The determination of periodate by infrared spectroscopy

An infrared method has been developed to determine periodate on the microgram scale. Periodate is precipitated in slightly acid solution with tetraphenylarsonium chloride and in presence of perchlorate as carrier. The precipitate is mixed with powdered potassium bromide and pressed into a disc. The base-line absorbance of the periodate band at 11.68 μ is calculated in order to find the concentration of periodate from a calibration curve. No interference is caused by perchlorate, permanganate, perrhenate, chlorate, iodate or bromate.     

Consecutive indirect titration of periodate and iodate with EDTA

Periodate and iodate (μmol amounts) are determined successively in the same solution by their selective oxidation of iron(II) at pH 2.0 and in acetic acid, respectively. The resultant iron(III) is titrated with EDTA solution to a sulphosalicylic acid end-point. Bromate—iodate mixture can be titrated similarly.     

Bromine number determination by coulometric flow-injection titration

The bromine number, the number of grams of bromine which react with 100 grams of a substance under given conditions, is a widely used parameter in the chemical and petroleum industries. A method of performing the bromine number determination by coulometric flow-injection titration, using both sequential injection with sinusoidal flow and single zone techniques, is described. Titrations of olefins, known interfering compounds, and petroleum distillates were performed and compared with the results of conventional bromine number titrations. Analyses yielded a relative standard deviation of 2%. Results compared favorably with those obtained by the conventional method for both pure (97%) olefins and petroleum distillates. The method was found to be insensitive to interference from nitrogen compounds. The CFIT technique combines the advantages of coulometric titrations: controlled generation of reagent, avoidance of reagent standardization requirements and reagent storage and stability problems; with the advantages of FIA: small volume requirements which reduce cost and waste, controllable dilution through flow programming, toxic materials contained within a closed environment, and the capability of being automated.     

Binding isotherm determination by isothermal titration calorimetry

Journal of Thermal Analysis and Calorimetry - A simple method for determination of binding isotherm in the protein-ligand interaction was introduced using isothermal titration calorimetric data....     

Spectrophotometric determination of periodate and iodate by a differential kinetic method

A rapid, simple and sensitive differential kinetic method is presented for the determinations of periodate and iodate ions. The method is based on their reaction with iodide in the presence of methylene blue. The reactions can be monitored spectrophotometrically by measuring the decrease in absorbance at 665 nm. Two sets of conditions were established that in one set of conditions only periodate reacted with iodide but in the other set both the ions reacted with iodide during the first 180 s after initiation of the reaction. The data were evaluated by proportional equations. The method allowed the determination of periodate and iodate at concentrations between 0.1 and 1.0 and 0.1 and 1.3 mug ml(-1), respectively. The method was applied to the determination of periodate and iodate in tap water and spring water with satisfactory results.     

Amplification method for the titrimetric determination of L-rhamnose by periodate oxidation

The stoichiometry of the oxidation of rhamnose by periodate has been studied using a method based on the determination of iodate. Conditions have been found under which one mole of rhamnose stoichiometrically reduces six moles of periodate. An amplification method for the titrimetric determination of rhamnose is proposed in which one mole of rhamnose reacts with 6 moles of periodate with the formation of six moles of iodate, which is equivalent to 18 moles of triiodide, in the titration of which 36 gram-equivalents of sodium thiosulfate are consumed. The method is distinguished by high sensitivity and accuracy. The relative standard deviation in the determination of 2–3.5 mg of rhamnose does not exceed 0.5–1%.Biokhimreaktiv Scientific Production Association. All-Union Scientific-Research Institute of Applied Biochemistry, Olaine. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 21–24, January–February, 1984.     

自动电位滴定法快速测定钾盐中的钾含量

钾含量的测量常用火焰光度法和四苯硼钾重量法。火焰光度法适用于微量分析 ,对较高含量钾的测定误差较大 ,四苯硼钾重量法的测定准确度高 ,但操作繁琐 ,测定周期长 ,易出错。本文采用四苯硼钠溶液电位滴定法 ,测定高、中含量组分钾 ,测定周期短 ,所用试剂少 ,且不受样品中水不溶物的干扰 ,选择性好 ,测定的准确度和精密度均在 0 .2 %以下 ,适用于钾盐、卤水、复合肥和钾肥中钾的测定。1　实验部分1 .1　仪器和药品ZD 2型自动电位滴定仪 (上海雷磁仪器厂 ) ,PK 1型钾离子选择电极 ,2 1 7型饱和甘汞电极 (双盐桥 )。四苯硼钠标准液 :0 .1mol…     

丽春红G-高碘酸钾催化光度法测定痕量锇

以Os(Ⅳ )催化高碘酸钾氧化丽春红G(PG)的褪色反应为基础 ,在 90℃加热 1 2min和 5 0 0nm波长处采用固定时间法测定丽春红G吸收值的降低 ,建立了测定痕量锇 (Ⅳ )的新方法。锇 (Ⅳ )的质量浓度在 0～ 0 48μg/L范围内呈良好的线性关系 ,检出限为 6 2× 1 0 - 9mg/L。对 0 4μg/L锇 (Ⅳ )测定的相对标准偏差为 0 71 % (n =1 1 )。催化反应对Os(Ⅳ )和丽春红G均为一级反应 ,催化反应的表观活化能为 78 80kJ/mol。所提出的方法在蒸馏分离后已应用于某些岩矿及冶金产品中锇的测定     

Triphenyltetrazolium chloride for determination of iodate and periodate

Optimum conditions for complexation in the systems triphenyl-tetrazolium chloride-iodate-iodide-dichlorethane and triphenyltetrazolium chloride-periodate-iodide-dichlorethane were found. The molar absorptivity of the complex was 7.48 x 10(4) 1. mole(-1). cm(-1) for the iodate, and 9.09 x 10(4)1. mole(-1) cm(-1) for the periodate. Beer's law is adhered to in the range of 0.04-0.7 mug/ml for iodate and 0.02-0.35 mug/ml for periodate. The influence of foreign ions was studied. Cr(VI), Hg(II) and S(2)O(2-)(3) interfere. The proposed method has been applied to analysis of iodate and periodate in fresh water.     

The determination of fluoride by titration with calcium chloride

A new method for the determination of fluoride ions is described. Precipitation is effected with an excess of standard calcium chloride and, after standing overnight, the unconsumed calcium ions are back-titrated with ethylenediamine tetra-acetic acid (EDTA) using Eriochrome Black T as indicator. Halides, sulphate, phosphate and arsenate do not interfere under the recommended conditions. The method is applicable over the range 5-65 mg of fluoride ion.     

Direct determination of thiol pKa by isothermal titration microcalorimetry

Knowledge of the acid dissociation constant (pKa) of a molecule is a critical step toward understanding its structure and reactivity. Current methods for pKa measurement, including electrochemical, spectroscopic, and spectrophotometric titrations, have proven to be useful but also have significant limitations. To overcome these limitations, we report the use of isothermal titration calorimetry (ITC) as a new method for pKa determination. We demonstrate by the measurement of the pKa values for free cysteine, glutathione, and a cysteine residue in a protein that this method is rapid and accurate.     

Analysis of α-glycolic compounds using the potentiometric differentiated titration of periodate and formaldehyde

The conditions of the analysis of -glycolic compoounds (ethylene glycol, glycerol, mannitol, D-glucose, D-ribose, and dihydroxyacetone) using the potentiometric differentiated titration of periodate and formaldehyde have been studied. A procedure for quantitative determination is proposed and the possibilities have been shown of using it for evaluating the stoichiometry of oxidation and the separate analysis of two-component mixtures. The performance of the determinations is distinguished by simplicity and adequate reliability.All-Union Scientific-Research Institute of Applied Biochemistry. Biokhimreaktiv Scientific-Production Association, Olaine. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 305–309. May–June, 1985.     

Spectrofluorimetric flow injection determination of trace amounts of periodate

A sensitive, rapid and selective procedure is proposed for the flow injection determinations of periodate by spectrofluorometric detection. The method is based on the reaction of periodate with Alizarin Navy Blue in basic solution. The reagents and manifold variables influence on the sensitivity have been investigated and the optimum conditions are established. Periodate can be determined for the range of 0.250-5.00 microg ml(-1) with a limit of detection of 0.08 microg ml(-1), and with a sample rate of 15 +/- 2 samples h(-1). The relative standard deviations for eight replicate determination of 0.500 and 5.00 microg ml(-1) was 1.3 and 1.1%, respectively. Periodate can be determined in the presence of iodate and bromate. The proposed method was used to determination of periodate in water samples.     

Indirect determination of fluorides by the EDTA titration of samarium

Fluorides are determined by the back-titration of excess of samarium with EDTA to the canary yellow end-point of Methylthymol Blue. The fluoride is precipitated and digested in a solution buffered at pH 2.5-3.0 with monochloroacetate buffer. After digestion, the pH is adjusted to 5.6-5.8 with pyridine and the excess of samarium is back-titrated in the presence of the precipitate, for samples with small quantities of fluoride. The procedure was used to analyse simple fluorides, fluoroborates and some other fluoro-complexes.     

The determination of copper by complexometric titration with ethylenediaminetetraacetic acid

A method has been developed for the determination of cupric copper by complexometric titration with ethylen.ediaminetctraacetic acid. The titrations were followed potentiometrically, and were effected at pH 5–6 in the presence of an ammonium acetate buffer. Interfering metals such as ferric iron, aluminium, cadmium, zinc, manganese, nickel, cobalt and lead must be removed by a preliminary separation.     

酸碱滴定法间接测定重晶石中的硫酸钡

利用偏磷酸与重晶石在400℃时的复分解反应，将硫酸钡转化为聚偏磷酸钡，同时生成的H2SO4在高温下可挥发除去。在强碱性溶液和过氧化氢的作用下，聚偏磷酸钡转化为有确定磷钡比的磷酸钡。将磷酸钡用盐酸溶解后，在CaCl2存在下，以甲基红和酚酞为指示剂，用氢氧化钠标准溶液滴定磷酸，以间接测定重晶石中硫酸钡的含量。本法所需时间6h，分析结果与标准方法（SN／T0480．5－95）吻合，RSD为0．33％－0．68％。     

Spectrophotometric determination of epinephrine and norepinephrine with sodium periodate

A simple and accurate spectrophotometric method is described for the determination of epinephrine (EP), norepinephrine (NE) and their bitartrate salts. The method is based on the development of a red colour (lambda(max) 490 nm) with sodium periodate in aqueous alcoholic medium. The colour is stable for at least 1 hr. The molar reacting ratio of EP or NE to periodate is 1:2. The proposed method is particularly suitable for routine analysis of EP and NE injections. The interference due to the sodium metabisulphite normally used as antioxidant can be overcome by addition of acetone. Results for analysis of bulk drugs and injections agree well with those of official methods.