Hydrogen peroxide tests

Chromate, (i) Hydrogen peroxide test (IV.33, 4). (ii) Lead acetate solution test (IV.33,3). (iii) Action of hydrogen sulphide or sulphur dioxide (IV.33, 5,6). 

Chromate. Hydrogen peroxide test with amyl alcohol as organic solvent (IV.33, 4). 

Table 18.1 The average response and the coefficient of variation for a hydrogen peroxide test from a polymer-coated electrode lot. 

Titanic sulfate solution hydrogen peroxide tests.. . 128... 

Titanic Sulfate Solution Hydrogen Peroxide Tests... 

The colour sequence already described, for the reduction of van-adium(V) to vanadium(II) by zinc and acid, gives a very characteristic test for vanadium. Addition of a few drops of hydrogen peroxide to a vanadate V) gives a red colour (formation of a peroxo-complex) (cf. titanium, which gives an orange-yellow colour). 

Addition of hydrogen peroxide to a solution of a dichromate yields the blue colour of "peroxochromic acid. This is a test for soluble chromates and dichromates. 

The purple colour of this ion alone is a sufficient test for its presence addition of sulphuric acid and hydrogen peroxide discharges ihe colour. 

Dissolve about o i g. of />-phenylene diamine in about 10 ml. of water. Place 5 ml. of milk in each of two test-tubes A and B. Boil the milk in B thoroughly for 2 minutes and then cool. In each test-tube place 5 drops of the phenylenc diamine solution and then add i drop of 20 vol. hydrogen peroxide solution, and mix. A green coloration is produced in A, and then very rapidly changes to a slate-blue. No coloration is produced in B. This test therefore readily differentiates fresh from boiled milk. 

Detecting the presence of small, even invisible, amounts of blood is routine. Physical characteristics of dried stains give minimal information, however, as dried blood can take on many hues. Many of the chemical tests for the presence of blood rely on the catalytic peroxidase activity of heme (56,57). Minute quantities of blood catalyze oxidation reactions between colorless materials, eg, phenolphthalein, luco malachite green, luminol, etc, to colored or luminescent ones. The oxidant is typically hydrogen peroxide or sodium perborate (see Automated instrumentation,hematology). 

ImmunO lSS iy. Chemiluminescence compounds (eg, acridinium esters and sulfonamides, isoluminol), luciferases (eg, firefly, marine bacterial, Benilla and Varela luciferase), photoproteins (eg, aequorin, Benilld), and components of bioluminescence reactions have been tested as replacements for radioactive labels in both competitive and sandwich-type immunoassays. Acridinium ester labels are used extensively in routine clinical immunoassay analysis designed to detect a wide range of hormones, cancer markers, specific antibodies, specific proteins, and therapeutic dmgs. An acridinium ester label produces a flash of light when it reacts with an alkaline solution of hydrogen peroxide. The detection limit for the label is 0.5 amol. 

Nitrogen oxide sampling is simpler. This gas is drawn into an evacuated sample flask containing dilute sulfuric acid and hydrogen peroxide. The flask is shaken and allowed to stand for 16 h before the flask pressure is measured. Then the solution is made alkaline, and the nitrogen oxides are deterrnined by the phenoldisulfonic colorimetric test. 

The Reich test is used to estimate sulfur dioxide content of a gas by measuring the volume of gas required to decolorize a standard iodine solution (274). Equipment has been developed commercially for continuous monitoring of stack gas by measuring the near-ultraviolet absorption bands of sulfur dioxide (275—277). The deterrnination of sulfur dioxide in food is conducted by distilling the sulfur dioxide from the acidulated sample into a solution of hydrogen peroxide, foUowed by acidimetric titration of the sulfuric acid thus produced (278). Analytical methods for sulfur dioxide have been reviewed (279). 

In fastness to peroxide bleaching, ISO 10S-N02, the specimen is immersed ia a standard bleaching solution containing hydrogen peroxide (or sodium peroxide for viscose) where the composition of the bleaching Hquor is dependent on the fibers used ia the test specimen as are the pH and time of exposure (1—2 h). The objective of the test is to assess the colorfastness usiag typical bulk bleaching conditions for the fiber under test. 

Analytical Methods. Most of the analytical and testing methods used for ethyl ether are conventional laboratory methods. Ethyl ether that is to be used for anesthetic purposes or in processes that involve heating or distiHation must be peroxide-free, and should pass the USP standard test with potassium iodide. This test detects approximately 0.001% peroxide as hydrogen peroxide. 

PSS-SG composite film was tested for sorption of heme proteins hemoglobin (Hb) and myoglobin (Mb). The peroxidaze activity of adsorbed proteins were studied and evaluated by optical and voltammetric methods. Mb-PSS-SG film on PG electrode was shown to be perspective for detection of dissolved oxygen and hydrogen peroxide by voltammetry with linear calibration in the range 2-30 p.M, and detection limit -1.5 p.M. Obtained composite films can be modified by different types of biological active compounds which is important for the development of sensitive elements of biosensors. 

The addition rate of the hydrogen peroxide must be adjusted so that the temperature of the reaction mixture does not rise above 10 C. The yield is reduced if the temperature is allowed to rise above that point. The end point of the reaction, when excess peroxide is present, can be determined with potassium iodide - starch test paper. The yield also is reduced if more than a slight excess of hydrogen peroxide is used. 

Calcium Hypochlorite, also known as High Test Hypochlorite (HTH) is supplied in erystal form it is nearly 70% available chlorine. One produet, the Sanitizer (formally the Sierra Water Purifier) uses these erystals to superehlorinate the water to insure pathogens were killed off, then hydrogen peroxide is added to drive off... 

The methylene blue test can also be used to determine cation exchange capacity of clays and shales. In the test a weighed amount of clay is dispersed into water by a high-speed stirrer. Titration is carried out as for drilling muds, except that hydrogen peroxide is not added. The cation exchange capacity of clays is expressed as milliequivalents of methylene blue per 100 g of clay. 

Chemical composition The effect of carbide inclusions in aggravating attack in moist air has already been referred to, but in testing in 0-0005 M hydrogen peroxide, pH 6, at 85°C, the presence of carbide up to 0-26% by... 

To limit the total porosity of the coating, checking by the Iron Solution Value (ISV) test in which samples are immersed under standard conditions in a solution of sulphuric acid, hydrogen peroxide and ammonium thiocyanate, and the amount of iron dissolved is measured... 

Procedure. The sample solution should preferably contain titanium as sulphate in sulphuric acid solution, and be free from the interfering constituents mentioned above. The final acidity may vary from 0.75 to 1.75M. If iron is present in appreciable amounts, add dilute phosphoric(V) acid from a burette until the yellow colour of the iron(III) is eliminated the same amount of phosphoric(V) acid must be added to the standards. If alkali sulphates are present in the test solution in appreciable quantity, add a like amount to the standards. Add 10 mL of 3 per cent hydrogen peroxide solution and dilute the solution to 100 mL in a graduated flask the final concentration of Ti may conveniently be 2-25 parts per million. Compare the colour produced by the unknown solution with that of standards of similar composition by any of the usual methods. 

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