Determination of perchlorate in samples of potassium chlorate. II

Summary A method of determining perohlorate is described which involves extraction as tetrabutylphosphonium perchlorate intoo-dichlorobenzene and the subsequent indirect determination by measurement of the absorbance of the iron(III)-thiocyanate-tetrabutylphosphonium complex formed by washing the extract with an aqueous solution containing iron(III) and thiocyanate. The method has been successfully applied to the determination of as little as 0.003 per centw/w of perchlorate in samples of potassium chlorate.

---

Zusammenfassung Eine Methode der Perchloratbestimmung wurde beschrieben. Tetrabutylphosphoniumperchlorat wird mit o-Dichlorbenzol extrahiert. Der Extrakt wird mit einer wäßrigen, Eisen(III) und Rhodanid enthaltenden Lösung gewaschen, und dann die Absorption des Eisen(III)-Rhodanid-Tetrabutylphosphonium-Komplexes gemessen. Die Methode wurde mit Erfolg zur Bestimmung von nur 0,003% (g/g) Perchlorat in Kaliumchlorat angewandt.

---

---

Part I: Mikrochimica Acta1970, 888.     

Determination of perchlorate in samples of potassium chlorate. I

Summary A method has been developed for the determination of small amounts of potassium perchlorate in admixture with potassium chlorate. The method involves preliminary decomposition of the potassium chlorate by boiling with concentrated hydrochloric acid, preparing a disc from the dried residue, and measuring its absorbance at 628 cm^–1.

---

Zusammenfassung Eine Methode zur Bestimmung kleiner Mengen Kaliumperchlorat in Gegenwart von Kaliumchlorat wurde ausgearbeitet. Sie beruht auf der vorhergehenden Zersetzung des Chlorats durch Kochen mit konz. Salzsäure, Herstellung einer Scheibe aus dem Trockenrückstand und Messung ihrer Absorption bei 628 cm^–1.

     

Ion chromatographic determination of chloride,chlorate, and perchlorate in sulfuric acid solutions

Summary The determination of chloride and perchlorate by non-suppressed ion chromatography in aqueous process solutions containing a high sulfate background is described. The method is reliable and fast. The sensitivity for perchlorate is lower than for other anions like nitrate, nitrite and chlorate. The detection limits are about 0.3 g/ml with linear calibration curves within a concentration range from 1 to 50 g/ml.     

Rapid estimation of chlorate in presence of perchlorate

Summary A rapid and simple method is described for the determination of chlorate in the presence of a large amount of perchlorate. The solution containing the mixture is acidified with either sulphuric acid or hydrochloric acid and titrated in the presence of sodium bromide directly against titanous chloride using quinoline yellow as indicator near the end point. The limit of uncertainty of the method is 0.361 mg for a sample analysing 52.48 mg of sodium chlorate.     

高效液相色谱-串联质谱法测定奶粉中氯酸盐和高氯酸盐

建立了一种测定奶粉中氯酸盐和高氯酸盐含量的高效液相色谱-串联质谱方法。样品经0.1%（v/v）甲酸水-乙腈提取,10000 r/min下离心10 min后,上清液经PRiME HLB固相萃取柱净化;采用离子交换色谱分离,色谱柱为Thermo Scientific Acclaim TRINITY P1复合离子交换柱（50 mm×2.1 mm,3 μm）,以乙腈和20 mmol/L乙酸铵溶液为流动相进行梯度洗脱,MS/MS检测,内标法定量。结果显示,氯酸盐和高氯酸盐分别在2.0~40.0 μg/L和1.0~20.0 μg/L范围内线性关系良好,相关系数（r²）大于0.999,方法的定量限分别为15.0和7.5 μg/kg。氯酸盐和高氯酸盐分别在30.0、60.0、120.0 μg/kg和15.0、30.0、60.0 μg/kg 3个水平下的加标回收率为89.24%~107.85%,相对标准偏差为3.15%~10.42%（n=6）。该方法简便快捷、准确可靠,能适用于奶粉样品的测定。     

Determination of traces of free acid in uranyl salt solutions

A method for the determination of free acid in the presence of uranium(VI) is suggested. It involves the extraction of uranium by TBP from a solution saturated with potassium nitrate or chioride in order to prevent interference from the hydrolysis of uranium. The end-point is detected potentiometrically at pH 3.4. The method is suitable for the determination of 0.1–1.5 millimoles of acid in the presence of as much as 1.0 millimole of uranium.     

Determination of chloride, chlorate and perchlorate by PDMS microchip electrophoresis with indirect amperometric detection

In this work, chloride, chlorate and perchlorate are fast separated on PDMS microchip and detected via in-channel indirect amperometric detection mode. With PDMS/PDMS microchip treated by oxygen plasma, anions chloride (Cl-), chlorate (ClO3-), and perchlorate (ClO4-) are separated within 35s. Some parameters including buffer salt concentration, buffer pH, separation voltage and detection potential are investigated in detail. The separation conditions using 15 mM (pH 6.12) of 2-(N-morpholino)ethanesulfonic acid (MES)+L-histidine (L-His) as running buffer, -2000 V as separation voltage and 0.7 V as detection potential are optimized. Under this condition, the detection limits of Cl-, ClO3-, and ClO4- are 1.9, 3.6, and 2.8 microM, respectively.     

Determination of traces of boron and cadmium in manganese sulphate solutions

Summary A well established method to calibrate ²⁵²Cf neutron sources makes use of a manganese bath technique based on the measurement of the induced ⁵⁶Mn-,-radioactivity. The knowledge of the impurities present in the bath is required because they may affect the results of the source strength measurements by their neutron absorption properties. Some specific impurities which may introduce a significant correction must be quantified and selective methods have to be used for their determination. The determination of two of these specific impurities, having a high capture cross section for neutrons, the boron and the cadmium, is described; it is based on spectrophotometry with curcumin (for B) and on pulse polarography (for Cd). Analytical results obtained on baths prepared in different laboratories are given. Errors are ±4–7% for B and ±3% for Cd.

---

Bestimmung von Bor- und Cadmiumspuren in Mangansulfatlösungen

Zusammenfassung Eine übliche Methode zur Eichung von ²⁵²Cf-Neutronenquellen basiert auf der Manganbad-Technik, wobei die induzierte ⁵⁶Mn-,-Aktivität gemessen wird. Die Ergebnisse können durch Verunreinigungen des Bades beeinflußt werden. Methoden zu deren selektiver Erfassung sind daher notwendig. Die Bestimmung von Bor und Cadmium, die einen besonders hohen Einfangquerschnitt für Neutronen haben, wird beschrieben. Sie beruht auf der spektralphotometrischen Bestimmung mit Curcumin (für B) bzw. auf der pulspolarographischen Bestimmung (für Cd). Analysenwerte für verschiedene MnSO₄-Bäder werden verglichen. Die Fehler liegen im Bereich von ±4–7% (für B) und ±3% (für Cd).

     

Investigation of the anodic processes on platinum in perchlorate and chlorate solutions by linear sweep voltammetry using the rotating double-ring electrodes

The polarographic behavior of chloramine-T has been investigated over a wide pH range. Chloramine-T gives two waves at low concentration. In acidic solution, the second wave is due to the formation of mercurous chloride, whereas, in alkaline solution, the second wave is due to the formation of the mercuric salt of p-toluenesulfonamide. The diffusion current of the total wave is due to a two-electron reduction, is proportional to the concentration and is stable, particularly in alkaline solution. The polarographic behavior of the anodic wave of p-toluenesulfonamide has also been investigated.     

Determination of diffusion coefficients of Cu(I) ions in concentrated perchlorate solutions

The diffusion coefficients of Cu(I) ions in concentrated aqueous Ca(ClO₄)₂ solutions have been determined from the limiting currents of anodic oxidation at the rotating disc electrode.

---

Zur Bestimmung der Diffusionskoeffizienten von Cu(I)-Ionen in konzentrierten Perchloratlösungen (Kurze Mitteilung)

Zusammenfassung Diffusionskoeffizienten von Cu(I)-Ionen in konzentrierten wäßrigen Ca(ClO₄)₂-Lösungen wurden durch Messung der anodischen Grenzströme an der rotierenden Scheibenelektrode bestimmt.

     

Structure of aqueous sodium perchlorate solutions

Salt solutions have been the object of study of many scientists through history, but one of the most important findings came along when the Hofmeister series were discovered. Their importance arises from the fact that they influence the relative solubility of proteins, and solubility is directly related to one of today's holy grails: protein folding. In this work we characterize one of the more-destabilizing salts in the series, sodium perchlorate, by studying it as an aqueous solution at various concentrations ranging from 0.08 to 1.60 mol/L. Molecular dynamics simulations at room temperature permitted a detailed study of the organization of solvent and cosolvent, in terms of its radial distribution functions, along with the study of the structure of hydrogen bonds in the ions' solvation shells. We found that the distribution functions have some variations in their shape as concentration changes, but the position of their peaks is mostly unaffected. Regarding water, the most salient fact is the noticeable (although small) change in the second hydration shell and even beyond, especially for g(O(w)***O(w)), showing that the locality of salt effects should not be restricted to considerations of only the first solvation shell. The perturbation of the second shell also appears in the study of the HB network, where the difference between the number of HBs around a water molecule and around the Na(+) cation gets much smaller as one goes from the first to the second solvation shell, yet the difference is not negligible. Nevertheless, the effect of the ions past their first hydration shell is not enough to make a noticeable change in the global HB network. The Kirkwood-Buff theory of liquids was applied to our system, in order to calculate the activity derivative of the cosolvent. This coefficient, along with a previously calculated preferential binding, allowed us to establish that if a folded AP peptide is immersed in the studied solution, becoming the solute, then increasing the salt concentration will make the helix more stable.     

Spectrofluorimetric determination of traces of perchlorate by extraction with rhodamine 6G

A method for the spectrofluorimetric determination of perchlorate is described; it is based on extraction of the perchlorate-Rhodamine 6G ion-pair into benzene. The procedure is sensitive, highly reproducible and useful for the determination of 0.04-1.0 ppm of perchlorate. The determination of traces of perchlorate in chlorate is described.     

Determination of traces of sulfur in titanium

Summary The sample is dissolved in hydrochloric acid, and the evolved hydrogen sulfide and sulfur dioxide are absorbed in hydrogen peroxide and sodium hydroxide solutions. After complete dissolution, the sulfur in the absorbents and that remaining in the sample solution are converted with a hydriodic acid-formic acid-red phosphorus reducing mixture to hydrogen sulfide, which is absorbed in a zinc acetate solution and determined by the photometric methylene blue method. A few ppm of sulfur in titanium is determined with an error of ± 10% within 4 to 5 hours.

---

Zusammenfassung Die Probe wird in Salzsäure gelöst; Schwefelwasserstoff und Schwefeldioxid, die dabei entstehen, werden in Wasserstoffperoxid und Natronlauge absorbiert. Nach vollständiger Auflösung der Probe wird der Schwefel in den Absorptionslösungen und der in der Probelösung enthaltene Schwefel mit Hilfe eines reduzierenden Gemisches aus Jodwasserstoffsäure, Ameisensäure und rotem Phosphor zu Schwefelwasserstoff umgesetzt, der in Zinkacetat absorbiert und als Methylenblau photometrisch gemessen wird. Wenige ppm Schwefel in Titan können in 4 bis 5 Stunden auf ± 10% genau bestimmt werden.

     

Mechanoformation of ammonium perchlorate-potassium perchlorate solid solutions

Ammonium perchlorate-potassium perchlorate mixtures, upon pelletization, form a series of homogeneous solid solutions as manifested by X-ray powder diffractograms. Scanning electron microscopic studies throw light on the mechanism of the solid-solution formation. Solid solutions of ammonium perchlorate-potassium perchlorate have also been obtained by a modified cocrystallization technique. The thermal and combustion behavior of the solid solutions have also been studied, using the DTA technique and the Crawford strand burner.     

IR study of aqueous metal perchlorate solutions

Aqueous solutions of Mn(II), Co(II), Ni(II), and Zn(II) perchlorates, and for comparison, Mg(II) and Ca(II) perchlorates, have been studied by IR spectroscopy using HDO as an indicator. The investigations were carried out over the entire available concentration range of these salts. Computer deconvolution of the measured spectra demonstrates the effect of metal cations on the HDO molecules.