Spectrometric Determination of Nitrite in Aqueous Solution by the Diazotization-Coupling Method with p-Aminobenzophenone-N-(1-Naphthyl)-Ethylenediamine

Abstract

Nitrite ion at low concentration is determined spectrometrically by diazotization of p-aminobenzo-phenone and coupling of the resulting diazonium cation with N-(1-naphthy1)-ethylene-diamine to form a reddish-violet coloured water-soluble azo dye with maximum absorption at 555 nm. The method is suitable for the determination of nitrite over the range of 0.04–1.00 ppm. Beer's law is obeyed over this range of concentrations. The observed molar absorptivity and Sandell's sensitivity of the azo dye are 7.0 × 10⁴ mol^?1 cm^?1 and 6.5 × 10^?4 μg cm^?2, respectively. Interferences due to other ions were studied to test the selectivity.     

Colorimetric Determination of Seleniumin Various Environmental Samples

A new reagent system using rhodamine‐B dye for the determination of selenium is described. The method is based on the reaction of selenium with acidified potassium iodide to liberate iodine. The liberated iodine bleaches the pink colour rhodamine‐B, which is measured at 555 nm. Beer's law is obeyed over the concentration range of 1–10 μg of selenium final solution volume of 25 mL (0.04–0.4 ppm) and the apparent molar absorptivity and Sandell's sensitivity was found to be 1.96× 10⁵ l mol^?1 cm^?1 and 0.0004 μg cm^?2, respectively. The method is simple, sensitive, and selective and is satisfactorily applied to micro‐level determination of selenium in various environmental and cosmetic samples.     

Micro-determination of gold using N-cyanoacylacetaldehyde hydrazone

A reliable and rapid procedure for the flotation and micro-determination of Au(III) using N-cyanoacylacetaldehyde hydrazone (CyAH) is proposed. CyAH forms a blue 1:1 complex (K_f=4.1×10⁵ mol^?1l^?1) with Au(III) at pH 3–7. The maximum absorbance is obtained after 7 min; instantaneously by adding 3.3×10^?3 mol/l H₃PO₄ or by heating to 55°C. Beer's law is obeyed for 1–30 ppm of Au(III) with a molar absorptivity of 0.3×10⁴ l mol^?1 cm^?1 at 550 nm.     

Colorimetric Determination of Sulphur Dioxide and Sulphites in Various Environmental Samples

Rhodamine‐B has been proposed as a simple and sensitive colorimetric reagent for the estimation of sulphur dioxide in air. The air sample containing sulphur dioxide is passed through the absorbing solution of aqueous potassium iodate and N‐chlorosuccinimide to liberate iodine. The liberated iodine bleaches the pinkish red coloured rhodamine‐B dye, which measured at 555 nm. Beer's law was obeyed in the range of 0.5–5.0 μg, of sulphite per 25 mL (0.02–0.2 ppm) equivalent to 0.4–4.0 μg of sulphur dioxide (0.016–0.16 ppm). The molar absorptivity and Sandell's sensitivity were found to be 4.56 × 10⁵ l mol^?1 cm^?1 and 0.00017 μg cm^?2, respectively. The method has been suitably modified and successfully applied to the determination of sulphites in water after liberation of sulphur dioxide in acidic medium.     

Isonitroso-4-Methyl-2-Pentanone for Solvent Extraction and Spectrophotometric Determination of Palladium (II) at Trace Level

Abstract

Isonitroso-4-methyl-2-pentanone (HIMP) is proposed as a new reagent for extraction and photometric determination of Pd(II). The reagent forms a yellow complex with palladium in the pH range 4.0-5.0. The complex extracted into chloroform was measured at 330 nm. The molar absorptivity was found to be 5.37 × 10³ 1 mol^?1 cm^?1 and Sandell's sensitivity 20 ng cm^?2 Beer's law was obeyed over the concentration range 0.1-10.0 μg/ml of palladium. The method is applicable for palladium estimation in Ores and catalysts.     

A Sensitive Spectrophotometric Determination of Nitrite in Water and Soil

A highly sensitive spectrophotometric method for the determination of nitrite in water and soil has been developed. The reaction of nitrite with acidified potassium iodide to liberate iodine which oxidizes leuco‐crystal violet (LCV) to form crystal violet having absorption maxima at 590 nm forms the bases of this method. In aqueous medium the system obeys Beer's law in the range of 0.1 to 1.0 μg per 25 mL (0.004–0.04 ppm), while in an extractive system the range is 0.025–0.25 μg in 100 mL (0.00025–0.0025 ppm). The molar absorptivity and Sandell's sensitivity were found to be 1.54 × 10⁶ 1 mol^?1 cm^?1 and 44 pg cm^?2, respectively.     

Spectrophotometric Determination of Sulphathiazole

Abstract

A new, rapid, simple, selective and sensitive method for the spectrophotometric determination of sulphathiazole is described. The drug forms a yellow coloured complex with Pd(II) in alkaline medium (1 M NaOH). The drug complex exhibits maximum absorbance at 410 nm, with a molar absorptivity of 1.9 × 10³ 1 mol^?1 cm^?1. Effects of molarity of NaOH, reagent concentration on the proper complex formation are discussed. The system obeys Beer's law in the concentration range of 10-160 ppm of sulphathiazole.     

A Sensitive Colorimetric Reagent for the Determination of Cyanide and Hydrogen Cyanide in Various Environmental Samples

A sensitive reagent system is proposed for the determination of cyanide and hydrogen cyanide in various environmental samples. The method is based on the conversion of cyanide into cyanogen bromide followed by its reaction with pyridine to form glutaconic aldehyde. The glutaconic aldehyde so formed is coupled with p‐aminoacetophenone forming yellow‐orange polymethine dye measured at 445 nm. The colour system obeys Beer's law in the range of 0.01–0.16 ppm of cyanide inaqeous phase and 0.002–0.03 ppm in extracting system. The molar absorptivity and Sandell's sensitivity were found to be 6.51 × 10⁵ l mol^?1 cm^?1 and 0.0001 μg cm^?2, respectively. The method has been successfully applied for the determination of cyanide in air, industrial effluent, biological samples, and in the pesticide acrylonitrile.     

Selective Spectrophotometric Determination of Palladium (II) With 2-(5-Bromo-2-Pyridylazo)-5-(Diethylamino)-Phenol

Abstract

A spectrophotometric study of the Pd(II) complex of a reagent 2-(5-Bromo-2-Pyridylazo)-5-(diethylamino)-Phenol (5-Br-PADAP) is presented. A violet complex is formed at pH 3.53, and shows maximal absorbance at 585 nm with molar absorptivity of 3.86 × 10⁴ 1. mol^?1 cm^?1. Beer's law is obeyed up to 50 μ of Pd(II). The method offers the advantages of simplicity, high precision, requires no extraction and is very selective, where 5.0 mg Pt(VI) and 0.3 mg Au(III) ions do not interfere.     

Determination of Vanadium with Chlorosubstituted Hydroxamic Acids for Photometric and Atomic Absorption Spectrophotometric Determination

Abstract

The eight newly synthesized chlorosubstituted hydroxamic acids are described for the extraction and spectrophotometric determination of vanadium. The sensitive and selective reagent, N-m-Chlorophenylpalmito hydroxamic acid, (m-CPPHA), which gives violet coloured vanadium complex was extracted with chloroform from 6M HCl. The violet coloured complex thus obtained has a maximum absorbance at 520 nm and molar absorptivity 4.9 ± 10³1mol^?1cm^?1. The Beer's law obeyed in the region 0.50-12.0ppm. Effects of acidity, reagent concentration, diverse ions have also been investigated. A comparison has been made with atomic absorption spectrophotometric method. Vanadium has been determined in the environment, e.g. plant, soil, rock, etc.     

1,3-Cyclopentanedione bis(4-methylthiosemicarbazone) monohydrochloride as a spectrophotometric reagent for the determination of lodate in acetic and perchloric acid media

1,3-Cyclopentanedione bis(4-methylthiosemicarbazone) monohydrochloride produces colored solutions with iodate ions in acid medium. The yellow color obtained has been used to proposed Spectrophotometric methods for determination of IO₃^? in the concentration range 1.0–11.0 ppm in acetic acid medium (molar absorptivity 1.08 × 10⁴ liters mol^?1 cm^?1 at a wavelength of 415 nm) and 0.5–8.0 ppm in perchloric acid medium (molar absorptivity 2.05 × 10⁴ liters mol^?1 cm^?1 at a wavelength of 400 nm).     

Extraction,Spectrophotometric and Atomic Absorption Spectrophotometric Determination of Molybdenum with Caffeic Acid and Application in High Purity Grade Steel and Environmental Samples

Abstract

A new selective and sensitive method for extraction of yellow Mo (VI)-caffeic acid complex with a liquid ion exchanger, Aliquat 336 from 4.0 pH, and spectrophotometric determination of molybdenum in trace amounts is described. the molar absorptivity of the complex is 1.1 × 10⁵ 1 mol^?1 cm^?1 at 340 nm and the colour system obeys Beer's law in the range 0.04–0.99 ppm of Mo(VI). the molybdenum is also determined with AAS and the method is applied for its determination in steel and environmental samples.     

Extraction-Spectrophotometric Determination of Fluoride Using N-Phenylbenzohydroxamic Acid

Abstract

Fluoride gives a very stable complex with scandium and, hence, by determining the unreacted scandium, the fluoride content can be calculated. Excess scandium is reacted with an ethanolic solution of N-benzoylphenylhydroxylamine (BPHA) at pH 6.0, and the scandium-BPHA complex is extracted into isoamyl alcohol. Scandium is determined spectrophotometrically after adding xylenol orange. Beer's law for fluoride is obeyed in the range of 0.05 –1.5 ppm; the molar absorptivity is 1.94×10⁴ 1 mol^?1 at 565 nm. The procedure is applicable for the determination of fluoride in various types of samples.     

Spectrophotometric method for determination of atrazine and its application to commercial formulations and real samples

A simple sensitive spectrophotometric method has been developed for the determination of atrazine in herbicide formulations and real samples. The method was based on the reaction of atrazine with pyridine to form a quaternary halide which in the presence of alkali forms a carbinol base. The heterocyclic ring of the carbinol base breaks and forms the glutaconic dialdehyde. The glutaconic dialdehyde group was coupled with sulfanilic acid to form a yellow coloured product having λ _max 450 nm or coupled with aniline to form a orange red coloured product having λ _max 480 nm. The Beer's law was obeyed over the range from 0.1 to 25 µg mL^?1 and molar absorptivity 1.5 × 10⁴ L mol^?1 cm^?1 for sulfanilic acid, and from 0.08 to 12 µg mL^?1 and molar absorptivity 1.3 × 10⁴ L mol^?1 cm^?1 for aniline were observed. The reaction conditions and other analytical parameters were optimised. The proposed method has been successfully applied for the analysis of commercial formulations and real samples.     

Extraction and Spectrophotometric Determination of Zirconium(IV)

Abstract

A sensitive and selective method for the extraction and spectrophotometric determination of Zr(IV) with N-p-chlorophenyl-3,4-,5-trimethoxycinnamohydroxamic acid (PTCHA) has been developed. The binary complex of Zr(IV)-PTCHA is extracted from 2–6 M HCl into chloroform, having a maximum absorbance at 385 nm; molar absorptivity 2.1 × 10⁴ 1 mol^?1 cm^?1. A ternary complex with xylenol orange (Zr-PTCHA-XO) have been studied in chloroform-ethanol media, which absorbs at 540 nm; molar absorptivity 4.3 × 10⁴ 1 mol^?1 cm^?1. The present method is applied for the analysis of zirconium in standard samples.     

2-(8-quinolylazo)-4,5-diphenylimidazole — a sensitive extraction spectrophotometric reagent for mercury

Mercury(II) reacts with 2-(8-quinolylazo)-4,5-diphenylimidazole in aqueous solution; the complex can be extracted with chloroform or 1,2-dichloroethane at pH 4.5–9.5 to give a stable reddish-purple solution. The system conforms to Beer's law; the optimal range in chloroform is 0.05–2 ppm mercury (1-cm cells). Of 25 metal ions investigated, only copper and vanadium interfere seriously. The proposed method is exceptionally sensitive; the molar absorptivity in the chloroform extract is 7.3 × 10⁴ l mol^?1 cm^?1 at 580 nm; the Sandell sensitivity is 0.0027μg Hg cm^?2.     

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.     

Study on the Solid Phase Extraction of Hg(II)‐ABR Chelate with C18 Disks and its Application to the Determination of Mercury in Tobacco and Tobacco Additives

A highly sensitive, selective and rapid method for the determination of mercury based on the rapid reaction of mercury(II) with 5‐(p‐aminobenzylidene)‐rhodanine (ABR) and the solid phase extraction of the colored chelate with C₁₈ disks has been developed. In the presence of pH = 3.5 sodium acetate‐acetic acid buffer solution and Emulsifier‐OP medium, ABR reacts with mercury(II) to form a red chelate of a molar ratio 1:2 (mercury to ABR). This chelate was enriched by the solid phase extraction with C₁₈ disks and eluted the retained chelate from the disks with dimethyl formamide (DMF). The enrichment factor of 50 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.16 × 10⁵ L.mol^?1.cm^?1 at 540 nm. Beer's law is obeyed in the range of 0.01?3 μg/mL in the measured solution. The relative standard deviation for eleven replicated samples of 0.01 μg/mL level is 1.83%. This method was applied to the determination of mercury in tobacco and tobacco additives with good results.     

Direct and Derivative Spectrophotometric Determination of Zinc with 2,4-Dihydroxybenzaldehyde Isonicotinoyl Hydrazone in Potable Water and Pharmaceutical Samples

A simple and sensitive spectrophotometric method is developed for the determination of zinc in aqueous solutions. The metal ion forms a greenish-yellow colored complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range of 4–10. The complex shows maximum absorbance at 390 nm and in the pH range of 6–8. Beer's law is obeyed in the range 0.10–1.50 μg/mL of Zn(II). The molar absorptivity and Sandell's sensitivity are 3.55 × 10⁴ mol⁻¹ cm⁻¹ and 0.0016 μg/cm², respectively. The composition of the complex is 1 : 1. The effect of interfering ions has been studied, and the method was applied to the determination of zinc(II) in potable water and pharmaceutical samples. A fast derivative spectrophotometry method is also proposed for the determination of zinc in the range 0.06–1.60 μg/mL, which is more sensitive than the zero order method. __________ Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 9, 2005, pp. 933–937. Original Russian Text Copyright ? 2005 by Sivaramaiah, Raveendra Reddy. The text was submitted by the authors in English.     

Extractive spectrophotometric determination of nitrite in polluted waters

Nitrite is diazotised with p-nitroaniline in hydrochloric acid and coupled with 8-quinolinol in alkaline medium to give a purple azo dye (λ_max = 550 nm, ? = 3.88 × 10⁴ l mol^-1 cm^-1). Extraction of the dye into 3-methyl-1-butanol shifts the absorption maximum to 570 nm and improves the apparent molar absorptivity to 5.852 × 10⁴ l mol^-1 cm^-1. Beer's law is obeyed for 0.01–0.06 ppm nitrite. The Sandell sensitivity is 0.00078 μg cm^-2. The method is applicable to polluted waters.