Thiothenoyltrifluoroacetone as the Extracting and Colorimetric Reagent for Bismuth

Abstract

Thiothenoyltrifluoracetone (STTA) was used for the simultaneous extraction and direct spectrophotometric determination of bismuth at microgram concentration. About 98.5 μg of bismuth was extracted as the orange-red colored complex with 10 ml of 0.001 M STTA in carbontetrachloride. The extraction was quantitative at pH 6. The system conformed to Beer's Law in the concentration range of 2.5 to 30 μg/ml of bismuth at 460 nm. The method is both sensitive and selective.

The molar absorptivity was 5.6 × 10³ and sensitivity was 0.037 μg/cm². The method is selective as it is possible to accomplish extraction and colorimetrically determination of bismuth in the presence of 1:50 of several ions. Only ions such as cadmium, tin, iron, titanium and nickel interfere seriously. The overall process of extraction and determination takes hardly 30 minutes. The method is reproducible.     

Spectrophotometric determination of vanadium(IV) in the presence of vanadium(V) using Br-PADAP

In the present paper, a simple and sensitive method is proposed for vanadium(IV) determination in the presence of vanadium(V). This is based on the oxidation of vanadium(IV) present in the sample to vanadium(V) by addition of iron(III) cation, followed by a complexation reaction of iron(II) with the spectrophotometric reagent 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP). The iron(II) reacts with Br-PADAP immediately, forming a stable complex with a large molar absorptivity. The vanadium(IV) determination is possible, with a calibration sensitivity of 0.549 g ml^–1, for an analytical curve of 18.8 ng ml^–1 to 2.40 g ml^–1, molar absorptivity of 2.80 × 10⁴ 1 mole^–1 cm^–1 and a detection limit of 5.5 ng ml^–1. Selectivity was increased with the use of EDTA as a masking agent. The proposed method was applied for the vanadium(IV) determination in the presence of several amounts of vanadium(V). The results revealed that 200 g of vanadium(V) do not interfere with determination of 5.00 g of vanadium(IV). The precision and the accuracy obtained were satisfactory (R. S. D.<2%).     

N-m-Tolyl-o-Methoxybenzohydroxamic Acid (m-T-o-MBHA) as a Specific Reagent for Vanadium

Abstract

A high selective and sensitive spectrophotometric method is described for the determination of traces of vanadium(V) using N-m-tolyl-o-methoxybenzohydroxamic acid. The violet complex extracted into chloroform (λ_max = 545 nm) is stable for several days. As little as 0. 05 μg of vanadium is detectable.     

2-(5-Nitro-2-Pyridylazo)-5-(N-Propyl-N-Sulfopropylamino)Phenol as a new analytical reagent for flow-injection spectrophotometric determination of trace vanadium(V)

A flow injection method using 2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol-(Nitro-PAPS) as a new chromogenic reagent is presented for sensitive and rapid determination of vanadium. Nitro-PAPS reacts with vanadium(V) in weakly acidic medium to form a water soluble complex of molar absorptivity of 8.0 × 10⁴L mol^–1 cm^–1 at 592 nm (maximum absorption wavelength), which permits the straightforward application of a flow injection system to the sensitive determination of vanadium. Under the optimum conditions established, a linear calibration graph was obtained in the range 1–120 ng mL^–1. The relative standard deviation for 60 ng mL^–1 vanadium was 2.2% (n = 5) and the limit of detection was 1 ng mL^–1. The sample throughput is about 40 h^–1. Most inorganic and organic anions examined did not interfere even at concentrations of 3000–6000 times of vanadium. Interference from cobalt(II), copper(II) and nickel(II) at 200ng mL^–1 levels can be overcome by the addition of N-(dithio-carboxy)sarcosine. The recoveries for each 20 and 10 ng mL^–1 vanadium added to the river water were 98 and 97%, respectively.The authors express their thanks to Miss Miho Suzuki and Miss Hiroyo Yamada for their experimental assistance in part.     

Analysis of Metal Ions in Environmental Samples - III Synergistic Determination of Vanadium (V) As its Mixed Complex with N-0-Methoxyphenyl-2-Thenohydroxamic Acid and 3-(0-Carboxyphenyl)-1-Phenyltriazine-N-0Xide

Abstract

A highly sensitive, selective, and rapid method for the spectrophotometry determination of vanadium(V) at trace levels is described. The method is based on the selective extraction of vanadium(v) from strongly acidic (3–6 M hydrochloric acid) met ium with solution of N-0-methoxyphenyl-2- thenohydroxamic acid (0MTHA) in chloroform. The extract is then equilibrated with 3-(0-carboxyohenyl)-1-phenyltriazine-N-oxide(CPPTNO) at pH ? 1.5 and the resulting colour is measured at 445 nm. The colour system obeys Beer's law over the range 0–20 -μg/ml of vanadium; the molar absorptivityat the wavelength of maximum absorption (445 nm), and the Sandell sensitivity of the method are 1.1 × 10⁴1. mole^?1 cm^?1 and 0.005 μg/ml respectively.     

Solid Phase Extraction and Spectrophotometric Determination of Silver with 2-(2-Quinolylazo)-5-diethylaminoaniline as Chromogenic Reagent

 A new chromogenic reagent, 2-(2-quinolylazo)-5-diethylaminoaniline(QADEAA), was synthesized. A highly sensitive, selective and rapid method for the determination of silver was developed. It is based on the rapid reaction of silver (I) with QADEAA and the solid phase extraction of colored chelate using reversed-phase separation cartridge. At pH 6.5 in the presence of sodium dodecyl sulfonate (SDS), QADEAA reacts with silver to form a violet chelate in a molar ratio of 1:2 (silver to QADEAA). This chelate was enriched by solid phase extraction. The retained chelate can be eluted from the cartridge with ethanol. In ethanol medium, the molar absorptivity of the chelate is 1.36×10⁵ L·mol⁻¹·cm⁻¹ at 590 nm. Beer’s law is obeyed in the range 0.01–0.6 μg L⁻¹. The relative standard deviation for eleven replicate samples of 0.01 μg L⁻¹ level is 1.9%. The detection limit reaches the 0.02 μg L⁻¹ level. This method shows satisfactory results when used for the determination of silver in water. Correspondence: Department of Chemistry, Yuxi Teacher’s College, Yuxi, 653100, P.R. China. e-mail: hugiufena@163.com Received 19 August 2002; accepted 20 October 2002     

Simultaneous First Derivative Spectrophotometric Determination of Palladium and Nickel Using 2-(2-Thiazolylazo)-5-Dimethylaminobenzoic Acid as an Analytical Reagent

 A simple, rapid, selective, sensitive and economical method has been developed for the simultaneous determination of trace amounts of palladium and nickel in aqueous methanolic medium using 2-(2-thiazolylazo)-5-dimethylam inobenzoic acid as an analytical reagent by first derivative spectrophotometr y. Palladium is determined by measuring base to peak distance at λ=695.0 nm while nickel is estimated by zero crossing method in the mixture. The linearity is maintained between 0.12–1.75 μg mL⁻¹ for palladium and 0.07–1.60 μg mL⁻¹ for nickel in the pH range 2.8–7.2 and 3.4–8.8 respectively. Seven replicate determinations of 1.0 μ g mL⁻¹ of palladium and 0.8 μg mL⁻¹ of nickel in a mixture give a mean signal height of 0.391 for Pd and 0.541 for Ni with relative standard deviations of 0.9% and 1.2%, respectively. The sensitivity of the proposed method is 0.391 (dA/dλ)/(μg mL⁻¹) for palladium and 0.685 (dA/dλ)/(μg mL⁻¹) for nickel. Various parameters have been optimised for the simultaneous determination of palladium and nickel in various complex samples. Received March 30, 1999. Revision November 25, 1999.     

Spectrophotometric Investigation of Vanadium (V)-N-Pyridylaminothioformyl-N'-phenylhydroxylamine

The pink complexes of vanadium (V) and N-pyridylaminothioformyl-N′-phenylhydroxylamine are extractable into chloroform. Spectrophotometric studies show that the 1:2 complex predominates in the acidity range of 2.5-6 N HCl. The values of the stability constants, stepwise and overall, have been calculated following extended Yatsimirskii, Leden and Harvey-Manning methods.     

2-(2-Thiazolylazo)-p-cresol as a spectrophotometric reagent for vanadium determination in the presence of ascorbic acid

The present work describes the use of 2-(2-thiazolylazo)-p-cresol (TAC) as a spectrophotometric reagent for vanadium determination. TAC reacts with vanadium(IV) in the presence of ascorbic acid, forming a red complex with absorption maximum at 525 nm. The following parameters were studied: complex stability, pH effect, amount of TAC, amount of acetate buffer, HEDTA effect, order of addition of reagents and Beer's law validity. TAC can be used for vanadium determination in the pH range 4.6–6.0, with molar absorptivity of 2.11 × 10⁴Lmole^–1 cm^–1 (at525nm). Beer's law is obeyed up to 2.0 g mL^–1. Many cation interferences can be easily eliminated by using HEDTA as a masking agent. Steel reference standards were used to test the proposed procedure and the accuracy and precision obtained were satisfactory.     

Extract-Photometric Determination of Vanadium with Isophthaldihydroxamic Acid

Abstract

The spectrophotometric study of violet complex isophthaldihydroxamic acid-vanadium extracted into solution of trioctylmethylammonium chloride in ethylacetate was made (λ_max = 380 nm, ? = 7500 l.mol^?1.cm^?1; λ_max = 510 nm, ? = 5510 l.mol^?1 .cm^?1; stoichiometries, 1:1 and 1:2, V:reagent). A new method for the extract-spectrophotometric determination of V(V) in the range 14–80 μg of vanadium is proposed.     

Application of the Ion Pair of 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol and Ammonium Tetraphenylborate for Preconcentration of Trace Vanadium and Determination by Third Derivative Spectrophotometry

ＩｎｔｒｏｄｕｃｔｉｏｎＶａｎａｄｉｕｍｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｅｌｅｍｅｎｔｗｈｉｃｈａｆｆｅｃｔｓｔｈｅｐｈｙｓｉｃａｌｐｒｏｐｅｒｔｉｅｓｏｆｓｔｅｅｌ,ａｌｌｏｙｓａｎｄｈｉｇｈｐｕｒｉｔｙｍｅｔａｌｓ .Ｉｔｉｓｗｉｄｅｌｙｄｉｓｔｒｉｂｕｔｅｄｉｎｔｈｅｅａｒｔｈ’ｓｃｒｕｓｔ,ａｎｄｉｔｓｃｏｍｐｏｕｎｄｓｃａｎｂｅｈｉｇｈｌｙｔｏｘｉｃｔｏｍａｎａｎｄａｎｉｍａｌｓａｎｄｃａｕｓｅｅｎｖｉｒｏｎｍｅｎｔａｌｄｉｓｅａｓｅｓｗｈｅｎｒｅｌｅａｓｅｄｉｎｔｈｅａｔｍ…     

Solid Phase Extraction and Spectrophotometric Determination of Mercury in Tobacco and Tobacco Additives with p-Sulfobenzylidenerhodanine as Chromogenic Reagent

A highly sensitive, selective and rapid method for the determination of mercury based on the reaction of mercury(II) with p-sulfobenzylidenerhodanine (SBDR) and the solid phase extraction of the colored chelate with a C₁₈ cartridge has been developed. In the presence of pH 3.8 acetate buffer solution and Tween-80 medium, SBDR reacts with mercury to form a red chelate of a molar ratio of 1:2 (mercury to SBDR). This chelate was enriched by solid phase extraction with a C₁₈ cartridge and eluted from the cartridge with ethanol (containing 5% acetic acid). The enrichment factor of 50 was achieved. In the ethanol medium, the molar absorptivity of the chelate is 1.28×10⁵L·mol^–1·cm^–1 at 545nm. Beers law is obeyed in the range of 0.011.2µgmL^–1 in the measured solution. The relative standard deviation for eleven replicate samples of 0.01µgmL^–1 level is 1.52%. This method can be applied to the determination of mercury in tobacco and tobacco additives with good results.     

Extractive Spectrqphotometric Determination of Vanadium Liith o-Aminobenzo-Hydroxamic Acid

Abstract

A new spectrophotometric method for vanadium determination is proposed. The method is based on the extraction in Adogen-toluene solution of the complex formed between V(V) and o-Aminobenzohydraxámic acid

The method allows determination of 50 to 110 μg of V(V). The error and the apparent molar absorptivity are 1.2% and 5.2 ± 10³ l.mol^?1. cm^?1 respectively. The interferences caused by foreign ions have been established. The method is applied with success to determination of vanadium in petroleum crudes.     

Catalytic Spectrophotometric Determination of Vanadium by Flow Injection Analysis

Determination of trace amount of vanadium in water was studied by flow injection analysis. Catalytic spectrophotometric detection was performed with bromate oxidation of o-phenylenediamine and by addition of tiron as an activator and also as a masking agent. Vanadium can be determined with sample rate of ca. 60–70 samples/hour with in a range of 0.01 ppm to 0.5 ppm V and with r.s.d. 0.555% for 0.1 ppm V and 0.37% for 0.3 ppm V. Interference by Fe(III) can be reduced by using 0.3% NH₄F as a carrier solution.     

A Spectrophotometric Study of the Molybdenum(VI)-1-Pyrrolidinecarbodithioate System

Abstract

A spectrophotometric study of the molybdenum-1-pyrrolidinecarbodithioate complex has shown that the meta1:ligand ratio is 1;2. Both molybdenum(VI) and molybdenum(V) form complexes with almost identical absorption spectra. The conditional extraction constant for the molybdenum(VI)-1-pyrrolidinecarbodithioate in chloroform system has been evaluated as 6.3 × 10¹⁶.     

新显色剂8-(2-羟基-3,5-二硝基苯偶氮)-1,2,4-氨基羟基萘磺酸的合成及其光度法测定钒的研究

本文研究了新显色剂8-(2-羟基-3,5-二硝基苯偶氮)-1,2,4-氨基羟基萘磺酸的合成及其光度法测定钒的条件。在0.4～1.2mol/L盐酸介质中,显色剂与钒(V)形成黄色络合物,其络合比为V(V):R=1:3。摩尔吸光系数为1.4×10~4L·mol~(-1)·cm~(1-)。可在掩蔽剂作用下,不经分离直接测定矿样中的钒。     

新试剂2-(5-硝基-2-吡啶偶氮)-5-二甲氨基苯甲酸分光光度法测定微量钴

本文报道用新试剂2-(5-硝基-2-吡啶偶氮)-5-二甲氨基苯甲酸分光光度法测定微量钴。配合物的表观摩尔吸光系数为1.31×10~5L·mol~(-1)·cm~(-1),Co∶5-NO_2-PAMB=1∶2,Co浓度在0～14μg/25mL范围内服从比耳定律。用于金属有机化合物中微量钴的测定,结果与理论值相符。     

Flow Injection Spectrophotometric Determination of Dipyrone in Pharmaceutical Formulations Using Fe(III) as Reagent

A flow injection spectrophotometric procedure with symmetric merging zones for dipyrone determination in pharmaceutical formulations is proposed. The determination is based on the formation of a blue complex (monitored at a wavelength of 642 nm) yield in the complexation reaction of dipyrone with Fe(III) in acid medium. Under optimum conditions, a calibration curve was obtained from 3.5 to 281 mg L^?1 with a detection limit of 2.8 mg L^?1 and the samples throughput was 80 h^?1. The analytical results obtained for commercial formulation samples by applying the proposed method were in good agreement with labeled values and those obtained by a comparative procedure at a 95% confidence level.     

Vanadium(III) chloride as an effective catalyst for the Pechmann reaction

Good yields of substituted coumarins were obtained by a synthetic method involving the Pechmann reaction using vanadium(III)chloride (VCl₃) reagent to effect this condensation under solvent-free conditions. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 197–200, February, 2006.