1、ANSI PHLI.234 86 07241150 CIOLL354 2 M 19 ANSI PH4.234-1986 Revision of ANSI PH4.234-1980 American National Standard for photography (chemicals) - trisodium phosphate, dodecahydrate Approved October 16, 1986 Secretariat: National Association of Photographic Manufacturers, I nc Warning and Safety Pre
2、cautions Some of the chemicals specified in the test proce- dures in this standard are corrosive, toxic, or otherwise hazardous. Specific caution, warning, and danger notices are given in the footnotes but, in addition, the normal precautions required dur- ing the performance of any chemical procedu
3、re must be exercised at all times. It is recommended that anyone using these chemicals obtain from the manufacturers pertinent information about the hazards, handling, and use of these chemicals. Such information is usually furnished by the chemicalmanufacturer in the form of a material safety data
4、sheet. I Page 1 of 4 pages Introduction (This Introduction is not part of American National Standard PH4.234-19 86 .) This standard is one of a series that establishes criteria of purity for chemicals used in processing photographic materials. Although the ultimate criterion for suitability of a pho
5、tographic-g;ade chemical is its successful perfor- mance in an appropriate test, the shorter, more eco- nomical tests described herein are generally adequate. This standard is a revision of American National Standard Specification for Photographic Grade Triso- dium Phosphate, Dodecahydrate, (Na3P04
6、12H20), NaOH), ANSI PH4.234-1980. In this latest revision, the section on “Physical Appearance” has been re- placed with a section on “General Information.” The section on “Reagents for Test Methods” has been re- named “Reagents, Materials, and Glassware.” Strength of standard solutions is now expre
7、ssed as molarity. Also, minor changes in precaution notations have been made, and the general format has been changed to be in agreement with the style outlined in the Directives for the Technical Work of the International Organiza- tion for Standardization (ISO). An American National Standard impli
8、es a consensus of those substantially concerned with its scope and provisions, An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general public. The existence of an American National Stan- dard does not in any respect preclude anyone, whether he has
9、approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standard. American National Standards are subject to periodic review and users are cautioned to obtain the latest editions. The American National Standards Insti
10、tute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shaii have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. CAUTION N
11、OTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of ap- proval, Purchasers of American Nationa
12、l Standards may receive current information on all standards by calling or writing the American Na- tional Standards Institute. 0 1987 by American National Stand- 1430 Eroadwav. New York, N.Y, I0018 ANSISC187/4 *I ANSI PH4.234 Bb B Il724350 0033355 4 Page 2 of 4 pages i. Scope This standard establis
13、hes criteria for purity of photo- graphic-grade trisodium phosphate, dodecahydrate and describes the tests to be used to determine the purity. 2. General Information 2.1 Physical Properties. Trisodium phosphate, dodeca- hydrate exists in the form of colorless or white crystals. The chemical formula
14、is Na3P04 12H20 and the rela- tive molar mass is 380.12. 2.2 Hazardous Properties. Trisodium phosphate, do- decahydrate, is a strong base. It is corrosive. Contact with skin and eyes should be avoided. The dust should not be inhaled. 2.3 Handling and Storage Conditions. No special pre- cautions are
15、required for handling and storage of tri- sodium phosphate, dodecahydrate, beyond those that are applicable to any chemical material. 3. Summary of Requirements Assay (as Na,P04 12H20) 98.0% (m/m) minimum* Excess alkali (as NaOH) 2.5% (m/m) maximum Insoluble matter 0.02% (m/m) maximum Halides (as CI
16、) 0.05% (m/m) maximum Heavy metals (as Pb) 0.001% (m/m) maximum Iron (Fe) 0.001% (m/m) maximum Appearance of solution To pass test *This salt, when stored under ordinary conditions, may lose some water of crystallization. Any loss in water wi result in an assay of more than 100% Na,P04*12H,O but doe
17、s not affect the determination of the relative amount of free alkali present. NOTE: m/m = mass per mass (weight per weight) 4, Reagents, Materials, and Glassware 4.1 Reagents 4.1.1 Reagents shall be handled in conformity with health and safety precautions, as shown on containers or as given in other
18、 sources of such information. Proper labeling of prepared reagents includes name, date of preparation, expiration date, restandardization date, and adequate health and safety precautions. The dis- Sold under names such as sodium phosphate, tribasic, dodeca- hydrate; trisodium orthophosphate, dodecah
19、ydrate; TSP. posa1 of reagents and all materials shall conform to ap- plicable environmental regulations. 4.1.2 Reagents used in the test procedures shall be certified reagent-grade chemicals and shall meet the specifications given in Reagent Chemicals2 published by the American Chemical Society (AC
20、S) in 1981, or chemicals of a purity acceptable for the analysis. The acids and ammonia solutions referred to in all the instructions shall be of full strength unless dilution is specified. Dilution is specified in terms of molarity, M, when standardization is required. The number of sig- nificant f
21、igures to which molarity is known shall be sufficient to ensure that the reagent does not limit the reliability of the test method. When dilution is indi- cated as (1 t X), it means that one volume of the speci- fied reagent is added to X volumes of distilled water. 4.2 Water. Whenever water is spec
22、ified in the test pro- cedures, only distilled water or water of at least equal purity shall be used. 4.3 Glassware, All glassware subject to heating shall be of heat-resistant glass; for example, Pyrex or equiva- lent. 5. Test Procedures The test procedures described in Sections 6 through 12 shall
23、be followed to determine whether the test samples meet the purity requirements listed in Section 3. Tests shall be made in their “as received” condition. In the last several years, there have been great im- provements in instrumentation for various analyses. Where such techniques have the equivalent
24、 accuracy and precision, they may be used in place of the tests described in this standard. 6. Assay 98.0% (m/m) minimum, Na3P04 12H20 6.1 Reagents (36.46 g/L). An analyzed reagent solution is recom- mended. This is commercially available from several vendors. 6.1.2 Standard Sodium Hydroxide Solutio
25、n, Free of Carbonate 1.0 M (40.00 g/L). An analyzed reagent solution is recommended. This is commercially avail- able from several vendors. 6.1.1 Standard Hydrochloric Acid Solution, 1 .OM I 0 Available from American Chemical Society, 1155 Sixteenth Street, NW, Washington, DC 20036. ANSI PH4.234-198
26、6 6.2 Apparatus. In addition to ordinary laboratory apparatus, the following equipment shali be used: (1) pH meter with a glass electrode system (2) Buret, straight-type Pyrex or equivalent, with Teflon0 stopcock, 50-mL capacity 6,3 Procedure. Weigh 13 to 14 grams of the sample to the nearest 0.001
27、gram and dissolve in 40 mL of water in a 400-mL beaker. Add 100.0 mL of 1 M hydrochloric aid, and pass a stream of carbon- dioxide-free air, in fine bubbles, through the solu- tion for 30 minutes to expel carbon dioxide. The beaker shail be covered to prevent loss of any of the solution by spraying.
28、 Wash down the cover and sides of the beaker. Titrate the solution with 1 M sodium hydroxide4 (6.1.2) to a pH of 4.00 as mea- sured with a standardized pH meter and glass elec- trode system. Calculate (A) the milliliters of 1 M hydrochloric acid consumed in this titration. Pro- tect the solution fro
29、m absorbing carbon dioxide from the air and continue the titration to pH 8.80 with 1 M sodium hydroxide. Calculate (B) the milli- liters of 1 M sodium hydroxide consumed in this titration. If A is equal to or greater than 2B, then B X 0.3801 X 100 - -,. - _ _- _ - I If A is less than 2B, then (A Wei
30、ght of sample X 100 = Na3P04 12H20 7. Excess Alkali 2.5% (m/m) maximum as NaOH Calculate the amount of excess alkali as NaOH from the titration values obtained in the test for assay. If A is equal to or less than 2B, there is no excess alkali present when the salt is dissolved. If A is greater than
31、2B, then 3DANGER: Harmful if inhaled. Avoid breathing dust, vapor, mist, and gas. Use only with adequate ventilation. If inhaled, move to fresh air. Obtain medical attention immediately, skin, and clothing# Use with adequate ventilation. In case of contact, flush with water. Obfain medical attention
32、 immedi- ately. I DANGER: Corrosive, causes burns. Avoid contact with eyes, Page 3 of 4 pages 8. Insoluble Matter 0.02% (m/m) maximum 8.1 Reagent -Methyl Red Indicator Solution. Dissolve 0.10 gram of methyl red, o- p(Dimethylamino)phe- nyl azo benzoic acid, in 100 mL of methanl., 8.2 Procedure. Diss
33、olve 5 grams of the sample in 100 mL of water, add 0.1 mL of methyl red indicator solu- tion (gal), and add hydrochloric aid, until the solu- tion has turned to a faint pink. Heat the solution to boiling and digest in a covered beaker on the steam bath for 1 hour. Filter through a tared filtering cr
34、ucible, wash thoroughly, and dry at 105C, cool in a desicca- tor, and weigh, The weight of the residue shall not ex- ceed 0.010 gram. 9. Halides O.OS% (m/m) maximum as Ci 9.1 Halide Standard (1 mL = 0.005 mg Ci). Dissolve 0.33 gram of sodium chloride in water, dilute to 1 liter, and mix weii. Dilute
35、 a 25-mL aliquot of this solution to 1 liter, and mix well. 9.2 Procedure. Dissolve 1 .O gram & 0.1 gram of the sample in water and dilute to 100 mL with water. Acidify a IO-mL aliquot with 10 mL of dilute nitric acid4 (1 t 9), add 1 mL of silver nitrate slution, (100 g/L), dilute to 50 mLwith water
36、, and mix well. Any turbidity produced shaii not exceed that produced by 10 mL of the Halide Standard (9.1) treated in the same manner as the aliquot. Use Nessler color compari- son tubes for comparison. 10. Heavy Metals 0.001% (m/m) maximum as Pb 10.1 Reagents Dissolve 1.8 grams of lead acetate, tr
37、ihydrate Pb (C2H3 O,) 3H2 O in 900 mL of water in a 1 -liter volumetric flask. Dilute to 1 liter with water and mix weil. Dilute a 10-mL aliquot to 1 liter with water, and mix well. 10.1.1 Heavy Metals Standard (1 mL = 0.01 mg Pb). DANGER: Flammable, keep away from heat, sparks, and open flame. Use
38、with adequate ventilation. DANGER Poison.May be fatal or cause blindness if swal- lowed. Harmful if inhaled. If swallowed, induce vomiting. Ob- tain medical attention immediately. WARNING: Harmful if inhaled, Avoid breathing dust. Use only with adequate ventilation. If inhaled, move to fresh air. Ob
39、tain medical attention immediately. ANSI PH4.234-1986 ANSI PH4.23L1 8b W 0724350 0033357 8 Page 4 of 4 pages 10.1.2 Iron Standard(1 mL = 0.01 mg Fe). Dissolve 0.70 gram of ferrous ammonium sulfate, hexahydrate Fe(NH4)2(S04)2 *6Hz0 in 50 mL of water in a 1-liter volumetric flask. Add 20 mL of dilute
40、sulfuric acid4 (1 t 15). Dilute to 1 liter with water, and mix well. Dilute a 10-mL aliquot of this solution to 100 mL with water, and mix well. 10.1.3 p-Nitrophenol Indicator. Dissolve 0.25 gram of p-nitrophenol in 100 mL of water. 10.1.4 Sodium Sulfide Solution. Dissolve 5 grams of sodium sulfide,
41、 nonahydrate3 (Naz S* 9Hz O) in 100 mL of water. 10.2 Procedure. Dissolve 5.0 grams of the sample in approximately 25 mL of water in a 100-mL beaker. Pipet 5.0 mL of the Heavy Metals Standard (10.1.1) into a second 100-mL beaker containing 20 mL of water, Into a third 100-mL beaker containing 20 mL
42、of water, pipet 5.0 mL of the Iron Standard (10.1.2). Treat the two standard solutions and the sample solu- tion as follows: Add 2 drops of paitrophenol indicator (10.1.3) and then add, dropwise, dilute hydrochloric Add dilute ammonium hydrxide, (1 t 9) dropwise until the solution turns yellow. Add
43、dilute hydrochloric aid, (1 t 99) dropwise until the solution becomes colorless, and then add 0.5 mL excess. Warm on a steam bath for 10 minutes. Cool, dilute to 50 mL with water, and mix weil. To 20-mL aliquots of the solution containing the Heavy Metals Standard and the sample solution (save the s
44、olution containing the Iron Stan- dard and the balance of the sample solution for the iron test in Section 1 l), add i drop of sodium sulfide3 (10.1,4), dilute to 50 mL with water, and transfer to Nessler color comparison tubes for comparison, Any color produced in the sample solution shall not exce
45、ed that produced in the treated Heavy Metals Standard solution. (1 t 3) until the solution becomes colorless. 11. Iron 0.001% (m/m) maximum Fe 11.1 Reagents drous sodium acetate to 60 mL of dilute acetic acid4 (1 t 8), and dilute to 1 liter with water. Adjust the final pH of the solution to 5.0 f 0.
46、1 with acetic acid4 or sodium hydroxide solution4 (100 g/L). 11.1.2 1 ,lo-Phenanthroiine (o-Phenanthroline) Mixture. Thoroughly mix equal parts of an aqueous solution of 1,lO -phenanthroiine (1 g/L), a solution of hydroxylamine hydrochlorides (100 g/L), and pH 5 acetate buffer. 11.2 Procedure. To 20
47、-mL aliquots of the Iron Stan- dard and the sample solution prepared in 10.2, add 5 mL of the 1 ,lo-phenanthroline mixture (10.1,2), mix well, and let stand for ten minutes, Dilute to 50 mL with water, mix well, and transfer to Nessler color comparison tubes for comparison. Any color pro- duced in t
48、he sample solution shall not exceed that pro- duced in the treated Iron Standard solution. 11.1.1 pH 5 Acetate Buffer. Add 23 grams of anhy- 12. Appearance of Solution (To pass test) A solution Containing 200 grams of the sample per liter in water shall be clear and colorless and free from sedi- ment other than a slight flocculence. WARNING: Avoid contact with eyes, skin, and clothing. Wash thoroughly after handling. In case of contact, flush eyes and skin with water. Obtain medical attention immediately. L ANSI PH4.234-1986 -/-
