Spectrophotometric Simultaneous Determination of Zinc(II), Manganese(II) and Iron(II) in Pharmaceutical Preparations Using OSC-PLS

The purpose of this paper is to develop a fast and sensitive spectrophotometric method for the simultaneous determination of zinc(II), manganese(II) and iron(II) in pharmaceutical preparations. The method presented in this work is based on the well-known reaction of these ions with 4-(pyridylazo)resorcinol (PAR)1. The application of quantitative chemometric methods, particularly PLS to multivariate chemical data is becoming more widespread owing to the availability of digitized spectroscop…     

Simultaneous Spectrophotometric Determination of Trace Palladium and Rhodium with2，4－TADAT

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Flow Injection On‐line Preconcentration Coupled with Hydride Generation Atomic Fluorescence Spectrometry for Ultra‐Trace Amounts of Bismuth Determination in Biological and Environmental Water Samples

Abstract

A simple and sensitive flow injection on line separation and preconcentration system coupled to hydride generation atomic fluorescence spectrometry (HG‐AFS) was developed for ultra‐trace bismuth determination in water and urine samples. The preconcentration of bismuth on a nylon fiber‐packed microcolumn was carried out based on the retention of bismuth complex with Bismuthiol I. A 15% (v/v) HCl was introduced to elute the retained analyte complex and merge with KBH₄ solution for HG‐AFS detection. Under the optimal experimental conditions, an enhancement factor of 20 was obtained at a sample frequency of 24/h with a sample consumption of 13.0 ml. The limit of detection was 2.8 ng/l and the precision (RSD) for 11 replicate measurements of 0.1 µg/l Bi was 4.4%.     

A Solid‐phase Spectrophotofluorimetry for the Determination of Trace Amount of Nitrite in Food Samples with Rhodamine B

Abstract

A simple and sensitive solid‐phase fluorescence quenching method for the determination of trace amounts of nitrite in food samples has been developed. The method is based on that rhodamine B (RhB) which is used as an emission reagent and is included by β‐cyclodextrin polymer(β‐CDP), reacts with nitrite in the presence of iodide to form a nonfluorescence compound in acidic medium. The fluorescence intensity of the RhB‐included β‐CDP was measured in solid phase with excitation and emission wavelengths of 353 and 592 nm, respectively. The fluorescence quenching degree is good linear with the concentration of nitrite over the ranges of 1.0–3.0 µg with a detection limit of 0.04 µg and RSD is 1.2%. The general coexisting ions do not interfere to the reaction of RhB with nitrite. The proposed method has been applied to the determination of trace amount of nitrite in food samples with the recoveries of 102.8% (ham) and 99.0% (sausage), respectively.     

Spectrophotometric Determination of Zinc in Pharmaceutical and Biological Samples with Di‐2‐pyridyl Ketone Benzoylhydrazone: a Simple,Fast, Accurate and Sensitive Method

Abstract

A simple, fast, accurate, and sensitive spectrophotometric method was developed to determine zinc(II). This method is based on the reaction of Zn(II) with di‐2‐pyridyl ketone benzoylhydrazone (DPKBH), at pH=5.5 and 50% (v/v) ethanol. Bee?s law was obeyed in the range 0.020–1.82 µg mL^?1 with a molar apsorptivity of 3.64×10⁴ L mol^?1 cm^?1, and a detection limit (3δ) of 2.29 µg L^?1. The action of some interfering ions was verified and the developed method applied to pharmaceutical and biological samples. The results were then compared with those obtained by using a flame atomic absorption technique.     

Spectrophotometric Determination of Nitrite in Water Samples with 4‐(1‐Methyl‐1‐Mesitylcyclobutane‐3‐yl)‐2‐Aminothiazole

Abstract

A simple, sensitive, and specific spectrophotometric method for the measurement of nitrite in water has been developed and optimum reaction conditions along with other analytical parameters have been evaluated. The azo dye, 4‐(1‐methyl‐1‐mesitylcylobutane‐3‐yl)‐2‐(p‐N,N‐dimethylazobenzene)‐1,3‐thiazole was synthesized with the reaction of 4‐(1‐methyl‐1‐mesitylcylobutane‐3‐yl)‐2‐aminothiazole and N,N‐dimethyl aniline in acidic medium. Obtained azo dye has been characterized by infrared (IR), ¹H nuclear magnetic resonance (NMR), and microanalysis methods. The dye shows an absorption maximum at 482 nm. The method is optimized for acid concentration, pH, amount of reagents required, time, and interfering species. All the determinations were carried out at this wavelength throughout the work. At an analytical wavelength of 482 nm, Beer's law is obeyed over the concentration range 0.05 to 2.00 µg nitrite per mL analyte. The molar absorptivity, Sandell's sensitivity, and relative standard deviation are 2.03×10⁴ L mol^?1 cm^?1±251.3 (95%), 2.28×10^?3 µg cm^?2, and 2.74% (n=10), respectively. The detection limit of the method is 0.012 µg ml^?1 of nitrite ion. The method was succesfully applied to the determination of nitrite in tap water and lake water.     

Indirect Determination of CTMAB with Sodium Chloride and Ammonium Thiocyanate by Floatation and Separation of Zinc

Cetyl-trimethylammoniumbromide(CTMAB)isaveryusefulcationicsurfactant,sothestudyondeterminationofCTMABassumesgreatimportance.AsmallamountofCTMABisgenerallydeterminedbyspectrophotometrybasingCTMABcombineswithtriazidetoformcoloredbinaryion-associationcomplex1-3.However,thosemethodsofdeterminationofCTMABhavedisadvantagesofsmalllinearrange,needofspecialreagent,determinationinbaseenvironment,etc.Inthispaper,indirectdeterminationofCTMABwithNaClandNH4SCNbyfloatationandseparationofZn(II…     

Determination of Iridium in Environmental and Geological Samples by NAA with α-Amino Pyridine Resin Preconcentration

The Ir, Au and Pd concentrations in three certified reference materials SARM-7, FC-1 and DZ-1 were determined by neutron activation analysis using -amino pyridine preconcentration. Good agreement between the reference values and our results was obtained, and the reliability of our method was confirmed. This method is suitable for ppb or sub-ppb levels of Ir and Au analyses in environmental and geological samples. The Ir and Au levels in a Chinese coastal sediment GBW07314 were also analyzed.     

Thermodynamics of Copper(II), Zinc(II), Cobalt(II), Mercury(II), and Nickel(II) Complexation with α,α-Dipyrrolylmethene in DMF

Thermodynamics of complexation reactions between Zn(II), Ni(II), Hg(II), Co(II), and Cu(II) acetates and 3,35,5-tetramethyl-4,4-dibutyldipyrrolylmethene in DMF at 298.15 K is studied by calorimetric and spectrophotometric methods. The replacement of Zn²⁺, Ni²⁺, and Hg²⁺ ions by Co²⁺ and Cu²⁺ ions was found to increase the equilibrium constants of reactions of complex formation with dipyrrolylmethene by more than two orders of magnitude. The role of solvation interactions in coordination of dipyrrolylmethene by d-metal ions is established.     

Procaine as a Sensing Material for Determination of Dysprosium(III) Ions in Presence of Other Rare‐earth Elements in Biological and Environmental Samples

Abstract

The biological properties of the lanthanides, primarily based on their similarity to calcium, have been the basis for research into potential therapeutic applications of lanthanides since the early part of the twentieth century. In this research, procaine was used as a sensing material in construction of a new Dy(III) potentiometric membrane sensor. The sensor exhibits a Nernstian response over a concentration range of 1.0×10^?6 mol l^?1?1.0×10^?1 mol l^?1, with a detection limit of 7.9×10^?7 mol L^?1. The best performance was achieved with a membrane composition, consisting of 30% PVC, 63% dibutylphthalate (DBP), 5% procaine and 2% sodium tetraphenylborate (NaTPB). It was found that at the pH range of 4.0–8.0, the potential response of the sensor was not affected by the pH. Furthermore, the electrode presents satisfactory reproducibility, very fast response time (<10 s) and relatively good discriminating ability for Dy(III) ions with respect to many common cations and other lanthanide ions. The sensor has been applied to the determination of Dy(III) in human serum and in soil and sediment samples. Validation with Certified Reference Material (CRM) was also done.     

Separation and Removal of Mercury(II) from Water Samples Using (Acetylacetone)‐2‐Thiol‐Phenyleneimine Immobilized on Anion‐Exchange Resin Prior to Determination by Cold Vapor Inductively Coupled Plasma Atomic Emission Spectroscopy

Abstract

(Acetylacetone)‐2‐thiol‐phenyleneimine (H₂L) immobilized on an anion‐exchange resin (Dowex) was used for separation and removal of mercury from natural water samples and for preconcentration prior to its determination by cold vapor inductively coupled plasma atomic emission spectroscopy. The metal was eluted from the column using a solution of 10% thiourea in 0.1 M HCl. The modified resin is higly selective with an exchange capacity of 1.60 mmol g^?1. Various parameters like pH, column flow rate, and desorbing agents are optimized. The proposed method has a linear calibration range of 15–1000 ng/ml Hg(II), with a relative standard deviation at the 15 ng/ml level of 3.5%. The precision of the method (evaluated as the relative standard deviation obtained after analyzing six series of five replicates) was ±4.2% at the 50 ng/ml level of Hg(II). The method has been used for routine determination of trace levels of mercury species in natural waters. The potential application of modified resin for the removal of mercury(II) from two natural water samples (top water and lake water) spiked with 50 ng/ml of mercury (II) was studied by ICP‐AES, and the results proved that excellent percent extraction of mercury(II) from both natural water samples was obtained by column method using modified resin.     

Simultaneous Determination of Chromium Species in Water and Plant Samples at Trace Levels by Ion Chromatography–Inductively Coupled Plasma-Mass Spectrometry

Ion chromatography–inductively coupled plasma-mass spectrometry (IC–ICP-MS) was used for the identification and quantification of chromium species. Chromium(III) and chromium(VI) were separated and determined by IC–ICP-MS. The separation was achieved using an anion exchange column with 0.55?M HNO₃ as mobile phase. It was a particular goal of this work to exclusively use nitric acid for elution in order to reduce interferences in the ICP-MS system. Analytical figures of merit were calculated under the optimum conditions by developing calibration plots in a concentration range of 0.50–250?µg/L for both species. The detection limits for Cr(III) and Cr(VI) were 0.09 and 0.03?µg/L, respectively. Spiked recovery tests were used to evaluate the applicability of the analytical method in environmental samples, and the recoveries ranged between 97 and 103% for both analytes. The accuracy of the method for total chromium content was validated through the analysis of a spring water-certified reference material (UME 1201), and the obtained results were in good agreement with the certified value. Lettuce seedlings were cultivated to evaluate the intake levels of these species. In addition, the bioaccessibility of Cr(III) and Cr(VI) from the lettuce seedlings in simulated gastric and intestinal fluids media was examined.     

Simultaneous Determination of Cadmium,Mercury, Lead,Arsenic, Copper,and Zinc in Human Breast Milk by ICP‐MS/Microwave Digestion

Abstract

An analytical method using microwave digestion and inductively coupled argon plasma-mass spectrometry (ICP‐MS) analysis was developed for the measurement of Cd, Hg, Pb, As, Cu, and Zn in human breast milk. We applied external calibration, internal calibration, and standard addition for reference material and pooled milk analysis. Method performances were defined in terms of detection limits, accuracy, and precision. Accuracy varied between 93% and 105% and precision between 3% and 8%. External calibration and background interferences were checked through a calibrator addition procedure. Our method has shown high accuracy, precision, and sensitivity, as well as linearity within a wide range of values. Our methodology, developed by treatment of reference material and pooled milk samples, was applied for determination of Cu, Zn, As, Cd, Hg, and Pb in 120 human breast milk samples.     

Spectrophotometric Determination of Gold in Water and Ore with 2‐Carboxyl‐1‐Naphthalthiorhodanine

Abstract

This paper reports on the synthesis of a new chromogenic reagent, 2‐carboxyl‐1‐naphthalthiorhodanine (CNTR). A high sensitive, selective, and rapid method for the determination of gold based on the rapid reaction of gold with CNTR and the solid phase extraction of the colored chelate with a reversed phase polymer‐based C₁₈ cartridge was developed. In the presence of 0.05–0.5 mol L^?1 of phosphoric acid solution and emulsifier‐OP medium, CNTR reacts with gold to form a red chelate of a molar ratio 1∶3 (gold to CNTR). This chelate was enriched by the solid phase extraction with a polymer‐based C₁₈ cartridge and the retained chelate was eluted from the cartridge with dimethyl formamide (DMF). The enrichment factor of 100 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.35×10⁵ L · mol^?1 · cm^?1 at 540 nm. Beer's law is obeyed in the range of 0.01～2 µg mL^?1 in the measured solution. The relative standard deviation for 11 replicates sample of 0.5 µg L^?1 level is 2.05%. The detection limit, based on three times the standard deviation is 0.02 µg L^?1 in the original sample. This method was applied to the determination of gold in water and ore with good results.     

Microwave‐Assisted Dehalogenation of α‐Haloketones by Zinc and Ammonium Chloride in Alcohol

The treatment of α‐haloketones with 1.5 equiv. of Zn and 1 equiv. of NH₄Cl in ethanol for 0.5 min gave the corresponding ketones with excellent yields under microwave irradiation. Vic‐dibromides and 2,2‐dibromoacetophenone can be efficiently debrominated to alkenes and acetophenones, respectively.     

New Synthesis of 2H‐3,1‐Benzoxazine Derivatives: Zinc Chloride–Catalyzed Cyclocondensation of 2‐Amino‐5‐nitrobenzonitrile with Aldehydes under Microwave Conditions

2H‐3,1‐Benzoxazine derivatives were prepared in good yields from 2‐amino‐5‐nitrobenzonitrile and aldehydes in the presence of anhydrous zinc chloride under microwave irradiation conditions.     

Simultaneous Determination of Gold(Ⅲ) and Copper(Ⅱ) with Two-Way Stripping Voltammetry

The simultaneous determination of Au(Ⅲ) and Cu(Ⅱ) by atomic absorption spectrometry^[1,2], X-ray fluorescence^[3] and differential-pulse polarography^[4] have been reported. The apparatus used in spectrochemical analysis are complex and expensive. The method reported in reference^[4] involves a poisonous electrode-DME(dropping-mercury electrode) and unsatisfied performance with the detection limit. We had reported the determination of trace Au(Ⅲ) or Cu(Ⅱ) by a sensitive tripping voltammetry with solid electrode^[5], but there is no report about the simultaneous determination of trace Au(Ⅲ) and Cu(Ⅱ) by stripping voltammetry ever since.     

Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aqueous Solution

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Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aquesous Solution

A selective and sensitive method for determination of platinum and palladium(Ⅱ）in an aqueous solution simultaneously by laser thermal lens spectrometry,based on the complex reaction of 2-(3,5-dichloropyridylazo)-5-dimethylaminoamiline(3,5-diCl-PADMA) with platinum and palladium,has been developed.It is shown that the palladium complex can be fromed at room temperature, while the platinum complex can be only formed after being heated in a boiling water bath.By using this difference of reaction temperature and the characteristic of the complexes mentioned above,the method for simultaneous determination of platinum and palladium was established in an aqueous solution without a pre-separation.The results show that the dynamic linear ranges of determination for platinum and palladium are 0.005-0.04μg/mL and 0.005-0.25μg/mL respectively,and that the detection limits are both 0.002/μg/mL.The method has been applied to the determination of platinum and palladium simultaneously in alloy and catalyst samples with satisfactory results.     

Kinetic Spectrophotometric Determination of Traces of Manganese(II) by Its Catalytic Effect on Oxidation of 4‐Hydroxycoumarin with Potassium Permanganate in River Water Samples

Abstract

A new kinetic method for determination of traces of manganese(II) based on its catalytic effect on the oxidation of 4‐hydroxycoumarine with KMnO₄ at pH=1.35 and at a temperature of 25°C was proposed. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of the dye at 525 nm. The calibration graph is linear in the range 20–200 ng/cm³. The effects of certain foreign ions upon the reaction rate were determined for assessment by the selectivity of the method. The proposed method has been applied for determination of manganese(II) in river water samples with satisfactory results.