 926 ± 6 μg of iron(III). The breakthrough volume was greater than 2500 ml. Iron(III) was completely recovered (>99%) from water with a preconcentration factor of more than 166. The limit of detection of the proposed method was 0.63 ng ml−1. The various cationic interferences had no effect on the recovery of iron(III) from the binary mixtures. The proposed method was applied to the determination of iron(III) from three different water samples.

Solid phase extraction of lead on octadecyl bonded silica membrane disk modified with Cyanex302 and determination by flame atomic absorption spectrometry

A simple, reliable and rapid method for preconcentration and determination of lead using octadecyl bonded silica membrane disk impregnated with Cyanex302 and flame atomic absorption spectrometry is presented. The influence of aqueous phase pH, type of eluent, flow rates of sample solution and eluent, volume of eluent and amount of extractant has been investigated. The break through volume is greater than 4.0 dm 3 with an enrichment factor of more than 400 and a detection limit of 1.0 μg dm −3. The method developed for determination of lead is good as six replicate determinations using 100 cm 3 solution containing lead in the range 1–4900 μg provides a relative standard deviation (R.S.D.) of 0.4%. The selectivity of the proposed method was confirmed from the interference studies. The developed procedure was successfully applied for the determination of lead in spiked sea water, USGS standard soil sample, sludge and industrial effluents, medicinal formulation, plant, some food products and wine.

Determination of nickel in natural waters by FAAS after sorption on octadecyl silica membrane disks modified with a recently synthesized Schiff’s base

A simple, highly sensitive, accurate and selective method for the determination of trace amounts of Ni 2+ ions in water samples is proposed. The method is based on the separation and preconcentration of Ni 2+ on an octadecyl-bonded silica (ODBS) membrane disk modified by a recently synthesized Schiff’s base N, N′-bis (3-methylsalicylidene) ortho phenylene diamine (MSOPD) at pH 7. The synthesis of this extractant ligand is also described. The retained nickel on the membrane was eluted with 2×5 ml 0.5 M HNO 3 and measured by flame atomic absorption spectrometry (FAAS) at 232.0 nm. The extraction efficiency and the influence of the type and least amount of eluent for the stripping of Ni 2+ from the disks, pH, flow rates of sample solution and eluent, amount of MSOPD, effect of other ions, and breakthrough volume were evaluated. The maximum capacity of the membrane disks modified by 3 mg of MSOPD was found to be 146±4 μg Ni 2+. The 3 σ limit of detection of the method was 30 ng per 1000 ml and also an enrichment factor of 250 was obtained. The proposed method has been applied to the determination of nickel in several water samples with satisfactory results.

Octadecyl silica membrane disks modified with a new Schiff's base for the preconcentration of lead and copper before their determination in water samples.

A simple and fast method for the extraction and determination of ppt level of Pb2+ and Cu2+ ions using octadecyl-bonded silica membrane disks modified by a new tetradentates Schiffs base [Bis(2,4-dimethoxy benzaldehyde) ethylen diimine](TDSB) and inductively coupled plasma atomic emission spectrometry is described. Extraction efficiency, and influence of flow rate, pH, type and the least amount of acid for stripping of Cu2+ and Pb2+ from the modified disks and break through volume were evaluated. The maximum capacity of the membrane disks modified by 5 mg of TDSB used was found to be 347 +/- 7 and 470 +/- 6 microg of copper and lead, respectively. The concentration factor is 500 (for 2500 mL water sample and flow rate of 20 mL min(-1)) and detection limit of the proposed method is 12.5 and 150.5 pg/ml for Cu2+ and Pb2+, respectively. The method was applied to the determination of Cu2+ and Pb2+ ions from various water, wastewater, black tea, and hot pepper samples.

Ultra-trace monitoring of copper in environmental and biological samples by inductively coupled plasma atomic emission spectrometry after separation and preconcentration by using octadecyl silica membrane disks modified by a new schiff's base

Ultra-trace amounts of Cu(II) were separated and preconcentrated by solid phase extraction on octadecyl-bonded silica membrane disks modified with a new Schiff,s base (Bis- (2-Hydroxyacetophenone) -2,2-dimethyl-1,3-propanediimine) (SBTD) followed by elution and inductively coupled plasma atomic emission spectrometric detection. The method was applied as a separation and detection method for copper(II) in environmental and biological samples. Extraction efficiency and the influence of sample matrix, flow rate, pH, and type and minimum amount of stripping acid were investigated. The concentration factor and detection limit of the proposed method are 500 and 12.5 pg mL-1, respectively.

Ultratrace determination of lead, cadmium and copper in environmental and biological samples by atomic absorption spectrometry after their separation and preconcentration using octadecyl silica membrane disks modified with a new n–s schiff base

Pb(II), Cd(II) and Cu(II) ions were separated and preconcentrated by solid-phase extraction on octadecyl-bonded silica membrane disks modified with a new S–N-containing Schiff base (bis-2-thiophenal propandiamine) (BTPD) followed by elution and atomic absorption spectrometric detection. The method was applied as a separation and detection method for lead(II), cadmium(II) and copper(II) in environmental and biological samples. Extraction efficiency and the influence of sample matrix, flow rate, pH, and type and minimum amount of stripping acid were investigated. The maximum capacity of the membrane disks modified by 4 mg of BTPD was found to be 668 ± 10, 480 ± 8 and 454 ± 7 µg of lead, cadmium and copper, respectively. The limit of detection of the proposed method is 0.25, 0.01 and 0.02 ng/mL for lead, cadmium and copper, respectively.

Solid-phase extraction-spectrophotometric determination of uranium(VI) in natural waters.

A method for the extraction and determination of uranyl ion in natural waters using octadecyl bonded silica membrane disks modified with piroxicam and spectrophotometry with arsenazo(III) is proposed. The perconcentration step was studied with regard to experimental parameters such as amount of extractant, type and amount of eluent, pH, flow rates and tolerance limit of diverse ions on the recovery of uranyl ion. The limit of detection of the proposed method is 0.4 micro g L(-1) of uranyl. The method was applied to the recovery of uranyl from different water samples.

Separation and Preconcentration of Palladium(II) on Octadecyl-Silica Membrane Disks

A simple and selective method for rapid extraction and determination of Pd(II) ions was developed based on sorption on octadecyl-bonded silica membrane disks of an ion associate of PdBr42− anion with 1-hexadecylpyridinium cation. The sample containing Pd(II) in the presence of 0.15 M of NaBr and 10 mg 1-hexadecylpyridinium bromide was passed through the membrane disk by applying a slight vacuum. Elution was accomplished using 6 ml of acetonitrile. Extraction efficiency and the influence of flow rates of sample solution and eluent, pH, amount of 1-hexadecylpyridinium bromide, type and least amount of eluent for elution of Pd(II) from disks, break through volume and limit of detection were evaluated. Also the effect of various ions on percent recovery of Pd(II) was studied. Extraction efficiencies > 99% were obtained by elution of the disks with minimal amount of solvent. The extraction efficiencies do not depend on the pH (1–10) of solutions nor on the sample solution flow rate in the range of 1–25 ml/min. Hence, with a typical preconcentration factor of 200 the limit of detection of the proposed method is 0.6 µg (for 1000 ml of sample solution). The method was applied to the recovery and determination of Pd(II) in Al–Si–Pd catalysts.