Non-destructive method for the analysis of gold(I) cyanide plating baths Complexometric determination of nickel and indium

A method is described for rapid determination of nickel and indium in gold(I) cyanide baths containing large amounts of citric acid and/or sodium citrate, without previous destruction of organic matter. Gold is removed by extraction with ethyl acetate. In one aliquot of the solution indium is masked with thioglycollic acid and nickel is precipitated with sodium diethyldithiocarbamate, extracted into chloroform, stripped into water and determined complexometrically. In a second aliquot indium and nickel are precipitated together with the same reagent and stripped into water, then nickel is masked with 1,10-phenanthroline, and indium is determined by direct titration with EDTA.     

Application of direct thermometric analysis in iodometry

Elementary chlorine was determined by a thermometric method using potassium iodide as reagent. The temperature rise corresponding to the heat of reaction was proportional to the chlorine content. Iodine formed in the reaction was also determined with sodium thiosulphate. The heat of the chlorine-iodide reaction is about five times that of the iodine-thiosulphate reaction. Direct determination with potassium iodide is simpler and more rapid than the indirect one.     

Chelatometric determination of calcium and magnesium in iron ores, slags, anorthosite, limestone, copper-nickel-lead-zinc ores and divers materials

Chelatometric methods for the determination of calcium and magnesium in iron ores, slags, anorthosite, copper-nickel-lead-zinc ores and various other materials are described. Potential interfering elements are masked with triethanolamine and potassium cyanide. In one aliquot calcium is titrated at pH > 12, with calcein and thymolphthalein mixed indicator and in another aliquot calcium and magnesium are titrated in ammonia buffer, with o-cresolphthalein complexone screened with Naphthol Green B as indicator. The results compare favourably with certified values for reference materials of diverse nature.     

聚氧化乙烯絮凝-电感耦合等离子体发射光谱法测定土壤中水溶性钾、钠、钙、镁、硫酸根

建立了聚氧化乙烯絮凝-4000r/min离心,电感耦合等离子体发射光谱法（ICP-AES）测定土壤水溶性钠钾钙镁硫酸根离子的方法。本法在常规方法浸提的基础上,加入聚氧化乙烯絮凝剂使溶液中的胶体形成絮凝物聚沉,制得澄清溶液,消除了胶体对钾、钠、钙、镁吸附的干扰;采用电感耦合等离子体发射光谱法一次性测定钾、钠、钙、镁、硫酸根,相较传统方法简便快速,结果准确可靠。本法各离子检出限为0.37-2.91g/g,相对标准偏差小于5.55%,完全满足检测要求。该法操作简便,快速,实用性强,对环境无二次污染,已成功应用于土壤水溶性钾、钠、钙、镁、硫酸根离子的测试分析中,适合土壤批量样品分析。     

Determination of Atenolol and Its Related Compounds by Ion Pair High Performance Liquid Chromatography

Abstract

A rapid, simple, accurate, and stability-indicating ion pair high performance liquid chromatography (IP HPLC) procedure is presented for the determination of atenolol in pharmaceutical tablets. The related compounds of atenolol were separated, making the determination specific for atenolol. An aliquot of the sample is dissolved in methanol containing N-butyryl-4-aminophenol as an internal standard and chromatographed on a supelcosil LC-8-DB (5μ) (25Omm × 4.6mm i.d.) column using 1.0 mM ammonium acetate and 2.0 mM octanesulfonic acid sodium salt in acetonitrile: water (25:75) solution adjusted to pH 3.5 with glacial acetic acid as the mobile phase. The detection was carried at 225 nm. The relative standard deviations are less than 1.0% for the two commercial products analyzed. The method was tested for linearity, recovery, and specificity.     

聚氧化乙烯絮凝-电感耦合等离子体原子发射光谱(ICP-AES)法测定土壤中水溶性钾、钠、钙、镁、硫酸根

建立了聚氧化乙烯絮凝-4000 r/min离心,电感耦合等离子体原子发射光谱(ICP-AES)法测定土壤水溶性钠、钾、钙、镁、硫酸根离子的方法.在常规方法浸提的基础上,加入聚氧化乙烯絮凝剂使溶液中的胶体形成絮凝物聚沉,制得澄清溶液,消除了胶体对钾、钠、钙、镁吸附的干扰;采用电感耦合等离子体原子发射光谱法测定钾、钠、钙、...     

Rapid analysis of fertilizers by the direct-reading thermometric method

The authors have developed rapid methods for the determination of the main components of fertilizers, namely phosphate, potassium and nitrogen fixed in various forms. In the absence of magnesium ions phosphate is precipitated with magnesia mixture; in the presence of magnesium ions ammonium phosphomolybdate is precipitated and the excess of molybdate is reacted with hydrogen peroxide. Potassium is determined by precipitation with silico-fluoride. For nitrogen fixed as ammonium salts the ammonium ions are condensed in a basic solution with formalin to hexamethylenetetramine; for nitrogen fixed as carbamide the latter is decomposed with sodium nitrite; for nitrogen fixed as nitrate the latter is reduced with titanium(III). In each case the temperature change of the test solution is measured. Practically all essential components of fertilizers may be determined by direct-reading thermometry; with this method and special apparatus the time of analysis is reduced to at most about 15 min for any determination.     

Determination of Artificial Sweeteners by High-Performance Ion-Mobility Spectrometry with Electrospray Ionization

There are increasing demands for simple, rapid, low-cost, and green methods for the determination of artificial sweeteners that are of concern because of their toxicity. Acesulfame-K, sodium saccharin, sodium cyclamate, aspartame, and neotame were determined by high-performance ion-mobility spectrometry with direct electrospray ionization (ESI-HPIMS). The resolving power exceeded 60 in both positive- and negative-ion modes. The single acquisition time was less than 10?s and the total analysis time was under 2?min which is faster than traditional chromatography methods. Calibration curves were established for the sweeteners at concentrations from 0.1 to 1.5 or 2.0?mg/L with correlation coefficients of approximately 0.99. The combination of simple sample preparation, fast analysis, high sensitivity, robustness, green properties, and low cost makes ESI-HPIMS a promising technique for the determination of acesulfame-K, sodium saccharin, sodium cyclamate, aspartame, and neotame in water and beverages.     

Precise coulometric titration of sodium thiosulfate and development of potassium iodate as a redox standard

In this paper, we determine the effective purity of potassium iodate as a redox standard with a certified value linked to the international system of units (SI units). Concentration measurement of sodium thiosulfate solution was performed by precise coulometric titration with electrogenerated iodine, and an assay of potassium iodate was carried out by gravimetric titration based on the reductometric factor of sodium thiosulfate assigned by coulometry. The accuracy of the coulometric titration method was evaluated by examining the current efficiency of iodine electrogeneration, stability of sodium thiosulfate solutions and dependence on the amount of sodium thiosulfate solution used. The measurement procedure for gravimetric titration of potassium iodate with sodium thiosulfate was validated based on determination of a reference material of known purity (potassium dichromate determined by coulometry with electrogenerated ferrous ions) using the same gravimetric method. Solutions of 0.2 and 0.5 mol/L sodium thiosulfate were stable over 17 days without stabilizer. Investigation of the dependency of titration results on the amount of sodium thiosulfate solution used showed no significant effects, no evidence of diffusion of the sample, and no effect of contamination appearing during the experiment. Precise coulometric titration of sodium thiosulfate achieved a relative standard deviation of less than 0.005% under repeating conditions (six measurements). For gravimetric titration, the results obtained for the effective purity of potassium dichromate were sufficiently close to its certified value to allow confirmation of the validity of the gravimetric titration was confirmed. The relative standard deviation of gravimetric titration for potassium iodate was less than 0.011% (nine measurements), and a redox standard with a certified value linked to SI units was developed.     

Potentiometric determination of free acidity in presence of hydrolysable ions and a sequential determination of hydrazine

A simple potentiometric method for the determination of free acidity in presence of hydrolysable ions and sequential determination of hydrazine is developed and described. Both free acid and hydrazine are estimated from the same aliquot. In this method, free acid is titrated with standard sodium carbonate solution after the metal ions in solutions are masked with EDTA. Once the end point for the free acid is determined at pH 3.0, an aliquot of formaldehyde is added to liberate the acid equivalent to hydrazine which is then titrated with the same standard sodium carbonate solution using an automatic titration system. The described method is simple, accurate and reproducible. This method is especially applicable to all ranges of nitric acid and heavy metal ion concentration relevant to Purex process used for nuclear fuel reprocessing. The overall recovery of nitric acid is 98.9% with 1.2% relative standard deviation. Hydrazine content has also been determined in the same aliquot with a recovery of nitric acid is 99% with 2% relative standard deviation. The major advantage of the method is that generation of corrosive analytical wastes containing oxalate or sulphate is avoided. Valuable metals like uranium and plutonium can easily be recovered from analytical waste before final disposal.     

Rapid laser fluorometric method for the determination of uranium in soil, ultrabasic rock, plant ash, coal fly ash and red mud samples

A simple and rapid laser fluorometric determination of trace and ultra trace level of uranium in a wide variety of low uranium content materials like soil, basic and ultra basic rocks, plant ash, coal fly ash and red mud samples is described. Interference studies of some common major, minor and trace elements likely to be present in different, geological materials on uranium fluorescence are studied using different fluorescence enhancing reagents like sodium pyrophosphate, orthophosphoric acid, penta sodium tri-polyphosphate and sodium hexametaphosphate. The accurate determination of very low uranium content samples which are rich in iron, manganese and calcium, is possible only after the selective separation of uranium. Conditions suitable for the quantitative single step extraction of 25 ng to 20 μg uranium with tri-n-octylphosphine oxide and single step quantitative stripping with dilute neutral sodium pyrophosphate, which also acts as fluorescence enhancing reagent is studied. The aqueous strip is used for the direct laser fluorometric measurement without any further pretreatment. The procedure is applied for the determination of uranium in soil, basalt, plant ash, coal fly ash and red mud samples. The accuracy of the proposed method is checked by analyzing certain standard reference materials as well as synthetic sample with known quantity of uranium. The accuracy and reproducibility of the method are fairly good with RSD ranging from 3 to 5% depend upon the concentration of uranium.     

Determination of abamectin and azadirachtin residues in orange samples by liquid chromatography-electrospray tandem mass spectrometry

A rapid and sensitive LC-ESI-MS-MS method has been developed for the determination of azadirachtin and abamectin residues in orange samples. Samples were extracted with acetonitrile, in a high-speed blender. After the addition of sodium acetate, an aliquot of extract was directly injected into the LC-ESI-MS-MS system. The highest sensitivity of the method was achieved under MS-MS conditions using [M+Na]+ adducts as precursor ions. Recoveries for both compoundsfrom spiked orange samples at 0.01 and 0.1 mg/kg were above 80%, with good repeatability (<10%). Method detection limits achieved (<0.007 mg/kg) were adequate for the determination of these pesticides in this kind of sample from the regulatory point of view. The importance of the solvent used for extraction, as well as the addition of sodium acetate to the extracts and the selection of adequate chromatographic conditions are discussed.     

电感耦合等离子体原子发射光谱法同时测定高强度玻璃纤维粉体中9种金属元素

建立电感耦合等离子体原子发射光谱法测定高强度玻璃纤维粉体中铝、镁、钙、铁、钛、锂、铈、钠、钾9种金属元素含量的方法。采用氢氟酸、高氯酸和盐酸分两段溶解样品,分别在选定的各元素分析谱线下,采用电感耦合等离子体原子发射光谱仪测定各元素含量。9种金属元素在各自的质量浓度范围内与光谱强度成良好的线性关系,相关系数均大于0.999,检出限为8.0~17.4 μg/g。测定结果的相对标准偏差小于1.8%(n=6),加标回收率为97.6%~103.7%。该方法准确,简便,快速,适用于高强度玻璃纤维中多金属元素的同时测定。     

Determination of free acidity in antimony chloride solutions

A method for the determination of free acid in antimony(III) chloride solutions is described. The total acid is determined by titration in the presence of tartrate as masking agent, and the bound acidity is calculated from the antimony content of the same aliquot, determined by titration with bromate. This method is simple and rapid compared to the earlier potentiometric techniques.     

Improvements in the sample preparation for the determination of ruthenium in catalysts by different spectrometric techniques

The sample preparation steps of two analytical methods for the determination of ruthenium in carbon supported catalysts with flame atomic absorption spectrometry (FAAS) or UV-vis spectrophotometry, were carefully optimised. As a first step, the carbon support is ignited in air at 450 degrees C then the residue is fused with potassium hydroxide and potassium nitrate to convert ruthenium into ruthenate anion RuO4(2-). The melt is dissolved in water with potassium persulphate and potassium hydroxide as stabilisers. Ruthenium may be directly estimated by measuring the UV-vis molecular absorption of ruthenate at the isosbestic point of the ruthenate-perruthenate mixture or by FAAS. In the latter case, an aliquot of the sample solution is added to the concentrated hydrochloric acid to obtain hexachlororuthenate RuCl6(2-), that is nebulized into the flame after proper dilution. This novel procedure allows to determination of ruthenium without the sensitivity loss (-66%) which occurs in the alkaline media resulting from the fusion. The relative standard deviation is 1.1% for FAAS and 1.3% for UV-vis, at 5% Ru (n = 7). The detection limit (3sB) is 0.07% Ru for FAAS and 0.02% Ru for UV-vis. Both methods were applied to the analysis of a commercial sample and a statistical comparison was carried out.     

The rapid determination of silica in rocks and minerals

A method is described for the rapid determination of silica in various substances by precipitation of potassium fluorosilicate ; calcium ions are used. to repress coprecipitation of aluminium and titanium. Solubility is reduced by low pH and excess potassium chloride. The separated precipitate is titrated with standard sodium hydroxide solution using phenolphthalein as indicator.     

Determination of major and minor elements in silicates by inductively coupled plasma emission spectrometry

A simple rapid method for the determination of major and minor elements in silicates is reported. Powdered sample (50 mg) is treated with hydrochloric and hydrofluoric acids in a small sealed Teflon vessel. After addition of boric acid, silicon, aluminium, iron, titanium, manganese, calcium, magnesium, sodium, and potassium are determined by inductively coupled plasma emission spectrometry. The method is satisfactory for a variety of standard silicate materials.     

气相色谱-负化学离子源质谱测定大豆和玉米中12种三唑类杀菌剂的残留量

建立了一种可用于大豆和玉米中12种三唑类杀菌剂残留量测定的分散固相萃取-气相色谱-负化学离子源质谱方法。样品经含1%冰醋酸的乙腈提取,分散固相萃取法净化,采用气相色谱-负化学离子源质谱分时段选择离子监测技术进行测定与确证,外标法定量。12种农药在50～1000 μg/L范围内线性关系均良好;所有农药的方法定量限(LOQ)均低于8 μg/kg;在10,20和40 μg/kg 3个添加水平下所有农药的回收率为70%～130%,相对标准偏差(RSD)≤13.9%。该方法在检测大豆和玉米基质时无干扰现象出现。     

Spectrophotometric determination of pentaerythritol tetranitrate (PETN) in waste water from lead styphnate primer plants

An accurate spectrophotometric method is proposed for the determination of pentaerythritol tetranitrate (PETN) in waste water from lead styphnate primer plants by use of phenoldisulphonic acid. The waste water is filtered through a sintered glass crucible and the PETN is determined in the filtrate and the residue. In the determination of PETN in the filtrate, sodium hydroxide is added and the PETN is extracted with methylene chloride (in alkaline solution, styphnate and TNT are not extracted). The methylene chloride solution is then evaporated to dryness, the residue is treated with a solution of phenoldisulphonic acid in sulphuric acid, water and ammonia are added, and the yellow colour is measured. In the determination of PETN in the residue, the PETN is dissolved in acetone, an aliquot of the acetone solution is treated with water and sodium hydroxide, the PETN is extracted with methylene chloride and the colour is developed as above. Various factors affecting the determination were investigated. The solubility of PETN in water was studied.     

氢氧化钡沉淀–碘量法对高锰酸钾和锰酸钾共存时的分别测定

采用氢氧化钡沉淀–碘量法对高锰酸钾和锰酸钾共存时的含量分别进行测定。向电解液中加入过量的饱和氢氧化钡溶液,利用锰酸钡和高锰酸钡溶度积的不同进行分离,再用碘量法分别对高锰酸钾和锰酸钾进行测定。结果表明,高锰酸钾和锰酸钾的检出限分别为0.061,0.077 g/L,测定结果的相对标准偏差分别为0.57%和0.72%(n=4),高锰酸钾的加标回收率为94.12%~95.85%。t检验结果表明,氢氧化钡沉淀–碘量法与传统方法对高锰酸钾和锰酸钾的测定结果无显著性差异。该法避免了亚铅酸钠和铬盐的毒性及滴定终点颜色不易判断等缺点,适合于高锰酸钾工业生产中主要成分的快速检测。