Fourth Derivative Spectrophotometric Determination of Trace Silver after Preconcentration with the Ion Pair of 2-Nitroso-1-naphthol-4-sulfonic Acid and Tetradecyldimethylbenzylammonium Chloride by Microcrystalline Naphthalene or Column Method

Silver is quantitatively retained as 2-nitroso-1-naphthol-4-sulfonic acid (nitroso-S) and tetradecyldimethylbenzylammonium (TDBA) ion associated complex on microcrystalline naphthalene in the pH range 9.5-11.0 from large volumes of its aqueous Solutions of various alloys and biological samples. After filtration, the solid mass consisting of metal complex and microcrystalline naphthalene was dissolved in dimethylformamide (DMF) and the metal determined by fourth derivative spectrophotometry. Silver can alternatively be quantitatively adsorbed on (nitroso-S)-(TDBA)-naphthalene adsorbent packed in a column at a flow rate of 1-2 ml min-1 and determined similarly. The calibration curve is linear over the concentration range 0.2-30 pg ml-1 of silver in dimethylformamide solution by measuring the distance d4A/cU4 between (606 nm) and (562 nm) with a correlation coefficient of 0.9994 and relative standard deviation of ±1.1%. The analytical sensitivity is calculated to be 0.198(d4A/dA4)/ pg ml-1 from the slope of the calibration curve. The detection limit is 0.15 pg ml-1 for silver at the minimum instrumental settings (signal to noise ratio = 2). Various parameters such as the effect of pH, volume of aqueous phase and interference of a large number of metal ions on the determination of silver have been studied in detail to optimize the conditions for its determination in various complex samples

The Use of Phenanthrenequinonedioxime Supported on Naphthalene for the Preconcentration and Determination of Copper in Alloys and Human Hair

Solid chelating compound, phenanthrenequinonedioxime (PQDO), supported on naphthalene, provides a simple, rapid and economical means of preconcentrating copper in alloys and biological samples. Copper forms a chelate with PQDO supported on naphthalene in the column at pH 1.8—8.4. The metal complex and naphthalene are dissolved out of the column with 5 ml of dimethylformamide (DMF) and the absorbance is measured by an atomic absorption spectrometer at 324 nm. A calibration curve is linear over the concentration range 0.5—12.0 fig of copper in 5 ml of the final solution. The preconcentration factor is 80. The sensitivity for 1% absorption is 0.039 fig/ml (0.153 fig/ml for the direct AAS method from the aqueous medium). The method has been used for the determination of copper in various standard alloys and biological samples

Atomic absorption spectrometric determination of trace cadmium after preconcentration with [1-(2-pyridylazo)-2-naphthol]-naphthalene adsorbent or its complex on microcrystalline naphthalene

19-24Cadmium 1-(2-pyridylazo)-2-naphthol complex is quantitatively adsorbed on microcrystalline naphthalene in the pH range 8.0-10.5. It can also be alternatively adsorbed on [1-(2-pyridylazo)-2-naphthol]-naphthalene adsorbent packed in a column at a flow rate of 1-2 mL/min and the metal determined by flame atomic absorption spectrometrically by measuring the absorbance at 228.8 nm against a reagent blank. About 0.05μg of cadmium can be concentrated in a column from 450 mL of aqueous sample, where its concentration is as low as 0.11ng/mL. The detection limit is 44 pg/mL for cadmium at the minimum instrumental settings. The linearity is maintained in the concentration range 0.11 ng/mL to 0.4 μg/mL cadmium in aqueous solution or 0.0 l to 1.6 μg/mL cadmium in the final DMF solution with a correlation factor of 0.9995. Eight replicate determinations of 0.3 μg/mL of cadmium in final DMF solution give a mean absorbance of 0.150 with a relative standard deviation of 1.6%. The sensitivity for 1% absorption is 8.8 ng/mL in final DMF solution. The interference of a large number of anions and cations on the determination of cadmium after the preconcentration step have been studied and the optimized conditions developed utilized for its trace determination in various alloys and biological samples. The method may also be used for the determination of cadmium in various environmental samples

Derivative spectrophotometric determination of vanadium in alloys and environmental samples after adsorptive extraction of its 2-(5-bromo-2-pyridylazo )-5-diethylaminophenol chelate onto microcrystalline benzophenone

672-675Benzophenone has been used as an extractant for the preconcentration of vanadium as vanadium-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol(5-Br-PADAP) complex from a fairly large volume (400ml) of its aqueous sample in weakly acidic condition (pH 3.5-5.0). The solid mass is dissolved in 5 ml of acetonitrile and quantified by second-derivative spectrophotometry (peak-to-peak method)

Differential pulse polarographic determination of copper in alloys and biological samples after preconcentration with 2-nitroso-l-naphthol-4-sulphonic acid-tetraadecy ldimethylbenzylammonium-naphthalene adsorbent

168-171Copper is quantitatively retained on 2-nitroso-1-naphthol-4-sulphonic acid-tetradecyldimethylbenzylammonium TDBA-naphthalene adsorbent packed in a chromatographic column in the pH range… </span

First derivative spectrophotometric determination of palladium after column preconcentration with 1-(2-pyridylazo )-2-naphthol supported on naphthalene

321-326<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">A solid chelating material, 1-(2-pyridylazo)-2-naphthol (PAN) supported on naphthalene provides a rapid and highly selective means of preconcentrating palladium from a large aqueous volume (-500 mL) of its synthetic samples. Palladium is quantitatively retained on this adsorbent in the <span style="font-size:11.0pt;line-height: 115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:arial;mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">pH <span style="font-size:11.0pt;line-height: 115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">range 3.1-5.0 when its aqueous solution is passed on it at a flow rate of 1-8 mL/min. the solid mass consisting of the adsorbent along with the metal complex is dissolved out of the column with 5 mL of dimethylformamide (DMF) and the metal is determined by first derivative spectrophotometry. The calibration curve is linear over the concentration range 0.3-200 µg of palladium in 5 mL of the final DMF solution by measuring the distance dA/dλ between λ1(680) and λ2(650). Eight replicate determinations of a sample solution containing 20 µg of palladium gave a mean intensity (peak to peak signal between λ1 and λ2)0.138 with a relative standard deviation of 1.5%. The sensitivity of the method is 0.0318 [(dA/dλ)/(µg/mL)]found from the slope of the calibration curve and detection limit is 0.04 µg/mL (signal to noise ratio <span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">= <span style="font-size:11.0pt; line-height:115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">2). Various parameters such as <span style="font-size:11.0pt;line-height: 115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:arial;mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">pH <span style="font-size:11.0pt; line-height:115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">effect, flow rate, volume of aqueous phase and the interference of anions and cations on the estimation of palladium have been evaluated and the developed method is found to be highly selective and sensitive and applied to the determination of trace amounts of palladium in various complex samples corresponding to standard samples.</span

Preconcentration of thallium with 2-nitroso-I-naphthol-4-sulphonic acidtetradecyldimethy lbenzylammonium chloride on microcrystalline naphthalene and its determination by DPP

913-916Thallium(l) is quantitatively retained as 2-nitrosol-naphthol-4 -suIphonic acid-tetradecyldimethylbenzyl-ammonium &nbsp;chloride on microcrystalline naphthalene in the pH range 10-11.5 from its aqueous solution. After adsorption, the metal is desorbed with 10 ml of 1M HCI and determined by differential pulse polarography. The detection limit is 0.2 mg/ml (signal to noise ratio = 2) and the linearity is maintained in the concentration range 0.4-180 mg/10 ml of the final solution (r = 0.9995: rsd = 0.95%). The degree of revcrsibility has also been examined. Various parameters such as the effect of pH, concentrations of aqueous phase, HCl, reagent and naphthalene, shaking time and interference of a number of metal ions and anions on the determination of thallium (I) have been studied to optimize the conditions. The method has been successfully applied for estimation of Tl(l) in environmental and biological samples