1、 FORD LABORATORY TEST METHOD AK 115-01 Date Action Revisions 2001 01 22 Revised Editorial no technical change A. Cockman 2000 03 23 Revised Editorial no technical change A. Cockman 1990 06 12 Printed copies are uncontrolled Page 1 of 4 Copyright 2001, Ford Global Technologies, Inc. QUANTITATIVE ANAL
2、YSIS OF CHLORIDES IN CLEANERS Application This test method is used to determine the percent chlorides in cleaners. Apparatus Required Hot Plate Oven Mechanical convection: Must be capable of heating to 150 C as well as maintaining 105 +/- 2 C for 15 minutes. Bunsen or Meeker Burner Fritted Glass Cru
3、cible with a Glass Microfiber Filter A Gooch crucible may also be used. (Whatman No. 934-AH) Analytical Balance Precision +/- 0.1 mg Beaker 250 mL Watch Glass Suitable for 250 mL beaker Buret or Pipet Suction Flask The above apparatus is available from any reputable laboratory equipment supply house
4、. Materials Required Nitric Acid Concentrated, reagent grade. Caution: Corrosive FORD LABORATORY TEST METHOD AK 115-01 Page 2 of 4 Copyright 2001, Ford Global Technologies, Inc. Silver Nitrate Reagent grade Distilled or Deionized Water 20 micromhos/cm at 25 C maximum conductivity (ASTM D 1125) Solut
5、ions Required Nitric Acid Solution 1:1 Nitric Acid Solution 1 % concentration (1 mL per 99 mL of distilled water) Silver Nitrate Solution 10 % concentration Silver Nitrate Solution 0.05 g/L Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a contr
6、olled atmosphere of 23 +/- 2 C and 50 +/- 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. Procedure A. Gravimetric Method 1. Take a 0.5 or 1.0 g aliquot of the prepared 1 % solution of cleaner in a 250 mL beaker. 2. Dilut
7、e to 200 mL with distilled water. 3. Add 10.0 mL of 1:1 nitric acid and boil on hot plate for 15 minutes. (a) If nitrites are present, an excess of nitric acid must be used. (b) Boiling must also be used to drive off the fumes of NO2. (c) Cool solution after this boiling. This will eliminate loss of
8、 chloride due to a possible spattering. FORD LABORATORY TEST METHOD AK 115-01 Page 3 of 4 Copyright 2001, Ford Global Technologies, Inc. 4. Add 10 mL of 10 % silver nitrate solution to the beaker after step 3. Add the silver nitrate from a buret or pipet, drop by drop using the 10 mL, stirring the s
9、olution during the addition. Allow the precipitate to settle and add a few more drops of reagent (AgNO3) and continue the addition as long as a precipitate forms with the reagent. Usually you have added about 20 % in excess of the reagent. 5. Heat to boiling, covering the beaker with a watch glass.
10、6. If the solution is still cloudy, stir vigorously. This will cause the finely-divided sliver chloride to coagulate and settle out so that the solution will be clear. Avoid exposing the precipitate to strong light as this will cause the exposed surface to decompose into the subchloride and liberate
11、 chlorine. 7. Filtration: B. Fritted Glass Crucible Method (or Quartz) 1. Prepare a fritted glass crucible with a glass microfiber filter and wash thoroughly with 1 % nitric acid solution. 2. Dry the crucible with the filter in an over at 100 C, then heat gently over a free blue flame. Cool in desic
12、cator and weigh. 3. Wash the silver chloride, first by decantation, then transfer to the crucible which has been placed in position on a suction flask. Gentle suction is applied and the precipitate is washed free by repeated additions of the wash water containing the nitric acid. 4. Place the crucib
13、le in an oven for 15 minutes or more and dry at 105 C. Now heat to 130 150 C to expel water. Cool in a desiccator. 5. Weigh. The weight in excess of that due to the crucible is due to silver chloride. 6. Calculate percent chlorine from the weight of sample taken. Note: (a) The silver chloride may be
14、 removed from the crucible by adding a piece of zinc and dilute sulfuric acid to the residue. (b) AgCl is soluble in ammonium hydroxide solution. FORD LABORATORY TEST METHOD AK 115-01 Page 4 of 4 Copyright 2001, Ford Global Technologies, Inc. (c) Owing to the slight solubility of AgCl, it has been r
15、ecommended to wash first with water containing AgNO3 (0.05 g/L), then with 1 % solution of nitric acid and finally with pure distilled water. (d) If chloride content is below 0.5 %, volumetric analysis should be used. Factors to use for calculations: (1) Weight AgCl x .24737 x 100 = % Cl Weight sample (2) % Cl x 1.6485 = % NaCl (3) % Cl x 2.1029 = % KCl (4) % Cl x 1.5088 = % NH4 Cl Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities.
