Preconcentration of copper with the ion-pair of 1,10- phenanthroline and tetraphenylborate on naphthalene

A solid ion-pair material produced from 1,10-phenanthroline and tetraphenylborate on naphthalene provides a simple, rapid and fairly selective means of preconcentrating copper from up to 1000 ml of aqueous samples (about 200-fold concentration is possible). Copper is quantitatively adsorbed in the pH range 1.6–10.4 at a flow rate of 3 ml min^?1. The solid mass (0.2 g) is dissolved from the column with 5 ml of dimethylformamide (DMF) and copper is measured by atomic absorption spectrometry at 324.7 nm. Linear calibration is obtained for 2–28 μg of copper in 5 ml of DMF solution. Replicate determination of 14 μg of copper gave a mean absorbance of 0.220 (n = 7) with a relative standard deviation of 1.5%. The sensitivity for 1% absorption was 0.093 μg ml^?1. After optimization, the method was applied to determine trace copper in standard reference materials, natural waters, beverages and hair.     

Fabrication and characterization of a α,β,γ,δ-Tetrakis(1-methylpyridinium-4-yl)porphine/silica nanocomposite thin-layer membrane for detection of ppb-level heavy metal ions

A new detection membrane for filtration enrichment combined with colorimetric determination of Cd(II), Zn(II), Pb(II) and Cu(II) ions is presented. We have demonstrated the use of a dye nanoparticle coated test strip (DNTS) structured with a reagent layer for on-site analysis of trace metal ions. In this study, a [TMPyP/SA] DNTS coated with a nanocomposite layer (average thickness: 5.39 μm) of α,β,γ,δ-Tetrakis(1-methylpyridinium-4-yl)porphine (TMPyP) and silica-SA on the top surface of a cellulose ester membrane filter was fabricated by a simple filtration of an aqueous TMPyP/silica-SA nanocomposite dispersion through a membrane filter. The nanocomposite formation of cationic TMPyP and negatively charged colloidal SA (9–80 nm) was based on electrostatic interaction and was confirmed in the 120–800 nm diameter range by a dynamic light scattering photometer (DLS). To optimize the DNTS nanocomposite layer, surface uniformity, mechanical strength, the percent retention of TMPyP, and sensitivity to Cd(II) detection for six DNTSs with five different types of silica were examined. A half[TMPyP/SA] DNTS with an average layer thickness of 2.60 μm, which was prepared by controlling the amount of TMPyP and SA, demonstrated the highest sensitivity to Cd(II) ion because it had the lowest background absorbance. In addition, factors that affected the percent retention of TMPyP, such as pH and TMPyP/SA ratio, were determined. More than 99% of the TMPyP was retained on a membrane filter at pH 7.8 with a TMPyP and SA concentration of 2 × 10⁻⁵ M and 4 × 10⁻⁵ wt%, respectively. Filtration enrichment of 100 mL of an aqueous solution containing Cd(II), Zn(II), and Pb(II) at ppb levels was achieved by concentrating the metal ions in a nanocomposite layer (the effective TMPyP area was 1.77 cm², pH 10.2). The signaling surface changed from a brown color to green when the ions were captured. The percent extraction for metal ions on a half[TMPyP/SA] DNTS were estimated by TLC scanning and ICP-MS. It was observed that, when using the half[TMPyP/SA] DNTS, Cd(II) concentrations as low as 1 ppb were detectable at a filtration rate of 4.0–5.0 mL min⁻¹.     

Preconcentration of copper,lead, cadmium and zinc ions from water with 2-mercaptobenzothiazole loaded on glass beads with the aid of collodion

2-Mercaptobenzothiazole (MBT) loaded on glass beads with the aid of collodion was prepared and used for selective preconcentration of μg l^?1 levels of copper(II) and lead from aqueous solutions. Copper and lead were quantitatively retained on the loaded beads from solutions of pH 5.0–6.0 and >5.0, respectively, while cadmium(II) and zinc(II) were retained at ? pH 6.0 and 7.0, respectively. The retention capacity of the loaded beads was ca. 108 μg Cu g^?1 (1.7 μmol g^?1) at pH 5.5 for beads of 0.3–0.4 mm diameter. The mole ratios of MBT to copper(II) and lead(II) were ca. 10 and 45, respectively, regardless of the amount of MBT loaded on the beads. Copper was completely retained on the column at a high flow rate (21.7 ml min^? cm^?2) and lead(II) at up to 12.7 ml min^? cm^?2. Cadmium(II) and zinc(II) were not retained quantitatively even at low flow rates (< 1.2 ml min^?1 cm^?2). Thus, selective preconcentration of copper and lead was achieved by passing the sample through the column at high flow rate at pH 6.5. The copper and lead retained on the column were complete eluted together with the collodion with 5 ml of MIBK by batch-mode elution, and determined directly by one-drop atomic absorption spectrometry. Copper(II) and lead(II) in several kinds of water were determined.     

A flow injection system with ion-exchange for spectrophotometric determination of copper in rocks

A flow injection system is proposed for the spectrophotometric determination of copper in rocks. Samples are mineralized by treatment with hydrofluoric and perchloric acids and the solutions analysed after iron III precipitation. Copper is preconcentrated in a small CHELEX-100 resin column placed in the flow system, eluted with 2.5M nitric acid and further mixed with diethanoldithiocarbamate (DEDC) in basic medium. The coloured complex was monitored at 410 nm. With the proposed system, about 2-30 samples are run per hour with low reagent consumption. Beer's law is followed within 0.04 and 2.00, microg/ml. Precision and accuracy were assessed by using reference rock standards from USGS and GSJ with copper content as low as 0.4 microg/g with good precision and accuracy.     

A chemiluminescence method for the detection of electrochemically generated H2O2 and ferryl porphyrin

Electrochemical formation of H2O2 and the subsequent ferryl porphyrin were examined by measuring luminol chemiluminescence and absorption spectrum using flow-injection method. Emission was observed under the cathodic potential (0.05 V at pH 2.0 and -0.3 V at pH 11.0) by the electrochemical reduction of buffer electrolytes solution but no emission was observed at anodic potentials. Fe(III)TMPyP solution was added at the down stream of the working electrode and was essential for the emission. Removal of dissolved O2 resulted in the decrease of emission intensity by more than 70%. In order to examine the lifetime of reduced active species, delay tubes were used in between working electrode and Fe(III)TMPyP inlet. Experimental results suggested the active species were stable for quite long. The emission was quenched considerably (>90%) when hydroperoxy catalase was added at the down stream of the working electrode whereas SOD had little effect. Significant inhibition of the emission by the addition of alkene at the down stream of the Fe(III)TMPyP inlet was considered as evidence of oxo-ferryl formation. The spectra at reduction potential under aerated condition were shifted to the longer wavelength (>430 nm) compared to the original spectrum of Fe(III)TMPyP (422 nm). All the spectra were perfectly reproduced by a combination of Fe(III)TMPyP and O=Fe(IV)TMPyP (438 nm) spectra. These observations lead to the conclusion that H2O2 was produced first by electrochemical reduction of O2, which then converted Fe(III)TMPyP into O=Fe(IV)TMPyP to activate luminol. The current efficiencies for the formation of H2O2 were estimated as about 30-65% in all over the pH.     

Study on spectroscopic characterization of Pd porphyrin and its interaction with ctDNA

The fluorescence and solid substrate room temperature phosphorescence (SS-RTP) properties of Pd(II) meso-tetrakis (4-N-methyl-pyridiniumyl) porphyrin (Pd(II)TMPyP) were studied. The factors influencing the SS-RTP emission, such as filter type, inorganic salt sort, drying temperature, pre-drying time and drying time were investigated in detail. Strong SS-RTP signal can be induced on the slow speed filter paper in the presence of the external inorganic salt, Ca(NO₃)₂, with the maximum excitation and emission wavelengths at 421 nm and 675 nm, respectively. The interaction between calf thymus DNA (ctDNA) and Pd(II)TMPyP was investigated at pH 7.2 using SS-RTP, fluorescence and UV-vis spectroscopy. The SS-RTP intensity of Pd(II)TMPyP was enhanced efficiently with the increasing amount of ctDNA. This phenomenon demonstrates that the intercalated porphyrin is shielded by ctDNA to avoid collision quenching. This result was supported by SS-RTP lifetime measurement, SS-RTP anion quenching experiment and fluorescence polarization measurement. Furthermore, with the addition of ctDNA, the UV-vis spectra of Pd(II)TMPyP shows apparent hypochromicity (40%) at the Soret maximum of 417 nm and a red shift of Δλ = 15 nm, also indicating that Pd(II)TMPyP intercalates into ctDNA bases. The binding constant of Pd(II)TMPyP to ctDNA was calculated to be 4.41 × 10⁵ L/mol based on the derivative McGhee-von Hippel plots.     

Design of a dual-signaling sensing system for fluorescent ratiometric detection of Al3+ ion based on the inner-filter effect

A dual-signal sensing system based on the inner-filter effect (IFE) was demonstrated, in which the combination of two signaling mechanisms allows metal binding to turn on two fluorescence emission bands, independently. A proof-of-concept fluorescent ratiometric assay for Al(3+) in pure aqueous solution is presented. The proposed assay is based on the Al(3+)-induced color and fluorescence changes of Alizarin red S (ARS) and IFE between ARS and meso-tetra(N-methyl-4-pyridyl)porphine tetratosylate salt (TMPyP). In the absence of Al(3+), the absorption spectrum of the ARS in 0.2 M HAc-NaAc buffer (pH 5.5) has a strong peak at 420 nm, significantly overlapping with the excitation of TMPyP. ARS is expected to be capable of functioning as a powerful absorber to tune the emission of TMPyP on account of the spectral overlap. Binding of Al(3+) with ARS forms a fluorometric ARS/Al(3+) complex and shifts the maximum absorbance from 420 nm to 480 nm, which overlaps negligibly with the excitation of TMPyP and turns on the proper emission spectrum for TMPyP. Under the optimum conditions, The fluorescence intensity ratio, F(585)/F(651), responds to Al(3+) over a dynamic range of 0.1-1.5 μM, with a limit of detection of 40 nM, where F(585) and F(651) are the fluorescence intensity at 585 nm and 651 nm in the absence or presence of Al(3+), respectively. Further application in Al(3+)-spiked water samples suggested a recovery between 95 and 108%. The fluorescence response is highly selective for Al(3+) over other metal ions with the addition of thiourea as the masking agent.     

Column Chromatographic Preconcentration of Copper in Alloys and Complex Materials Using 9,10 Phenanthrenequinone Monoxime Supported on Naphthalene

Abstract

A solid chelating compound phenanthrenequinone monoxime PQM) supported on naphthalene provides a rapid and economical means of preconcentration and separation of copper from the aqueous samples. Copper forms a complex with PC:: supported on naphthalene in the column at pH 6.1–8.4 with a flow rate of 1 ml/min. The metal complex and naphthalene are dissolved out from the column with 5 ml of DMF and the absorbance is measured at 470 nm against reacent blank. Beer's law is obeyed in the concentration range 0.6 9.6 μg of copper in 5 ml of DMF. The molar absorptivity and sensitivity are 6.3×10⁴ L mol^?1 cm^?1 and 0.001 μg cm^?2 respectively.     

基于内滤效应的信号增强型诺氟沙星荧光分析法

基于茜素红和卟啉之间的荧光内滤效应,成功构建了一种分子识别事件与信号报告空间分离的、高选择性的荧光增强型诺氟沙星分析方法。结果表明,无诺氟沙星时,茜素红在420 nm处有最大吸收,这和卟啉的最大激发波长有较大重叠,茜素红和卟啉之间因发生内滤效应导致卟啉的荧光被有效猝灭;而茜素红与诺氟沙星的配合物在523 nm处有最大吸收,和卟啉的最大激发波长不再重叠,即诺氟沙星与茜素红之间的荷移反应破坏了该内滤效应,导致卟啉荧光恢复,据此,可将茜素红的吸收信号转变为高灵敏的卟啉的荧光信号。在最佳实验条件下,诺氟沙星的质量浓度在10 ~ 450 mg?L-1范围内与体系的相对荧光强度(IF/I0F)呈线性关系(r2=0.987 8),检出限(S/N=3)为5 mg?L-1。方法选择性好,常见金属离子和药物辅料不干扰诺氟沙星的测定。该研究利用内滤效应,将灵敏度较低的诺氟沙星紫外可见分析法转换为灵敏度较高的荧光分析法,且无需将分子识别单元和信号转导单元共价连接,无需复杂的荧光探针合成工艺,为设计该类药物的荧光分析法提供了新思路。     

Adsorptive voltammetric determination of copper with a benzoin oxime graphite paste electrode

A method for the determination of trace amounts of copper with a chemically modified carbon press-formed electrode is described. Copper could be accumulated at the electrode by complexing with benzoin oxime in ammonia buffer, then reduced at a constant potential of −0.4 V (vs. SCE) in nitric acid solution. Finally, a well-defined stripping peak could be obtained by scanning the potential in a positive direction. The response depends on the concentration of copper and accumulation time. For an accumulation time of 5 min the detection limit is about 1 ng/ml and the linear range is from 2 ng/ml to 4000 ng/ml, with a relative standard deviation of 5%. Many common metal ions have little or no effect on the determination of copper. The recommended procedure was applied to the determination of trace amounts of copper in natural water, and the results are in agreement with those of atomic-absorption spectrometry.     

Understanding droplet bridging in ionic liquid-based Pickering emulsions

Copper nanoparticles are prepared in aqueous solution by reducing copper ions with hydrazine hydrate in the presence of cetyl trimethylammonium bromide (CTAB) and polyvinylpyrrolydone (PVP) as stabilizers. With only CTAB was used as stabilizer, copper nanoparticles are aggregated and partially oxidized to Cu(2)O. When both PVP and CTAB were used, dispersed copper nanoparticles with 56 nm diameter were obtained. Copper nanoparticles are simply mixed with poly (3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) in aqueous solution to form conducting composite. The effect of copper weight percent and surfactants on the conductivity and stability of the composite has been investigated.     

SLS存在下meso 四(对三甲胺基苯基)卟啉测定微量铜

研究了表面活性剂十二烷基苯磺酸钠（ＳＬＳ） 存在时,ｍｅｓｏ 四（ 对三甲胺基苯基） 卟啉［Ｔ（４ ＴＭＡＰ）Ｐ］ 与铜的显色反应。在ｐＨ＝ ３ ．７ 的ＨＡｃ ＮａＡｃ 介质中,在ＳＬＳ存在下,铜与［Ｔ（４ ＴＭＡＰ）Ｐ］ 形成１∶２ 的稳定配合物,至少在４ ．５ｈ 内吸光度无变化。最大吸收波长位于４１０ｎｍ ,ε＝ ３ ．７９ ×１０５Ｌ·ｍｏｌ－ １·ｃｍ － １ 。铜在０ ～１ ．４０μｇ／２５ｍＬ内有良好线性关系。用于自来水及湖水中铜的测定,相对标准偏差小于３ ％ ,加标回收率在９８ ％ ～１０３％ 之间     

Extraction and spectrophotometric determination of nickel with 2-hydroxyacetophenone oxime and simultaneous determination of copper and nickel

It is observed that 2-hydroxyacetophenone oxime can be used for the quantitative extraction of nickel in the pH range 6.6-7.8 into methyl isobutyl ketone. The organic layer shows maximum absorbance at 375 nm. Beer's law is obeyed over the range 1-6 ppm. The colour of the organic layer is stable for more than 48 hr. Interferences have been studied and methods are suggested for their elimination. Copper and nickel are both quantitatively extracted at pH 7 and can be determined simultaneously and accurately in the range 1-6 microg/ml for copper and 1-4 microg/ml for nickel.     

DNA Damage and Apoptosis Induced by Photosensitization of 5,10,15,20-Tetrakis (N-methyl-4-pyridyl)-21H,23H-porphyrin via Singlet Oxygen Generation

Cancer photodynamic therapy (PDT) requires photosensitizers that efficiently and selectively destroy tumor cells. We investigated 5,10,15,20-tetrakis ( N -methyl-4-pyridyl)-21 H ,23 H -porphyrin (TMPyP) as a potential cancer treatment. Confocal fluorescence microscopy showed that TMPyP was localized in the nuclei, whereas 5-aminolevulinic acid (ALA)-derived protoporphyrin IX (PPIX) was localized diffusely in the cytoplasm of human leukemia (HL-60) cells. In HL-60 cells under UVA irradiation, TMPyP effectively induced apoptosis. Moreover, 8-oxo-7,8-dihydro-2'-deoxyguanosine, an oxidative product of 2'-deoxyguanosine, was accumulated in the DNA of cells treated with photoirradiated TMPyP, whereas only small amounts were observed in ALA-treated cells in the presence of UVA light. TMPyP and UVA caused extensive damage at every guanine residue in DNA fragments obtained from the human p 53 tumor suppressor gene and the c-Ha- ras -1 proto-oncogene, whereas PPIX induced little DNA damage under these conditions. Electron spin resonance spectroscopy using a singlet oxygen (¹O₂) probe and D₂O showed that photoexcited TMPyP generated ¹O₂. These results suggest that photoexcited TMPyP reacts with oxygen to generate ¹O₂, which in turn, oxidizes guanine residues. Taken together, the results demonstrated that TMPyP was localized in the nucleus where it was photosensitized to induce DNA damage, suggesting that TMPyP may have clinical utility as a nucleus-targeted PDT.     

Benzothiazole-2-aldehyde-2-quinolylhydrazone as a reagent for the extractive spectrophotometric determination of copper (II)

Benzothiazole-2-aldehyde-2-quinolylhydrazone (BTAQH) was used for the spectrophotometric determination of trace amounts of copper(II) after the extraction process. Copper(II) reacts with BTAQH at pH 8.3–12.6 to form a water-insoluble 1:2 complex, which can be extracted with many kinds of organic solvent. The extracted species with benzene has an absorption maximum at 523 nm and obeyed Beer's law over the range 0.09 to 0.75 ppm of copper. The molar absorptivity is 7.50 × 10⁴M^?1 cm^?1 at 523 nm. The spectral properties of the copper(II) complexes with some tridentate hydrazones containing benzothiazole ring as a functional group were also discussed.     

A Simplified Nitroso-R Salt-Based Optic Fiber Sensor for Copper

Copper (II) has been measured using a reflection-based optic fiber sensor associated with flow-injection analysis. The sensing layer consists of Nitroso-R salt immobilized on Amberlyst A-27 resin. The sensor responses linearly in the copper concentration range 0.01-1.0 μg/ml with a detection limit of 5.0 ng/ml. The relative standard deviation of seven measurements of 0.5 μg/ml copper was 6.0%. The sensor was not fully reversible but can be fully regenerated by using 1.0 M hydrochloric acid after each measurement.     

Stabilization of copper nanoparticles prepared by reduction from solutions of poly(acrylic acid) complexes with Cu2+ ions and poly(ethylene glycols)

Copper sols are prepared via the reduction of copper ions with hydrazine borane in dilute aqueous solutions of mixtures of the PAA-Cu²⁺ complex and poly(ethylene glycols) of various molecular masses at PEG: PAA = 0.25 base-mol/base-mol and PAA: Cu²⁺ = 10 base-mol/mol in the pH range 4.0–7.0. The stability of sols against oxidation (dissolution) or aggregation (enlargement) of metal nanoparticles is much higher than that of sols prepared in the absence of PEG. With an increase in the initial pH or a decrease in the molecular mass of PEG, the formed copper nanoparticles are much larger (no less than 20 nm in diameter) than copper nanoparticles occurring in the sol prepared in a solution of the PAA double complex with Cu²⁺ ions and high-molecular-mass PEG at a low initial pH (3–10 nm in diameter). Copper nanoparticles in sols prepared in solutions of complexes based on the high-molecular-mass PEG do not aggregate during exposure, thereby indicating the high stability of polymer screens on their surfaces.     

Differential pulse adsorption stripping voltammetric determination of copper(II) with 2-mercaptobenzimidazol at a hanging mercury-drop electrode.

Copper(II) was selectively accumulated on a hanging mercury-drop electrode by using 2-mercaptobenzimidazole. Ensuing measurements were carried out by differential pulse adsorption stripping voltammetry. Factors affecting the accumulation, reduction, and stripping steps were investigated and a procedure was developed. The optimum conditions for the analysis of copper were pH 5.0, 5.33 x 10(-5) M 2-mercaptobenzimidazole and an accumulation potential of -0.10 V (vs. Av/AgCl). A linear range was obtained in the concentration range 0.2-100 ng/ml with a 90 s accumulation time and a scan rate of 16 mV/s. For ten successive determinations of 1.0, 20.0 and 70.0 ng/ml copper(II), relative standard deviations of 4.2, 3.5 and 2.8%, respectively, were obtained. The developed method was applied to the determination of copper in commercial salts and aluminium alloys.     

Chromatographic preconcentration of copper in environmental and biological samples using 2,4,6-tri(2-pyridyl)-1,3,5-triazine-tetraphenylborate-naphthalene adsorbent

A method was established for the determination of trace amounts of copper using chromatographic preconcentration of copper(I) with 2,4,6-tri(2-pyridyl)-1,3,5-triazine and tetraphenylborate. Copper is quantitatively adsorbed on this adsorbent in the pH range 1.8–10.5 and at flow-rates of 0.2–10 ml/min. The solid mass consisting of copper complex along with naphthalene is dissolved from the column with 5 ml of dimethylformamide. A calibration curve is obeyed over the concentration range 0.2–10.0 g of copper in 5 ml of dimethylformamide. Eight replicate determinations of 3 g of copper gave a mean absorbance of 0.185 with a relative standard deviation of 1.4%. The characteristic concentration for 1% absorption is 0.0143 g/ml (0.103 gmg/ml for direct AAS in aqueous medium). The interference of various ion and salts has been studied and the proposed method has been employed to the determination of copper in biological and water samples.     

5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) as a sensitizer for singlet oxygen imaging in cells: characterizing the irradiation-dependent behavior of TMPyP in a single cell

Singlet molecular oxygen, a1Delta(g), can be detected from a single cell by its weak 1270 nm phosphorescence (a1Delta(g)-->X3Sigma(g)-) upon irradiation of the photosensitizer 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) incorporated into the cell. The behavior of this sensitizer in a cell, and hence the behavior of the associated singlet oxygen phosphorescence signal, depends on the conditions under which the sample is exposed to light. Upon irradiation of a neuron freshly incubated with TMPyP, the intensity of TMPyP fluorescence initially increases and there is a concomitant increase in the singlet oxygen phosphorescence intensity from the cell. These results appear to reflect a photoinduced release of TMPyP bound to DNA in the nucleus of the cell, where TMPyP tends to localize, and the subsequent relocalization of TMPyP to a different microenvironment in the cell. Upon prolonged irradiation of the cell, TMPyP photobleaches and there is a corresponding decrease in the singlet oxygen phosphorescence intensity from the cell. The data reported herein provide insight into key factors that can influence photosensitized singlet oxygen experiments performed on biological samples.