Antimony test procedure

Biological responses are typically dependent on a number of test parameters Including state of the tested material (solid or In solution), solvent, organism and test procedure. Since test results are dependent on these variables. It Is advantageous to associate testing conditions with an Intended application. Much of our research with polymers containing tin, antimony and arsenic Is associated with control of mildew and rot for eventual application In topical medications, as thermal Insulation and as additives In paints, textiles and paper products. 

Two methods are used to measure pH electrometric and chemical indicator (1 7). The most common is electrometric and uses the commercial pH meter with a glass electrode. This procedure is based on the measurement of the difference between the pH of an unknown or test solution and that of a standard solution. The instmment measures the emf developed between the glass electrode and a reference electrode of constant potential. The difference in emf when the electrodes are removed from the standard solution and placed in the test solution is converted to a difference in pH. Electrodes based on metal—metal oxides, eg, antimony—antimony oxide (see Antimony AND ANTIMONY ALLOYS Antimony COMPOUNDS), have also found use as pH sensors (8), especially for industrial appHcations where superior mechanical stabiUty is needed (see Sensors). However, because of the presence of the metallic element, these electrodes suffer from interferences by oxidation—reduction systems in the test solution. 

The AO AC (978.42) recognizes a similar procedure, except that the unsap onitiable material is treated with maleic anhydride to remove the trans-isomer which may possibly be present (83). The antimony trichloride colorimetric assay is performed on the trans-isomer-free material. This procedure cannot be used to distinguish certain inactive isomers, eg, isotachysterol if present, these are included in the result, giving rise to a falsely high analysis. A test must therefore be performed to check for the presence of isotachysterol. 

Antimony Oxychloride. Pour the first portion of the distillate saved from the above procedure into 2 liters of water. Stir, allow to settle, and draw off the clear liquid. Stir up with water once more, let settle, draw off as much of the water as possible, and drain the precipitate on a suction filter. Dry it on paper towels and put it up in a cork-stoppered test tube. 

Procedure, A small quantity of the sample is placed in a micro test tube and a ten-fold excess of either ammonium chloride or bromide is added. After mixing, the contents of the test tube are heated cautiously over a low flame so that the sublimate forms about 1-2 cm above the bottom of the test tube. Cool and, with the aid of a glass rod, touch the sublimate zone with a piece of cotton moistened with a few drops of a 1 1 mixture of 16 Af NaOH and 5 % aqueous Hg(CN)2 solution. Elemental antimony is indicated by the appearance of a black smudge or zone on the cotton. 

Procedure. A drop of the test solution is placed on filter paper impregnated with a 5 % aqueous solution of phosphomolybdic acid, and held over steam. In a few minutes a blue coloration appears it is more or less intense according to the amount of antimony present. 

Procedure. One ml of the dyestuff solution is treated on a spot plate with a drop of the test solution, which should be made strongly acid with hydrochloric acid, and if necessary oxidized beforehand, by sodium nitrite. In the presence of antimony, the bright red (fluorescent) dye solution changes to violet. 

Procedure. A drop of the solution to be tested is treated in a test tube with 6 drops of 1 3 sulfuric acid followed by a drop of 10 % potassium iodide solution. The solution is shaken vigorously with 1 ml of benzene. The benzene layer is removed with a pipette and placed in a depression of a spot plate. A drop of 0.2 % solution of Rhodamine B is placed in the center of the depression. The presence of antimony is indicated by the violet antimony-Rhodamine B complex... 

Antimony pentoxide and tetroxide are dissolved by strong hydrochloric acid in the presence of excess alkali iodide. Iodine is set free and Sblg or H[Sbl4] is formed. This complex acid gives a red-violet water-insoluble salt with the basic dyestuff Rhodamine B. The chemistry of this sensitive test and the procedure, which has an identification limit of 0.6 y antimony when conducted as a spot test, is discussed on page 108. 

When testing for antimony in organic compounds, a small sample is ashed in a micro crucible and the residue is treated with a freshly prepared 1 % solution of diphenylamine or diphenylbenzidine in concentrated sulfuric acid. A blue color appears at once or within several minutes if antimony is present. The limit of identification of this procedure is 5 y antimony. 

Procedure. One drop of the test solution is mixed in a micro test tube with one drop of antimony trichloride and NaOH to adjust the pH to 10. The tube is heated in a water bath at 80° C. An orange color of antimony trisulfide indicates the presence of tetrathionate. ... 

Procedure. A minimum amount of the solid test material is placed in a micro crucible or in the depression of a spot plate. When calcination is necessary, a micro crucible is preferable. One drop of 5 % potassium iodide solution, one drop of (1 1) HCl and one drop of sulfurous acid are added and mixed by blowing through a pipette. Then one drop of the 0.5 % dyestuff solution is added. When antimony is present, a violet precipitate is immediately produced. A blank test with potassium iodide and sulfurous acid is only necessary when very small amounts of antimony are to be detected. 

Sometimes a simultaneous test for tin and antimony instead of separate tests may be advantageous. The following procedure is appropriate. It is based on the fact that SnBr4 and SbBrg are formed if bromine vapors act on powdered alloys containing tin and antimony. When treated with alkali hydroxide, these bromides are converted into the corresponding hydroxides, which can be very sensitively detected with morin by the formation of fluorescing adsorption compounds. 

Tin dioxide can be detected in oxide minerals and pigments by means of the procedure given here. It may be pointed out that TiOg does not behave in a similar way and also that antimony compounds do not interfere with this test. 

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