Simultaneous determination of titanium and molybdenum in steel samples using derivative spectrophotometry in neutral micellar medium

A simple, selective and sensitive spectrophotometric method has been developed for the individual and simultaneous determination of Ti(IV) and Mo(VI) using resacetophenone p-hydroxybenzoylhydrazone (RAPHBH) in presence of Triton X-100, without any prior separation. Beer's law is obeyed between 0.13-1.2 microg mL-1 and 0.18-1.90 microg mL-1 concentration of Ti(IV) and Mo(VI) at 455 nm and 405 nm, respectively. The molar absorptivity and Sandell's sensitivity of the coloured complexes at pH 3.0 are 3.1x10(4) L mol-1 cm-1, 4.2x10(4) L mol-1 cm-1, and 1.6 ng cm-2, 2.3 ng cm-2 for Ti(IV) and Mo(VI), respectively. The stoichiometry of the complexes were found to be 1:2 and 1:1 (metal:ligand) for Ti(IV) and Mo(VI), respectively. These metal ions interfere with the determination of each other in zero-order spectrophotometry. The first derivative spectra of these complexes permitted a simultaneous determination of Ti(IV) and Mo(VI) at zero crossing wavelengths of 500.0 nm and 455.0 nm, respectively. The effect of foreign ions in the determination of Ti(IV) and Mo(VI) were investigated. The proposed method has been successfully applied for the determination of titanium and molybdenum in standard alloy steel, mineral and soil samples.     

Spectrophotometric method for the determination of manganese with phenylfluorone in the presence of Triton X-100 and cetylpyridinium chloride in pharmacological preparations and vegetable fertilizers

A simple and very sensitive method for the spectrophotometric determination of manganese in pharmacological preparations and vegetable fertilizers is proposed. The method is based on the formation of a blue coloured complex of Mn (II) with 9-phenyl-2,3,7-trihydroxy-6-fluorone (PF) in the presence of cetylpyridinium chloride (CP) and Triton X-100. Optimum concentrations of PF, CP, Triton X-100 and pH ensuring maximum absorbance were defined. The complex Mn(II)-PF-CP-Triton X-100 shows maximum absorbance at 591 nm with the molar absorptivity value 1.77x10(5 )L mol(-1 )cm(-1). The detection limit of the method is 0.004 microg mL(-1). The Beer's law is obeyed for manganese concentrations in the range 0.02-0.2 microg mL(-1). The effect of foreign ions was elucidated. The statistical evaluation of the method was carried out for six determination using 5 microg Mn and the following results were obtained: standard deviation 0.021, confidence interval 5.05+/-0.05 microg Mn. The method has been applied for the determination of manganese in pharmacological preparations (Biovital, Kinder Biovital) and vegetable fertilizers (Hydrovit 100, Florovit).     

The use of phenylfluorone in the presence of cetylpyridinium chloride and Triton X-100 for the spectrophotometric determination of copper(II) in blood serum

A simple and sensitive spectrophotometric method for determination of copper(II) is based on the formation of a blue coloured complex of Cu(II) with 9-phenyl-2,3,7-trihydroxy-6-fluorone (PF) in the presence of cetylpyridinium chloride (CP) and Triton X-100, has been developed. Optimum concentrations of PF, CP, Triton X-100 and pH ensuring maximum absorbance were defined. The complex Cu(II)-PF-CP-Triton X-100 shows maximum absorbance at 595 nm with a molar absorptivity value of 9.67x10(4) l mol(-1) cm(-1). The detection limit of the method is 0.028 mug ml(-1). Beer's law is obeyed for copper concentrations in the range 0.04-0.4 mug ml(-1). The studies of the effect of foreign ions on determination of copper, show that the selectivity of the method is poor. The cations of alkali metals and anions Br(-), Cl(-), I(-), F(-), NO(2)(-), NO(3)(-), CH(3)COO(-), SO(4)(2-), S(2)O(3)(2-), PO(4)(3-), citrates (examined in 1000-fold molar excess over copper) do not affect the determination. All cations forming complexes with PF have an interfering effect. The statistical evaluation of the method was carried out for six determinations using 10 mug of Cu and the following results were obtained: the standard deviation, SD=0.042, the confidence interval mu(95)=10.1+/-0.1 mug Cu. The method has been applied for determination of copper in blood serum.     

Rapid spectrophotometric method (aqueous and extractive) for the determination of titanium in silicate rocks

A sensitive and highly selective aqueous as well as extractive spectrophotometric method has been developed for the determination of titanium(IV) using 2,3-dihydroxynaphthalene (H(2)ND) as a chromogenic agent. The reagent (H(2)ND) forms a 1:3 (TiOH(3+):ligand) complex at pH 4-9. The molar absorptivity and Sandell's sensitivity are 3.2 x 10(4) l . mol(-1)mol . cm(-1) and 0.001 microg/cm(2), respectively at lambda(max) 375 nm. The method has been found highly selective for Ti(IV) determination in rock samples. Solvent extraction of Ti(IV) in ethylacetate greatly improves the detection limit of the method. The method has been successfully applied to diverse silicate rock samples and results obtained are favourably comparable with those obtained from the tiron method. The reagent (H(2)ND) used in the present investigation is a much better variant than tiron for titanium(IV) determination in silicate rock samples in terms of sensitivity, selectivity, operational simplicity and economy.     

Determinaton of trace amounts of titanium by flame atomic absorption spectrometry after cloud point extraction

In this work a cloud-point extraction has been used for the preconcentration of the trace amounts of titanium after complex formation with morin (2′,3,4′,5,7-pentahydroxyflavone) using Triton X-114 as surfactant. The chemical variables affecting the phase separation and the viscosity affecting the detection by flame atomic absorption spectrometry (FAAS) were optimized. At pH 4.5, preconcentration of 50 mL of sample in the presence of 0.08% Triton X-114 and 1.0 × 10^?4 M morin enabled the detection limit (c _L = 3S _b/m) of 2.9 ng/mL titanium and linear range 0.02–2.0 μg/mL to be achived. The preconcentration factor was 61, and the relative standard deviation was 3.8% for 0.1 μg/mL solution of Ti(IV) by repeated assays (n = 9). The proposed method has been applied to the determination of titanium in well water, spiked water and plant (Haloxylon).     

A highly sensitive spectrophotometric method for determination of micro amounts of arsenic

A highly sensitive spectrophotometric method for determination of arsenic, based on the formation of an ion-association complex between arsenoantimonomolybdenum blue and Malachite Green, has been developed. The ion-association complex is soluble in the presence of Triton X-305, so arsenic can be determined directly in aqueous solution. The apparent molar absorptivity for arsenic is 1.13 x 10(5) l.mole(-1).cm(-1) at 640 nm. Beer's law is obeyed for 0-5 mug of arsenic. The lower limit of determination (absorbance = 0.01) is 4 ng ml in the final solution.     

Triton X-100存在下镉试剂分光光度法测定痕量铊(III)

本文首次提出了在Triton X-100存在下, 以镉试剂作显色剂于水相直接分光光度法测定了痕量铊, 结果表明: 该体系具有很高的灵敏度, 是目前分光光度法测定铊的最灵敏方法之一.     

非离子表面活性剂的雾点研究-电解质的影响

研究了１－１型钠盐对五种非 离子表面活性剂水溶液雾点的影响，有九种钠盐使雾点下降，下降的依次是ＩＯ＾－３＞ＯＨ＾－＞Ｆ＾－＞ＣＨ３ＣＯＯ＾－＞ＢｒＯ＾－３＜＞Ｃｌ＾－＞Ｂｒ＾＿＞ＣｌＯ３＾－≥ＮＯ＾－３；有三种钠盐使雾点升高，升高的效率依次是ＣＮＳ＾－＞ＣｌＯ＾－＞Ｉ＾－。     

Anodic stripping voltammetric determination of titanium(IV) using a carbon paste electrode modified with cetyltrimethylammonium bromide

A method is described for the voltammetric determination of titanium(IV) using a carbon paste electrode modified in situ with cetyltrimethylammonium bromide. The cationic micellar surfactant adsorbs onto the electrode particularly at negative potentials, simultaneously preconcentrating titanium(IV) as the oxalate complex with reduction to titanium(III). Anodic stripping voltammetry exploiting reoxidation can be used for the determination of trace levels of titanium(IV). Linearity between current and concentration exists between 5 and 160 mug l(-1) Ti(IV) (preconcentration time 2 min). The limit of detection (calculated as 3sigma) is 0.1 mug l(-1), with a preconcentration time of 10 min.     

Synergic extraction and spectrophotometric determination of titanium(IV)

A method has been developed for the synergic extraction and spectrophotometric determination of Ti(IV) with N-hydroxy-NN'-diphenylbenzamidine and thiocyanate. The yellow ternary complex, extracted into chloroform from dilute sulphuric acid medium (pH = 1.5+/-0.1), has maximum absorbance at 390 nm (molar absorptivity 1.3 x 1O(4) 1.mole(-1). cm(-1)). The method is free from interference from a large number of foreign ions and is recommended for the determination of titanium in steel.     

A new method for the determination of the critical micelle concentration of Triton X-100 in the absence and presence of beta-cyclodextrin by resonance Rayleigh scattering technology

A new method for the determination of the critical micelle concentration (CMC) of Triton X-100 in aqueous solution and beta-cyclodextrin solution by resonance Rayleigh scattering (RRS) has been developed. The method is based on the measurement of the RRS intensity of different concentration of Triton X-100 in aqueous solution and beta-cyclodextrin solution (6.0 x 10(-4) mol l(-1)). When the RRS intensities were plotted against the concentration of Triton X-100, an inflection point appeared at the Triton X-100 concentration of 5.0 x 10(-4) mol l(-1) in aqueous solution and 1.1 x 10(-3) mol l(-1) in beta-cyclodextrin solution, respectively. These values of concentration corresponded to the CMC of Triton X-100 in aqueous solution and beta-cyclodextrin solution, which also agreed closely with the results reported by surface tension and UV-Vis absorption spectrophotometry. Therefore, the present RRS method is very convenient, rapid and accurate and can be used as a new technology for the determination of CMC values of surfactants without any probe. The relationship between the RRS intensity and the concentration, aggregate state and the aggregate molecular size of Triton X-100 has been primarily discussed.     

铀-2-(3,5-二溴-2-吡啶偶氮)-5-二乙氨基苯酚-Triton X-100析相体系的研究及应用

本文研究了铀-2-(3,5-二溴-2-吡啶偶氨)-5-二乙氨基苯酚(3,5-diBr-PADAP)-Triton X-100析相光度体系,建立了矿石中微量铀的测定方法,在pH 7.5三乙醇胺-盐酸介质中,将胶束溶液在 95±1℃加热 1h.络合物即被Triton X-100相完全富集.络合物最大吸收峰位于565nm.摩尔吸光系数为1.02×10～5L·mol～(-1)·cm～(-1),铀含量在0～12μg/5mL服从比耳定律.采用TBP萃淋树脂分离干扰离子,测定矿石中微量铀,结果满意.     

Preconcentration of Ti(IV) in Ore and Water by Cloud Point Extraction and Determination by UV-Vis Spectrophotometry

Trace amounts of titanium(IV) were determined with a simple and selective method based on cloud point extraction. Preconcentration of titanium from aqueous solution was performed using Triton X-114 surfactant and 4-(2-pyridylazo) resorcinol as complexing agent. After centrifugation, the surfactant- rich phase was removed, diluted with water and ethanol, transferred into a 500 μL quartz cell, and its absorbance was measured at 520 nm. The effect of experimental conditions influencing the extraction process was considered. In the optimum conditions, linearity ranges was 0.01–0.1 with the correlation coefficients (R²) of 0.9903. The limits of detection was 0.005. The method was successfully used for the determination of titanium(IV) in the samples of ore and river water with relative recovery of 98?99%.     

Determination of trace vanadium in sea cucumbers by ultrasound-assisted cloud point extraction and graphite furnace atomic absorption spectrometry

An ultrasound-assisted cloud point extraction (CPE) procedure was used for preconcentration and determination of vanadium by graphite furnace atomic absorption spectrometry. The vanadyl(IV) complex with ascorbic acid form a hydrophobic complex with 4-(2-pyridylazo) resorcinol (PAR) in a micelle medium, which is stable under our working conditions, and followed by its extraction into Triton X-100 surfactant-rich phase. The main factors affecting CPE efficiency, such as pH, concentrations of PAR, ascorbic acid and Triton X-100, incubation temperature, frequency and equilibration time of ultrasonic bath were investigated in detail. Under the optimum conditions, preconcentration of 10 mL sample gave a preconcentration factor of 36.4 and a detection limit of 4.0 µg kg^?1. The proposed method was successfully applied to determination of vanadium in sea cucumbers with satisfactory results.     

Determination of Trace Titanium by Solid Substrate－Room Temperature Phosphorimetry with 4,5－Dibromophenylfluorone as Luminescent Ligand and Triton X－100 as Sensitizer

A new highly sensitive solid substrate room temperature phosphorimetry for the determination of trace titanium is proposed based on the sensitization of Triton X-100 to the SS-RTP intensity of 4, 5-dibro-mophenylfluorone-titanium complex adsorbed on the filter paper substrate modified by gelatin. When Triton X-100 was added into the luminescence system, the RTP intensity was raised 3 times stronger than that of the system without Triton X-100. The linear dynamic range of the new method is 0. 64 ～ 3.2 fg/spot (0. 4 μL) with a detection limit of 12.8 ag/spot, and the regression equation of the working curve is △Ip = 482. 0 119.5mTi（Ⅳ) (fg/spot), the correlation coefficient r= 0. 9992, n = 6. The phosphorescence lifetime (r= 0. 85 ms) was also determined. The recoveriesCand RSD) for the determinations of titanium in human hair and tea samples were 101.0% (3. 0%) and 99. 97% (4. 2%), respectively.     

New Spectrophotometric Method for the Determination of Titanium in Soil and Standard Geochemical Samples

Abstract

In the present communication a simple and rapid spectrophotometric method for the determination of titanium is described. The method is based on the reaction of Ti(IV) with a newly synthesized reagent, 6-(4-nitrophenylazo)-3,4,5-trihydroxy benzoic acid (NATHB), in ethanol medium at pH 3.2 to 4.2. The complex exhibits an absorption maximum at 495 nm and Beer's law is valid over the range of 0.04 – 1.00 μg.ml^?1 Ti. The molar absorptivity is 3.48 × 10⁴ dm³.mole^?1. cm^?1. Most of the foreign metal ions and anions do not produce any colorations with NATHB at selected conditions. Based on these results, a simple and direct spectrophotometric method with high selectivity and sensitivity was proposed. The method has been successfully applied for the determination of titanium in 5 soil and 3 standard geochemical samples.     

Ti(IV) ion-imprinted polymer as a new selective sorbent for extraction and pre-concentration of trace amounts of titanium ions in different samples

ABSTRACT

In this paper, a novel, simple, selective and effective solid phase extraction method based on ion-imprinted polymer (IIP) technology and flame atomic absorption spectrometry (FAAS) for separation and pre-concentration of trace amounts of titanium (IV) ions was reportd?. It was obtained by precipitation polymerisation by using 2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one titanium (IV) complex abbrivated as Ti(IV)-(morin), as the template molecule. After polymerisation, leaching the polymer in HNO₃ (50% (v/v) solution caused formation cavities in the polymer. Characterisation studies of the ?Ti(IV)-imprinted polymer (Ti-IP) was performed by FT-IR, UV-Vis and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) techniques and then, the effective factors on extraction were optimised. A sensitive response to Ti(IV) within a concentration range between 0.01 and 4.0 μg mL^?1 was achieved under the optimum conditions. A total of 10.0 ng mL^?1 and 80.0 mg g^?1 were obtained as limit of detection (LOD, 3Sb/m) and maximum adsorption capacity, respectively. The relative standard deviation (RSD) for eight replicates detections of 0.2 μg mL^?1 of Ti(IV)? was found to be 2.8%. By this method, pre-concentration factor (PF) of 100 was obtained. Successfully applying this method in the water and standard samples, reasonable results were obtained for the extraction and pre-concentration of the titanium ions.     

High-performance liquid chromatography of micelle-solubilized complexes-IV Reversed-phase ion-pair chromatography of metal-3,5-diBr-PADAP-Triton X-100 complexes

The micellar solubilization complex systems of V(V), Cu(II), Zr(IV), Pd(II), Fe(III), Ni(II) and Co(II) with 3,5-diBr-PADAP and Triton X-100 have been investigated by HPLC on an ODS (5 x 250 mm) column with a ternary eluent of methanol-acetone-acetone-water containing TBA(+) and acetate buffer (pH 3.0) at 600 or 572 nm wavelength for the detection of the complexes. An HPLC-spectrophotometric method for determination of seven metal ions has been developed. The peak height calibration curves are linear up to 50-100 mu/1, metal ion concentration. The relative standard deviations for the determination of 30.0 mu/1 metal ion were 0.9-1.6% and the detection limits (S/N = 3) were 1.1-3.6 mug/1.     

Wetting and adsorption: I. The structure of adsorbed layer of nonionic surfactants at SiO2/water and SiO2/cyclohexane interface

Based on the adsorption of Triton X-100 on silica/water and silica/cyclohexane interfaces and the adsorption of Triton X-305 on silica/water interface, two adsorption models have been proposed. On silica/cyclohexane interface, the adsorption of Triton X-100 is monomolecular layer. The molecules in the monolayer are presumed to be attached to the silica surface by their EO chain such that their hydrocarbon chain are exposed to the cyclohexane phase. On silica/water interface, the adsorption of Triton X-100 or Triton X-305 is bimolecular layer. The surfactant molecules orientated in the first layer are similar with that on the silica/cyclohexane interface. The molecules in the second layer are postulated to adsorb on those of the first in the opposite orientation, with EO chain directed toward the adsorption medium. The contact angle of quartz-water-cyclohexane (θ_W) as a function of the concentration of Triton X-100 and Triton X-305 in water has been measured with quartz plate employing the captive drop (cyclohexane) technique. The observed θ_W (measured through water) rose from < 10° to a maximum of about 120° for Triton X-100 and of about 40° for Triton X-305 as the concentration of surfactant in water increased, and then fell, as the concentration increased further. The results are consistent with the proposed adsorption models.     

Rapid and Sensitive Spectrophotometric Determination of Hafuium(IV) With 2-(5-Bromo-2-Pyridylazo)-5-Diethylaminophenol

Abstract

Hafnium(IV) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in the pH range 3.3–11.0 to yield a sparingly soluble red-coloured chelate that can be dissolved with Triton X-100. Effect of initial pH of metal ion and order of addition of reagents was studied in detail. The 1:3 complex adheres to Beer's law over the concentration range 0.02–1.12 μg/ml of Hf(IV), has a molar absorptivity 1.33x10⁵ 1 mol^?1cm^?1, Sandell sensitivity 1.3 ng cm^?2, formation constant (log K) 11.94 and the method had a relative standard deviation of ± 1.5%. Effect of 60 diverse ions on the determination of hafnium(IV) was studied. This fairly selective method is the most sensitive so far reported for the spectrophotometric determination of hafnium(IV).