Simultaneous determination of copper, bismuth and lead by adsorptive stripping voltammetry in the presence of thymolphthalexone.

A novel, sensitive and selective adsorptive stripping procedure for simultaneous determination of copper, bismuth and lead is presented. The method is based on the adsorptive accumulation of thymolphthalexone (TPN) complexes of these elements onto a hanging mercury drop electrode, followed by reduction of adsorbed species by voltammetric scan using differential pulse modulation. The influences of control variables on the sensitivity of the proposed method for the simultaneous determination of copper, lead and bismuth were studied using the Derringer desirability function. The optimum analytical conditions were found to be TPN concentration of 4.0 microM, pH of 9.0, and accumulation potential at -800 mV vs. Ag/AgCl with an accumulation time of 80 s. The peak currents are proportional to the concentration of copper, bismuth and lead over the 0.4-300, 1-200 and 1-100 ng mL(-1) ranges with detection limits of 0.4, 0.8 and 0.7 ng mL(-1), respectively. The procedure was applied to the simultaneous determination of copper, bismuth and lead in the tap water and some synthetic samples with satisfactory results.     

Simultaneous spectrophotometric determination of trace amounts of cobalt, nickel, and copper using the partial least-squares method after the preconcentration of their 2-aminocyclopentene-1-dithiocarboxylate complexes on microcrystalline naphthalene

A spectrophotometric method for the determination of trace amounts of cobalt(II), nickel(II), and copper(II) after the adsorption of their 2-aminocyclopentene-1-dithiocarboxylate complexes on microcrystalline naphthalene has been developed. These complexes are adsorbed on microcrystalline naphthalene at pH 4.5 by shaking for 5 min. The formed solid mass is separated by filtration, and dissolved in dimethylformamide. The absorption spectra were processed using the partial least-squares multivarate calibration method for the analysis of a ternary mixture of Co(II), Ni(II), and Cu(II). The detection limits for Co(II), Ni(II), and Cu(II) were 3.3, 10.0, and 0.8 ng/mL, respectively. The total relative standard error for applying the method to 20 synthetic samples in the concentration ranges of 20–400 ng/mL Co(II), 60–400 ng/mL Ni(II), and 4–400 ng/mL Cu(II) was 1.53%. The proposed method was also successfully applied to the determination of Co(II), Ni(II), and Cu(II) in alloys. The text was submitted by the authors in English.     

Synthesis of 1,5-bis(4,6-dichloro-1,3,5-triazinylamino)naphthalene and its application to spectrofluorimetric determination of aniline

A new fluorescent reagent 1,5-bis(4,6-dichloro-1,3,5-triazinylamino)naphthalene (DTAN) was synthesized. The optimum conditions of fluorescent reaction of this reagent with aniline (PA) were also investigated. Based on this reaction, a new spectrofluorimetric method was developed for the determination of aniline. The fluorescent intensity was directly proportional to the concentration of aniline in the ranges 0.05-2.0 microg mL(-1) and 2.0-50 microg mL(-1) with the detection limits of 34 ng mL(-1) and 90 ng mL(-1). This method is simple, practical and can afford good precision and accuracy and can be successfully applied to assess aniline in water samples. A possible mechanism of the change of fluorescence intensity introduced by putting the aniline into the system is also discussed.     

Determination of proteins with tetracarboxy manganese(II) phthalocyanine by resonance light scattering technique

A novel method for the determination of proteins by using tetracarboxy manganese(II) phthalocyanine (MnC4Pc) as a resonance light scattering (RLS) probe has been developed. At pH 3.0 Britton-Robinson (B-R) buffer solution, the RLS intensity of MnC4Pc at 385 nm is greatly enhanced in the presence of proteins. The effects of pH, reaction time, concentration of MnC4Pc and interfering substances on the enhanced RLS intensity are investigated, respectively. Under optimal conditions, the linear ranges of the calibration curves are 0-2.00 microg mL(-1) for bovine serum albumin (BSA) and human serum albumin (HSA), 0.0-1.75 microg mL(-1) for human-IgG and ovalbumin, with a detection limit of 16.37 ng mL(-1) BSA, 17.62 ng mL(-1) HSA, 19.41 ng mL(-1) human-IgG and 20.72 ng mL(-1) ovalbumin. The method has been applied to the determination of total proteins in human serum samples collected from a hospital and the results are in good agreement with those reported by the hospital.     

Second-Derivative Spectrophotometric Determination of Trace Copper after Preconcentration with the Ion Pair of 2-Nitroso-1-Naphthol-4-Sulfonic Acid and Tetradecyldimethylbenzylammonium Chloride on Microcrystalline Naphthalene or a Column

Copper is quantitatively retained by 2-nitroso-1-naphthol-4-sulfonic acid and tetradecyldimethylbenzylammonium chloride on microcrystalline naphthalene in the pH range 7.1–10.7 from large volumes of aqueous solutions of various samples. After filtration, the solid mass consisting of a copper complex and naphthalene is dissolved with 5 mL of dimethylformamide, and the metal is determined by second-derivative spectrophotometry. The copper complex can alternatively be quantitatively adsorbed on tetradecyldimethylbenzylammonium–naphthalene adsorbent packed in a column and determined similarly. About 1.5 g of copper can be concentrated in a column from 300 mL of aqueous sample, where its concentration is as low as 5 ng/mL. The effects of pH, the volume of the aqueous phase, and interferences from a number of metal ions on the determination of copper have been studied in detail to optimize the conditions for its determination in standard alloys and biological samples.     

Determination of trace levels of manganese in various biological and environmental samples by atomic absorption spectrometry after solid-liquid extraction and preconcentration with the ion pair formed by the nitroso-S anion and the tetradecyldimethylbenzylammonium cation.

Manganese is quantitatively retained by 2-nitroso-1-naphthol-4-sulfonic acid (nitroso-S) and tetradecyldimethylbenzylammonium (TDBA) chloride on microcrystalline naphthalene in the pH range 9.5-10.6 from large volumes of aqueous solutions of various samples. After filtration, the solid mass consisting of the manganese complex and naphthalene is dissolved in 5 mL dimethylformamide and the metal is determined by flame atomic absorption spectrometry. Alternatively, the manganese complex can be quantitatively adsorbed on TDBA-naphthalene adsorbent packed in a column and determined similarly. About 0.2 microg manganese can be concentrated in a column from 400 mL aqueous sample with a concentration as low as 0.5 ng/mL. Eight replicate determinations of manganese at 0.8 microg/mL gave a mean absorbance of 0.156 for the final solution with a relative standard deviation of 1.4%. The sensitivity for 1% absorption was 23 ng/mL. The interference of a large number of anions and cations was studied, and the optimized conditions developed were used for trace determinations of manganese in various alloys, and in biological and environmental samples.     

Flame atomic absorption spectrometric determination of trace chromium in various standard samples after preconcentration with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

Chromium can be quantitatively retained as 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)-tetra-phenylborate(TPB) complex onto microcrystalline naphthalene in the pH range 4.8-5.9 from a large volume of aqueous solutions of various standard samples. After filtration, the solid mass consisting of the chromium complex and naphthalene was dissolved with 5 mL of dimethylformamide and the metal was determined by air-acetylene FAAS. A detection limit of 4 ng/mL for chromium was established. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the trace determination of chromium in various standard alloys and biological samples.     

Flame atomic absorption spectrometric determination of trace chromium in various standard samples after preconcentration with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

Chromium can be quantitatively retained as 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)-tetraphenylborate(TPB) complex onto microcrystalline naphthalene in the pH range 4.8–5.9 from a large volume of aqueous solutions of various standard samples. After filtration, the solid mass consisting of the chromium complex and naphthalene was dissolved with 5 mL of dimethylformamide and the metal was determined by air-acetylene FAAS. A detection limit of ¶4 ng/mL for chromium was established. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the trace determination of chromium in various standard alloys and biological samples.     

2‐Aminocyclopentene‐1‐Dithiocarboxylic Acid‐Naphthalene Adsorbent for the Preconcentration and Determination of a Trace Copper in Real Samples by Spectrophotometric Method

A solid uncharged complex produced from 2‐aminocyclopentene‐1‐dithiocarboxylic acid (synthetic reagent) on naphthalene provides a very sensitive, selective and economical method for the preconcentration and determination of trace amounts of copper in drug and alloy samples. The 2‐aminocyclopentene‐1‐dithiocarboxylate of copper is retained quantitatively on microcrystalline naphthalene in the pH range 2.8–3.3. After filtration the solid mass consisting of copper complex‐naphthalene is dissolved with 4 mL of dimethylformamide (DMF). The absorbance is measured at 462 nm with a spectrophotometer against the reagent blank and molar absorptivity found to be 2.8 × 10⁵ liter mol^?1 cm^?1. Beer's law is obeyed over the concentration range of 0.1–16.0 μg of copper in 4 mL of the dimethylformamide solution. Detection limit is 3 ng mL^?1 [signal to noise ratio = 2]. Ten replicate determinations on a sample containing 1 μg of copper gave a relative standard deviation of 0.76%. The interference of a large number of anions and cations have been studied and the optimized conditions developed were utilized for determination of copper in various real samples.     

微晶萘固液萃取分离和ICP-AES测定痕量金的研究

在一定酸度的盐酸介质中,络阴离子ＡｕＣｌ－４与孔雀绿（ＭＧ）形成稳定的离子缔合物,可被析出的微晶萘定量吸附,实现痕量金的分离与富集。分离了基体富集物中的Ａｕ,并用ＩＣＰ－ＡＥＳ测定。详细考察了影响金的分离与测定的各种因素。在优化的实验条件下,方法的检出限为６．０ｎｇ／ｍＬ,ＲＳＤ为１．３４％（ｎ＝９）。本法已用于矿石浸取液和标准矿样中痕量金的测定,分析结果满意。     

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…     

Spectrophotometric Determination of Ziram by Coprecipitating the Corresponding Copper(II) or Palladium(II) Complex with Naphthalene

A spectrophotometric method has been developed for the determination of zinc dimethyldithiocarbamate (ziram) by converting it into dimethyldithiocarbamate and coprecipitating its copper(II) and palladium(II) dimethyldithiocarbamate complexes and coprecipitating onto microcrystalline naphthalene. Palladium(II) and copper(II) complexes absorb strongly at 395 nm and 430 nm, respectively. The interference of various ions has been studied and the method has been applied to determine ziram in commercial samples and grains.     

Determination of proteins at nanogram levels by their quenching effect on the chemiluminscence reaction between luminol and hydrogen peroxide with manganese-tetrasulfonatophthalocyanine as a new catalyst

The manganese-tetrasulfonatophthalocyanine (MnTSPc) catalyzed luminol-hydrogen peroxide chemiluminescence (CL) systems can be quenched in the presence of proteins. A highly sensitive CL quenching method has been developed for the determination of proteins. Under optimum conditions, the linear ranges of the calibration curves were 0.1-20 microg/mL for human serum albumin (HSA), 0.2-20 microg/mL for human gamma-IgG, and 0.5-50 microg/mL for the bovine serum albumin (BSA) with the corresponding detection limits were 1.9 ng/mL, 2.7 ng/mL, and 3.4 ng/mL. The method has been applied to the analysis of total proteins in human serum samples and the results were in good agreement with clinical data provided.     

Preconcentration of copper with dithizone-naphthalene for subsequent determination by atomic absorption spectrometry

A simple and convenient method for the separation and preconcentration of copper from aqueous samples has been developed. The procedure is based on the chemical sorption of copper(II) onto a column packed with immobilized dithizone on microcrystalline naphthalene. The trapped copper is eluted with 10 mL of 4 M nitric acid and determined by flame atomic absorption spectrometry. A preconcentration factor of 200 was obtained for a volume of 2 L. The relative standard deviation for the determination of 5 and 10 μg/L copper was 2.2 and 1.7%, respectively. The procedure was successfully applied to the determination of copper in water and alloy samples. The accuracy was assessed through the analysis of certified reference materials or recovery experiments. The text was submitted by the authors in English.     

Differential pulse polarographic determination of uranium(VI) in complex materials after adsorption of its trifluoroethylxanthate cetyltrimethylammonium ion-associated complex on naphthalene adsorbent.

Uranium(VI) is adsorbed as a uranium trifluoroethylxanthate (TFEX)-cetyltrimethylammonium (CTMA) ion-pair complex on microcrystalline naphthalene quantitatively in the pH range 4.2 - 7.0. Without cetyltrimethylammonium as the counter ion, the adsorption is hardly 70%. The metal has been desorbed with HCI and determined with a differential pulse polarograph. Uranium can alternatively be quantitatively adsorbed on TFEX-CTMA-naphthalene adsorbent packed in a column at a flow rate of 1 - 5 ml/min and determined similarly. A well-defined peak has been obtained in this medium at -0.20 V versus a saturated calomel electrode. Cyclic voltammetry, differential pulse polarography and D.C. polarography studies indicate that uranium has been reduced irreversibly under these conditions. The detection limit is 0.30 microg/ml at the minimum instrumental settings (signal-to-noise ratio of 2) (with a preconcentration factor of 10, the detection limit would be 30 ng/ml for uranium when the volume in the cell is 15 ml). However if the volume in the cell is 5 ml, it would have been 10 ng/ml with a preconcentration factor of 30. Linearity is maintained in a concentration range of 0.5 - 19.0 microg/ml (2.1 - 79.83 x 10(-9) M) with a correlation factor of 0.9994 and a relative standard deviation of +/-1.1% (in this case 7.5 microg may be concentrated from 150 ml of the aqueous sample where its concentration is as low as 50 ng/ml). Various parameters, such as the effect of the pH, volume of the aqueous phase, flow rate and the interference of a large number of metal ions and anions on the determination of uranium, have been studied in detail to optimize the conditions for its trace determination in various complex materials, like alloys, coal fly ash, biological, synthetic, and waste-water samples.     

Determination of trace amounts of copper(II) by using catalytic redox reaction between methylene blue and ascorbic acid.

A sensitive and selective kinetic-spectrophotometric method is proposed for the determination of microg mL(-1) amounts of Cu2+ based on its catalytic effect on the oxidation of L-ascorbic acid by Methylene Blue in a strongly acidic medium. The reaction is monitored spectrophotometrically by measuring the decrease in color intensity of Methylene Blue at 665 nm. The analysis of Cu2+ ion is performed by a fixed-time method. At a given time of 2 min at pH 2.20 and 32 degrees C, the detection limit is 10 ng mL(-1) and the relative standard deviation for 0.4 microg mL(-1) Cu2+ is 3.60% (n = 6). The method is free from most of the interferences and the effect of diverse ions on the determination of Cu2+ is also reported. The proposed method is virtually specific to copper and has been satisfactorily applied to its determination in electric copper wire samples and pharmaceutical products. Results were also verified by the atomic absorption spectrometry technique (AAS).     

Atomic absorption spectrometric determination of trace amounts of nickel after preconcentration with [1-(2-Pyridylazo)-2-Naphthol]-Naphthalene adsorbent or after adsorption of its complex on microcrystalline naphthalene

An atomic absorption spectrometric method for the determination of trace amounts of nickel after adsorption of its 1 -(2-pyridylazo)-2-naphthol complex on microcrystalline naphthalene has been developed. This complex is adsorbed on microcrystalline naphthalene in the pH range 4.5-7.8 from large volumes of aque ous solutions of various alloys and biological and environmental samples containing nickel. After filtration, the solid mass consisting of nickel complex and naphthalene was dissolved in 5 mL of dimethylformamide, and the metal was determined using a flame atomic absorption spectrometer at a wavelength of 232 nm. Alternatively, nickel can be quantitatively adsorbed on [l-(2-pyridylazo)-2-naphthol]-naphthalene adsorbent packed in a column and determined similarly. The calibration curve is linear over the concentration range 2.0-100 Μg of nickel in 5 mL of the final dimethylformamide solution. Eight replicate determinations of 20 Μg of nickel give a mean absorbance of 0.072 with a relative standard deviation of 1.3%. The sensitivity for 1% absorption is 0.24 Μg/mL. Various parameters such as the effect of pH, the volume of the aqueous phase, and the interference of a large number of metal ions with the determination of nickel have been studied in detail to optimize the conditions for its determination in various standard alloys and biological and environmental samples. This article was submitted by the authors in English.     

Separation and determination of trace amounts of aluminium(III), vanadium(V), iron(III), copper(II) and nickel(II) with CALKS and PAR by RP-HPLC.

An RP-HPLC method for the separation and determination of aluminium(III), vanadium(V), iron(III), copper(II) and nickel(II) with CALKS (Chromazol KS) and PAR ([4-(2-pyridylazo)resorcinol]) chelating on a YWG-ODS column was developed. A mixture of methanol-tetrahydrofuran(THF)-water (60:5:35 v/v) containing 0.2 mol/L LiCl, 5 x 10(-5) mol/L CALKS, 5 x 10(-5) mol/L PAR and acetate buffer solution (pH 4.9) was selected as mobile phase. The method has high sensitivity, with the detection limits being 6 ng/mL for aluminium(III), 3.5 ng/mL for vanadium(V), 10.4 ng/mL for iron(III), 6.3 ng/mL for copper(II) and 8.7 ng/mL for nickel(II). It also has good selectivity, so that most foreign metal ions do not interfere under the optimum conditions. The method can be applied to the simultaneous determination of trace amounts of aluminium, vanadium, iron, copper and nickel in rice and flour samples.     

Differential pulse polarographic determination of lead in complex materials after adsorption of its N-methylethylxanthocarbamate complex on microcrystalline naphthalene or on N-methylethylxanthocarbamate-benzyldimethyltetradecylammonium-naphthalene adsorbent

Lead is quantitatively adsorbed as the lead N-methylethylxanthocarbamate (MEXC)-benzyldimethyltetradecylammonium (BDTA) ion pair complex on microcrystalline naphthalene in the pH range 4.0-11.0. The metal is desorbed with HCI and determined by differential pulse polarography. Alternatively lead can be quantitatively adsorbed on the adsorbent (MEXC-BDTA-naphthalene) packed in a column at a flow rate of 1-2 mL/min and determined similarly. Dissolved oxygen is removed by adding a few milliliters of 4% NaBH4 solution. The detection limit is 0.12 microg/mL at the minimum instrumental settings (signal-to-noise ratio, 2). Linearity was obtained over the concentration range 0.3-20.0 microg/mL with a correlation factor of 0.9998 and a relative standard deviation of +/- 0.98%. Various parameters, such as the effect of pH, volume of aqueous phase, flow rate, and the interference of a large number of metal ions and anions, were studied in detail to optimize the conditions for the trace determination of lead in various standard alloys, standard biological materials, and environmental samples.     

Simultaneous determination and pharmacokinetic studies on (3,4-Dihydroxyphenyl)-lactic acid and protocatechuic aldehyde in rat serum after oral administration of Radix Salviae miltiorrhizae extract

A simple and sensitive high-performance liquid chromatography method is developed for the simultaneous determination of (3,4-dihydroxyphenyl)-lactic acid (Dhpl) and protocatechuic aldehyde (Pal) in rat serum after oral administration of Radix Salviae miltiorrhizae extract. Serum samples are acidified with hydrochloric acid and extracted with ethyl acetate. Analysis of the extract is performed on a reversed-phase column and a mobile phase of 0.02% phosphoric acid-acetonitrile (91:9, v/v) with UV detection at 280 nm. Standard curves are linear in the range of 1.47-456.96 microg/mL for Dhpl and 0.124-7.936 microg/mL for Pal. For both regression coefficients, r(2) is greater than 0.993. Mean recovery is determined to be 75.23% and 84.06%, respectively, by analyzing serum standard containing 7.14, 57.12, and 228.48 microg/mL of Dhpl and 0.124, 0.992, and 3.968 microg/mL of Pal. The intraday precision (relative standard deviation) ranges from 3.91% to 12.03% at concentrations of 1.43, 57.12, and 228.48 microg/mL for Dhpl and 3.79% to 8.12% at concentrations of 0.124, 0.992, and 3.968 microg/mL for Pal. The interday precision (relative standard deviation) ranges from 5.06% to 9.93% for Dhpl and 3.05% to 10.00% for Pal, respectively, at the same three concentrations. This validated assay is applied to the determination of Dhpl and Pal concentrations and used to take a limited view of the pharmacokinetic profile in rat serum after oral administration of Radix Salviae miltiorrhizae extract.