Solid Phase Extraction and Simultaneous Spectrophotometric Determination of Trace Amounts of Copper and Iron Using Mixture of Ligands

 A novel sensitive and simple method for rapid and selective extraction, preconcentration and determination of iron (as its bathophenanthroline complex) and copper (as its neocuproine complex) using octadecyl silica cartridges and dual wavelength spectrophotometry is presented. The dual wavelength method (533 nm for the iron-bathophenanthroline and 454 nm for the copper-neocuproine as the analytical wavelength) is used to eliminate spectral interferences. Extraction efficiency and the influence of flow rates of sample solution and eluent, pH, amount of neocuproine, bathophenanthroline and hydroxylamine hydrochloride, type and least amount of eluent for elution of iron and copper complexes from cartridge, break-through volume and limit of detection are evaluated. The effects of various cationic and anionic interferences on percent recovery of iron and copper are also studied. Extraction efficiencies >95% are obtained by elution of cartridges with minimal amount of organic solvent. Iron and copper were determined in the range of 3–100 ng mL⁻¹. The limits of detection are 0.98 and 1.13 ng mL⁻¹ for iron and copper, respectively. The proposed method is applied successfully to the determination of both analytes in river, tap and well water samples. Author for correspondence. E-mail: yyamini@modares.ac.ir Received September 18, 2002; accepted December 12, 2002 Published online May 5, 2003     

Determination of Iron in Calf Serum Using Bathophenanthroline and Thermal Lens Spectrometry

ABSTRACT

Thermal lens spectrometry has been used for the determination of iron in calf serum. The method is based on dissociation of Fe³⁺ from proteins, reduction of Fe³⁺ to Fe²⁺ and formation of a coloured complex between Fe²⁺ and bathophenanthroline. Contrary to the spectrophotometric method, it is shown that thermal lens spectrometry is less sensitive to scattering caused by the presence of small particles remaining in the test solution after the deproteinization step. The background signal is very small and the response is only slightly dependent on the amount of scattering particles. The method is reliable, sensitive and reproducible. The limit of detection for iron is 4 ppb and the relative standard deviation is around 2%. It is expected that the volume of serum sample necessary for an analysis can be reduced to less than 100 μl.     

Performance improvement of MEH-PPV:PCBM solar cells using bathocuproine and bathophenanthroline as the buffer layers

In this work, bathocuproine (BCP) and bathophenanthroline (Bphen), commonly used in small-molecule organic solar cells (OSCs), are adopted as the buffer layers to improve the performance of the polymer solar cells (PSCs) based on poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV): [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction. By inserting BCP or Bphen between the active layer and the top cathode, all the performance parameters are dramatically improved. The power conversion efficiency is increased by about 70% and 120% with 5-nm BCP and 12-nm Bphen layers, respectively, when compared with that of the devices without any buffer layer. The performance enhancement is attributed to BCP or Bphen (i) increasing the optical field, and hence the absorption in the active layer, (ii) effectively blocking the excitons generated in MEH-PPV from quenching at organic/aluminum (Al) interface due to the large band-gap of BCP or Bphen, which results in a significant reduction in series resistance (Rs), and (iii) preventing damage to the active layer during the metal deposition. Compared with the traditional device using LiF as the buffer layer, the BCP-based devices show a comparable efficiency, while the Bphen-based devices show a much larger efficiency. This is due to the higher electron mobility in Bphen than that in BCP, which facilitates the electron transport and extraction through the buffer layer to the cathode.     

Perchlorate Ion-Selective Electrodes with the Liquid Membranes of the O-Phenanthroline Chelate or its Related Compounds

Abstract

The metal chelates of o-phenanthroline, a, a′-dipyridyl or bathophenanthroline were used as the ion exchanger in the liquid membrane of the perchlorate ion-selective electrode. The electrode with a nitrobenzene membrane containing tris(bathophenanthroline)ferrous perchlorate is the highest sensitive one and gives a linear Nernstian response up to about 1 × 10 ^?5 M perchlorate. The membrane electrode having the ferrous ion-chelate of o-phenanthroline as an ion exchanger shows an excellent selectivity for perchlorate ion over nitrate or iodide Ion. The effects of the chelate concentration in the membrane and the central metal species of the chelate are examined on the electrode performance.     

Membrane sensors for batch and flow injection potentiometric determination of ethamsylate (cyclonamine) in pharmaceutical preparations

The lipophilic nickel(II) and iron(II) bathophenanthroline derivatives of ethamsylate are used as ion-exchangers with high selectivity characteristics for ethamsylate. Poly(vinyl chloride) membrane sensors incorporating these electroactive materials display fast linear response for 1 × 10^–1–1 × 10^–4 M ethamsylate under static and hydrodynamic modes of operation. In an acetate buffer of pH 4, the calibration slope is 51–53 mV/concentration decade and the lower limit of detection is 5.3 g/ml. Except for salicylate and nitrate, most common anions, organic sulfonates, carboxylates, phenolates and various pharmaceutical excipients and diluents do not interfere. Determination of ethamsylate in various dosage forms shows an average recovery of 98.9% of the nominal and a mean standard deviation of 0.7%.     

A novel planar miniaturized potentiometric sensor for flow injection analysis of nitrates in wastewaters, fertilizers and pharmaceuticals

A novel all-solid-state miniaturized nitrate sensor is developed, characterized and used for flow injection analysis (FIA) of nitrates in various samples. The sensor incorporates silver bis(bathophenanthroline) nitrate [Ag(bath)₂NO₃] as an electroactive material in a plasticized PVC membrane. The sensing membrane (3 mm × 5 mm) is immobilized on a wafer polyimide microchip (size 13.5 mm × 3.5 mm) to offer a planar miniaturized design easily used in a single channel wall-jet flow injection system. Under hydrodynamic mode of operation (FIA) the sensor displays fast response, high sensitivity, long term stability and good selectivity for NO₃⁻ in the presence of many common associated anions. The calibration slope is 55.1 ± 0.1 mV decade⁻¹ over the concentration range 1.0 × 10⁻¹ to 1.0 × 10⁻⁶ mol L⁻¹, the lower detection limit is 0.05 μg mL⁻¹, the working pH is 2-9,and the output is 70-90 samples h⁻¹. Validation of the assay method reveals good performance characteristics and suggests application for routine determination of NO₃⁻ in industrial wastewaters, fertilizers and pharmaceuticals. The results agree fairly well with data obtained by the standard spectrophotometric methods.     

NMR study on iridium(III) complexes for identifying disulfonate substituted bathophenanthroline regio-isomers

A series of novel biscyclometalated iridium (III) complexes with an ancillary disulfonated bathophenanthroline (DSBP(2-)) ligand, Ir(L)(2)DSBPNa, L = 2-phenylpyridine (ppy), 2,4-difluorophenylpyridine (fppy), and 1-phenylisoquinoline (piq) were found to have two isomeric forms. The chemical structures of the isomers were determined by the one- and two-dimensional (1)H and (13)C NMR studies. The isomeric state was proved to have originated from the disulfonate-related regio-isomer of the DSBP(2-) ligand.     

钒（Ⅴ）—向红菲咯啉的络合吸附波

在ＰＨ４．０２的０．０２ｍｏｌ／ＬＨＡｃ－ＮａＡｃ介质中，研究了钒（Ⅴ）向红菲咯啉（ＢＰＴ）的极谱行为。钒（Ⅴ）－ＢＰＴ络合物在滴汞电采上于－０．３６Ｖ得到一良好的吸附还原波，在聚乙烯醇（ＰＶＡ）存在下，其二阶导数值一钒（Ⅴ）浓度在５．０×１０６－８－４．０×１０＾－６ｍｏｌ／Ｌ范围内呈线性关系；检出限可达９．０×１０＾－９ｍｏｌ／Ｌ。应用该法测定饮用水及碳素钢中微量钒，结果较好讨论了ＰＶＡ的影响     

钼(Ⅵ)-向红菲啰啉络合物的吸附伏安行为

在 PH=4．0的 0．3 mol/L的 HAc－NaAc介质中，钼（Ⅵ）-向红菲啰啉体系在悬汞电极上，于-0．58 V（vs．SCE）电位处得到钼（Ⅵ）-向红菲啰啉络合物的吸附还原波，其1.5次微分伏安图的峰峰值epp与Mo（Ⅵ）在3．0X10-10”～1．2X10-7mol／L浓度范围内呈良好的线性关系，检测限可达8×10-11mol／LMo（Ⅵ）．方法用于豆类样品中微量钼的测定，结果较好。     

锑(Ⅲ)-向红菲咯啉络合吸附波及其应用

在 ０．０２ ｍｏｌ／Ｌ酒石酸（Ｃ４Ｈ６Ｏ６）－０．００３％溴化十六烷基三甲基铵（ＣＴＭＡＢ）介质中，研究了锑（Ⅲ）－向红菲咯啉（ＢＰＴ）的极谱行为。Ｓｂ（Ⅲ）－ＢＰＴ络合物在滴汞电极上于－０．５８ ｖ（ｖｓ．ＳＣＥ）得到一良好的吸附还原波，其二阶导数值与锑（Ⅲ）浓度在１×１０－８～７×１０－６ｍｏｌ／Ｌ范围内呈线性关系，检测下限可达８Ｘ１０－９ｍｏｌ／Ｌ。应用该法测定纯锡及铜合金中微量锑，结果较好。对电极反应机理进行了探讨。