Reagent paper

Chloride Determine as directed in the Chloride Limit Test under Chloride and Sulfate Limit Tests, Appendix IIIB, using 100 mg of sample dissolved in 100 mL of water. Any turbidity produced by a 10-mL portion of this solution does not exceed that shown in a control containing 20 (ig of chloride (Cl) ion. Cyanide Dissolve 10 mg of copper sulfate in a mixture of 8 mL of water and 2 mL of 6 IV ammonium hydroxide. Wet a strip of filter paper with this solution, and place the wet paper in a stream of hydrogen sulfide. When 1 drop of a 1% solution of the sample is placed on the brown reagent paper, no white circle appears. 

Where high temperatures or glowing are necessary for the evolution of the gas, a simple hard glass tube supported in a circular hole in an asbestos or uralite plate (Fig. 11.58) may be used. The open end of the tube should be covered by a small piece of reagent paper and kept in position by means of a glass cap. 

Place a drop of the test solution upon the reagent paper hold it for a short time over a bottle containing concentrated ammonia solution and then over glacial acetic acid until the blue colour (ammonium quinalizarinate) first formed disappears and the unmoistened paper regains the brown colour of free quinalizarin. A red-violet or red spot is formed. 

The reagent paper is prepared by soaking quantitative filter paper in a solution obtained by dissolving 0 01 g quinalizarin in 2 ml pyridine and then diluting with 18 ml acetone. 

Ammonium was tested for in preliminary test 6 (Section V.2). By heating the original substance with NaOH solution, NH3 will be evolved from ammonium salts. The NH3 gas may be identified by its odour, by its action upon red litmus paper or upon filter paper moistened with mercury(I) nitrate solution, or by the tannic a cid-silver nitrate test (Section III.38, reaction 7). The insertion of a loose plug of cotton wool in the upper part of the tube will eliminate the danger of NaOH solution spray affecting the reagent paper. 

If ammonium is absent, add about 10 mg of Devarda s alloy (or of aluminium as powder or thin foil) and 0-2-0-3 ml sodium hydroxide solution to the reaction mixture from test 5, introduce the filter tube carrying the reagent paper and proceed as above. 

Reagent papers are made use of in the qualitative analysis of metal ions. Frequently it is necessary to know the be-... 

When determining sensitivity with alkali, the water used for diluting should be completely free from carbon dioxide. Otherwise too low a sensitivity is found. It is obvious from the above data that azolitmin paper prepared from 0.1 % indicator solution is the most sensitive reagent paper for strong acids and bases. The presence of 10 N hydrochloric acid and sodium hydroxide can be demonstrated readily with this paper. It is best also for weaker acids and bases. 

Ryles, R.G., 1983. Elevated temperature testing of motility-control reagents. Paper SPE 12008 presented at the SPE Annual Technical Conference and Exhibition, San Francisco, 5-8 October. 

Pole Reagent Paper. Unsized paper impregnated with a win of 1-2 g phenolphthalein in 10 ml alcohol and 110 ml water and then passed, while still wet. through a soln of 20 g NajSO, (cryst) in 100 ml water the paper is then dried. 

Potassium phosphate dibasic reagent, paper size pretreatment a-Amylase... 

Neutral or weakly acidic test soln placed on reagent paper... 

Test soin containing interfering oxidants taken to dryness, heated to 400-500°C and redissolved in water. Test soin is added to the reagent Neutral or acetic acid test soin dropped on the reagent paper... 

Take neutral or weakly acidic test soin to dryness with a drop of 2% CdCl2 soin. Heat on a microbumer, while covered with reagent paper Sample mixed with reagent (1) in a small porcelain dish... 

Heat with sample in a microtest tube cover mouth of tube with lead acetate paper Heat sample in microtest tube at 150°C cover mouth of tube with reagent paper. After several min hold reagent paper over ammonia vapor Mix reagent (1) and 1 drop of ethanol. Heat to ISO-ISO C for 1-2 min. After cooling add a drop of reagent (2). Examine on filter paper... 

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