A New and Highly Sensitive Spectrophotometric Determination of Monocrotophos in Environmental,Agricultural and Biological Samples

A new and highly sensitive spectophotometric method is developed for the determination of parts per million levels of widely used organophosphorus pesticide monocrotophos. The method is based on alkaline hydrolysis of monocrotophos to N‐methylacetoacetamide followed by coupling with diazotized p‐amino acetophenone in alkaline medium. The absorption maxima of the reddish‐violet coloured compound formed is measured at 560 nm. Beer's law is obeyed over the concentration range of 1.2 to 6.8 μg in a final solution volume of 25 mL. The molar absorptivity and Sandell's sensitivity were found to be 7.1 × 10⁵ (±100) L mole^?1 cm^?1 and 0.008 μg cm^?2, respectively. The standard deviation and relative standard deviation were found to be ± 0.005 and 2.05%, respectively. The method is simple, sensitive and free from interferences of other pesticides and diverse ions. The method has been satisfactorily applied to the determination of monocrotophos in environmental, agricultural and biological samples.     

Spectrophotometric Determination of Trace Chromium(VI) in Mass Chromium(III)

There is little conclusive evidence of the toxic effects of Cr(III) so far, but Cr(VI) has carcinogenic activity, so the analysis of the chromine ions is very important in environmental research and the quality control of industry products. Usually Cr(III) and Cr(VI) interfere with each other in the species analysis, the measurement of Cr(VI) of numerous previous papers is related to the Cr(VI) samples, which contain a little Cr(III). When the amount of trivalent chromine exceeds ten …     

Synthesis of New Reagent Benzyloxybenzaldehydethiosemicarbazone (BBTSC): Selective,Sensitive and Extractive Spectrophotometric Determination of Pd(II) in Water Samples and Synthetic Mixtures

A new reagent, benzyloxybenzaldehydethiosemicarbazone (BBTSC) was synthesized and a new method was developed for the simple, highly selective and extractive spectrophotometric determination of palladium(II) with BBTSC at wave length 365 nm. The metal ion formed a yellow colored complex with BBTSC in acetate buffer of pH 5.0, which was easily extractable into cyclohexanol with 1:1 (Metal: Ligand) composition. The method obeys Beer's law in the range of 5–60 ppm. The molar absorptivity and Sandell's sensitivity were found to be 0.4 × 10⁴ Lt. mol^?1 cm^?1 and 0.02661 μg cm^?2, respectively. The correlation co‐efficient of the Pd(II)‐BBTSC complex was 0.9657, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) (n = 10), which was 0.321% and its detection limit 0.016875 μg.mL^?1. The instability constant of the method was calculated by Asmus' method as 3.5714 × 10^?4. The interfering effect of various cations and anions were also studied. The proposed method was successfully applied for the determination of palladium(II) in synthetic and water samples. The results were compared with those obtained using an atomic absorption spectrophotometer, testing the validity of the method.     

Sensitive Spectrophotometric Determination of Vanadium in Environmental Samples at PPB Levels

Abstract

A new, sensitive and selective method for separation, and extraction - spectrophotometric determination of V (V) with pyrogallol {Ar (OH)₃} and hydroxyamidines (HOA) is described. The molar absorptivities of the colored species with six substituted HOA lie in the range of (0.52–1.5)x 10⁶ L mole^?1 cm^?1 at λ_max 430–440 nm. Of these, the simplest compound, N-hydroxy-N, N- diphenylbenz-amidine (HDPBA) gives the most sensitive color reaction and hence, it is used for detailed studies. No interference of almost all diverse ions tested is noticed. The method offers the determination of vanadium in different environmental samples.     

Spectrophotometric Determination of Trace Amounts of Titanium in Geochemical and Metallurgical Samples

Abstract

The reaction between cyclohexan-1,2-dione bissalicyloylhydrazone and titanium(IV) has been studied spectrophotometrically. An orange complex (λ = 470 nm, ? = 1.49 × 10⁴ 1.mol^?1.cm^?1) is quickly formed at pH 1–2.5 in a 3+2 V/V ethanol/water medium. Interferences (more than 65 species) have been investigated. In presence of some masking agents most of metal ions do not interfere. The orange complex has been satisfactorily used for the determination of titanium in amphibolites, granites, suspended matter, Portland cement, bauxite, cast iron and duraluminium alloy. The results are compared with those obtained using AAS and ICP methods.     

Spectrophotometric Determination of U(VI) with Rifampicin in Soil Samples

A validated spectrophotometric method has been developed for the determination of uranyl ion in soil samples. The method is based on the complexation reaction between uranyl ion and rifampicin in methanol‐water medium at room temperature. The method is followed spectrophotometrically by measuring the absorbance at 375 nm. Under the optimized experimental conditions, Beer's law is obeyed in the concentration range of 1.35–20.25 μg mL^‐1 with apparent molar absorptivity and Sandell's sensitivity of 8.0 × 10³ L mol^‐1cm^‐1 and 0.042 μg/cm²/0.001 absorbance unit, respectively. The interference of a large number of anions and cations has been investigated and the optimized conditions developed have been utilized for the determination of uranium(VI) in soil samples. The three sigma detection limit (n = 9) for uranyl ion was found to be 0.20 μg mL^‐1. The proposed method was successfully applied to the determination of uranyl ion in soil samples.     

Spectrophotometric Determination of Copper in Natural Waters and Pharmaceutical Samples with Chloro(Phenyl) Glyoxime

A simple method for the determination of trace amounts of copper by spectrophotometry is described based on the formation of the copper‐chloro‐(phenyl) glyoxime complex. The molar absorptivities of the complexes at pH 4.0 at 290.5 nm were 0.8 × 10⁴l/mol cm. Optimal conditions such as reagent amounts and pH for the copper determination were reported. The effects of the foreign ions were also investigated. The method was successfully applied for determinations of copper in some natural waters and pharmaceutical samples.     

Direct Spectrophotometric Determination of Trace Cadmium(II) in Food Samples with 2-Acetylmercaptophenyldiazoaminoazobenzene (AMPDAA)

A novel chromogenic reagent, 2-acetylmercaptophenyldiazoaminoazobenzene (AMPDAA), has been prepared by coupling 2-aminoacetylthiophenol to 4-aminoazobenzene through the –NH–N=N– group. In the presence of TritonX-100, AMPDAA reacts with Cd(II) in 1:1 triethanolamine medium to form a red complex with maximum absorption at 529nm. Under the optimal conditions, Beers law is obeyed over the range of 0.0 to 1.0µgmL^–1 Cd(II), and the apparent molar absorptivity is 2.4× 10⁵Lmol^–1cm^–1. Based on this, a highly sensitive and selective spectrophotometric method has been developed for direct determination of trace cadmium. The detection limit and the quantification limit were found to be 6.5 and 9.7µgL^–1, respectively. The absorbance of AMPDAA-Cd(II) complex was 0.1881± 7.5×10^–3 with a 4.9% relative standard deviation for five repeated measurements of the sample containing 2µg of cadmium in 25mL solution under the same experimental conditions. Interference of foreign ions was also investigated. Except for Ag(I) and Hg(II), most foreign ions can be tolerated in considerable amounts. Interference caused by Ag(I) and Hg(II) can be reduced by adding sodium thiosulfate. The proposed method has been applied to the determination of trace cadmium in rice, grain and flour samples with satisfactory results.     

电感耦合等离子体质谱(ICP-MS)法测定农产品样品中6种痕量元素

建立了电感耦合等离子体质谱(ICP-MS)法测定果蔬类、大米等农产品样品中痕量元素的方法.样品通过HNO3-H2 O2混酸体系微波消解,以Rh作为内标溶液消除基体干扰,在仪器最佳条件下测定植物样中镉、铅、铬、铜、镍、锌6种痕量元素.方法的检出限为0.002～0.5μg/g;相对标准偏差(RSD)为0.84％ ～7.4％...     

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.     

环境样品中痕量邻苯二甲酸酯的分离与测定

本文研究了以小粒径（１０－４０μ）硅胶柱色谱分离富集、反相高效相色谱分析测定大气颗粒物、土主植物样品中痕量邻苯二甲酸酯的方法，方法操作简单，回收率高，空白值低，利用该方法分析了部分环境样品中邻苯二甲酯酯含量。     

Flow Injection Spectrophotometric Determination of Iodide in Environmental Samples

 An alternative and simple flow injection spectrophotometric analysis method for the determination of iodide in environmental samples is reported. The method is based on the catalytic destruction of the colour of the Fe(III)–SCN⁻–CP⁺–_nBP_y quarternary complex. The complex shows maximum absorption at 495 nm. The apparent molar absorptivity of the complex in terms of iodide is (6.22) × 10⁵ l mol⁻¹ cm⁻¹. The detection limit of the method is 0.1 ng ml⁻¹ of iodide. The method obeys Beer’s law up to 120 μg l⁻¹ with slope, intercept and correlation coefficient of 0.11, − 0.52 and + 0.99, respectively. Various flow injection analysis parameters for the determination of iodide in the environmental samples were optimized. The sample throughput of the method is 60 samples h⁻¹. The method was successfully useful for the determination of trace level of iodide in environmental samples i.e. ground, surface water. Received November 12, 2001; accepted April 2, 2002; published online July 22, 2002     

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.     

PVC膜修饰电极直接测定痕量聚氧乙烯类非离子表面活性剂

研究了一种新的PVC膜修饰电极微分脉冲伏安法直接测定痕量聚氧乙烯类非离子表面活性剂(PENS)的方法。由硫酸铜和四苯硼钠制得的配合物为活性物制成的PVC膜修饰电极在0.1mol/L NaOH溶液中对PENS有良好的选择性,-0.436V处出现1个灵敏的氧化峰。在最佳实验条件下,峰电流的降低与AEO9、AEO6、AEO3、TX-10分别在1.11×10-2~0.21nmol/L、4.34×10-2~64nmol/L、20.8nmol/L~4.1μmol/L、6.77×10-2~0.21nmol/L范围内有很好的线性关系,检出限分别为5.54×10-3、4.38×10-3、2.12、4.42×10-2nmol/L。该电极性能稳定,在AEO9浓度分别为0.16nmol/L和0.21nmol/L时,进行DPV测量(n=9),相对标准偏差分别为2.03%和1.97%。考察了环境水样中常见的共存离子对PENS测定的影响,结果表明大多数共存离子都有较高的允许量。PVC膜修饰电极的灵敏度高、选择性好、线性范围宽,不需预先分离,可直接用于环境水样中PENS含量的测定。     

A Sensitive Colorimetric Method for the Determination of Arsenic in Environmental and Biological Samples

Results of a thorough study and application of leucocrystal violet for the determination of arsenic in parts per million (ppm) levels in environmental and biological samples is described here. The proposed method is based on the reaction of arsenic with potassium iodate to liberate iodine. The liberated iodine selectively oxidises leucocrystal violet to form crystal violet dye in the presence of sodium hydroxide. The dye formed shows maximum absorbance at 592 nm. The detection limit of arsenic is 0.002 μgmL^?1 and the method obeys Beer's law over the concentration range of 0.1 μg - 1.0 μg of per 25 mL of final solution (0.004–0.04 ppm). The molar absorptivity was found to be 1.49 × 10⁶ L mol^?1 cm^?1. The proposed method was successfully applied for the determination of arsenic in various environmental and biological samples. The results are in good agreement with the standard reported method.     

溶剂浮选分离-紫外分光光度法测定环境水样中罗红霉素残留量

采用溶剂浮选法分离富集环境水样中罗红霉素,并利用紫外分光光度法对罗红霉素进行测定。罗红霉素的最佳浮选条件为在磷酸氢二钾溶液中,以异丙醇作浮选溶剂,控制溶液pH为9.0,氮气流量15mL·min~(-1),浮选时间30min。罗红霉素的质量浓度在8.2～40.2mg·L~(-1)范围内与其吸光度呈线性关系,检出限(3S/N)为0.26mg·L~(-1)。在河水及湖水样品中分别加入3个浓度水平的罗红霉素标准溶液做方法的回收试验,测得平均回收率均超过90%。     

A Robust Flow-Based System for the Spectrophotometric Determination of Cr(VI) in Recreational Waters

A flow-based method for the spectrophotometric determination of chromium (VI) in recreational waters with different salinities was developed. Chromium can occur in the environment in different oxidation states with different related physiological properties. With regard to chromium, the speciation is particularly important, as the hexavalent chromium is considered to be carcinogenic. To achieve that purpose, the use of the diphenylcarbazide (DPC) selective colored reaction with the hexavalent chromium was the chosen strategy. The main objective was to develop a direct and simple spectrophotometric method that could cope with the analysis of different types of environmental waters, within different salinity ranges (fresh to marine waters). The potential interference of metal ions, that can usually be present in environmental waters, was assessed and no significant interferences were observed (<10%). For a complete Cr(VI) determination (three replicas) cycle, the corresponding reagents consumption was 75 µg of DPC, 9 mg of ethanol and 54 mg of sulfuric acid. Each cycle takes about 5 min, including the system clean-up. The limit of detection was 6.9 and 12.2 µg L⁻¹ for waters with low and high salt content, respectively. The method was applied for the quantification of chromium (VI) in both fresh and marine water, and the results were in agreement with the reference procedure.     

Determination of Hg(II) in Environmental Water Samples by Dispersive Liquid Phase Microextraction Combined with Flame Atomic Absorption Spectrometry

In this study, a method of dispersive liquid phase microextraction combined with the flame atomic absorption spectrometry was proposed for the determination of trace Hg using diphenylthiocarbazone as chelating reagent. Several factors which have effect on the microextraction efficiency of Hg, such as pH, extraction and dispersive solvent type and their volume, concentration of the chelating agent, extraction time were investigated, and the optimized experimental conditions were established. After extraction, the enrichment factor was 68. The detection limit of the method was 45 ng mL^?1, and the relative standard deviation for eight determinations of 2 μg mL^?1 Hg was 1.7%. The results for the determination of Hg in environmental water samples (tap water, well water, mineral water and Caspian sea water) have demonstrated the applicability of the proposed method.     

顺序注射-化学发光法测定环境水样中痕量乐果

基于在盐酸溶液中,乐果在氢氧化钠介质中的水解产物被铈(Ⅳ)氧化而产生强烈的化学发光,并结合应用顺序注射技术,提出了SI-CL法测定环境水样中痕量乐果的方法。采用三区带进样模式,将试剂按以下方式组合:(a)0.3mol·L-1氢氧化钠溶液与8g·L-1 HPC溶液混合,(b)水样及(c)0.035mol·L-1硫酸铈铵溶液与1.2mol·L-1盐酸溶液混合。其进样体积依次为(a)200μL,(b)200μL和(c)80μL。化学发光强度与乐果的质量浓度在1~100μg·L-1和100~800μg·L-1两个范围内呈线性关系。检出限(3σ)为0.17μg·L-1。回收率在85.7%~119%之间。     

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.