Permanganate Methods

There are also numerous titrimetric methods for determining macro amounts of selenium including the iodometric, thiosulfate, and permanganate methods. In one of the several iodometric methods, the dissolved selenium is reduced from Se(IV), if an excess of potassium iodide is added ... 

The excess Na2S202 is back-titrated with standard iodine solution. The permanganate method is based on the oxidation of Se(IV) to Se(VI). 

Potassium Dichrom te. This method is similar ia appHcation to the potassium permanganate method. 

The iodometric method has the advantage over the permanganate method (Section 10.95) that it is less affected by stabilisers which are sometimes added to commercial hydrogen peroxide solutions. These preservatives are often boric acid, salicylic acid, and glycerol, and render the results obtained by the permanganate procedure less accurate. 

The periodate-permanganate method used was based on a method described previously [105], but three changes from the original published procedure were found to be necessary. A sample size of 50 mg was taken for all oxidations. The same quantities of oxidant, potassium carbonate, and sodium bisulfite (26 ml, 45 mg, 1.06 g, respectively) were used for all samples. An inert marker (5 mg) of methyl palmite or stearate was added to all samples prior to oxidation to serve as a rough check on the completeness of oxidation and the recovery of fragments. 

The permanganate methods essentially consist of three ways to assay pharmaceutical substances ... 

Potassium Permanganate Method for Organic Impurities. Place in one of tbe two identical test tubes lOmI of the sample, while in the other tubes are placed 10ml of the standard soln of par 4.3 6. Adjust the temp in each tube to 25t0.2° and add to each tube one drop of. soln contg Ig K permanganate per liter of... 

Permanganate ion forms ion-pairs with the tetraphenylarsonium [17,18]-, ethylenebis(triphenylphosphonium) [19,20], trimethylenebis(triphenylphosphonium) [21,22], and benzyltributylammonium [23,24]- cations, soluble in chloroform and in other solvents. These compounds are used in the extractive variants of the permanganate method. 

The solubility of CaSe04-2H20(cr) in water was determined between 270.6 and 375.4 K. The calcium concentration was found by the oxalate-permanganate method and by a complexometric titration. As the solubility data are not readily available they are reproduced in Table A-16. 

Alkalinity, Chemical Oxygen Demand by potassium permanganate method (CODMn), Dissolved Oxygen (DO), Total and Calcium Hardness, Salinity, Sulfides, Cu, Cr and Fe were the monitored quality parameters, using standard titrimetric analytical methods according to Romanian regulations and UV-VIS spectrometry by standard addition method (Chirila et al., 2005). 

FIGURE 5. The distribution of dissolved oxygen (DO), chemical oxygen demand by potassium permanganate method (CODMn) and sulfides in Tabacarie lake s pollution sources in July 2005 (mean values). 

Neubauer-Loewenthal = permanganate method Direct or indirect (after precipitation of tannins) oxidative titration using permanganate. poor reproducibility 58,105,106... 

Varies with method used. Oonven lent with permanganate method when available. Otherwise r e qnfrea rather balky apparatus. Requires exposures of d to IS hours. 

Classical methods for analysis of manganese have been the periodate method in air, and the permanganate method in water (Saric 1986). Nowadays, among the solid-state analytical methods available, neutron activation analysis (NAA) is the most reliable to determine manganese in biological and environmental materials. This method of choice combines both high specificity, sensitivity and reproducibility for very low concentrations of manganese, whereas X-ray fluorescence (XRF) spectroscopy showed standardization problems and arc/ spark emission spectroscopy suffered from electrode contamination (Chiswell and Johnson 1994). 

In the determination of chromium (Table VI), none of the methods studied gave very good results. The accuracy of the permanganate (6) and alkaline hypobromite (7) procedures were only fair, and the precision of the permanganate method was rather poor. 

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