1、Designation: D890 98 (Reapproved 2008) D890 12Standard Test Method forWater in Liquid Naval StoresPine Chemicals1This standard is issued under the fixed designation D890; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the quantitative determination of dissolved or occluded water present in any proportion in li
3、quidnaval stores,pine chemicals, such as turpentine, pinene, dipentene, pine oil, tall oil, and tall oil fatty acids. Three methods ofmoisture testing are included. The Karl Fisher titration method is the preferred method for testing tall oil, Test Methods D803.1.1.1 The Karl Fischer Titration metho
4、d is based on the reaction between water and a complex reagent2 consisting of iodine,sulfur dioxide, pyridine, and methanol, whereby the iodine is converted to a colorless compound. The appearance of a persistentiodine color in the reaction mixture indicates the complete removal of free water by rea
5、ction with the reagent, and the endpointmay be measured colorimetrically. Automatic titrators find this endpoint by the restoration of a current strength when the resistanceprovided by the presence of water is eliminated. Amperometric automatic titrators find this endpoint by detecting the current f
6、lowthat occurs once water is eliminated.1.1.2 The coulometric titration method determines water content by electronic integration of a current sufficient to generate theprecise amount of iodine from the required reagent to react with the water in the sample.1.1.3 The azeotropic method utilizes the r
7、elatively low boiling point of water, as compared with other sample constituents, ina toluene or xylene matrix so that water is collected in a trap and measured.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This stan
8、dard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 AST
9、M Standards:3D803 Test Methods for Testing Tall OilD1364 Test Method for Water in Volatile Solvents (Karl Fischer Reagent Titration Method)3. Significance and Use3.1 Many naval storespine chemical products contain water as a result of the processes used for their production. Typicallyrefined product
10、s such as terpenes, pine oil, tall oil fatty acids, and distilled tall oil contain only traces of water, but crude tall oilmight contain 0.5 to 2.5 % of water. Although the Karl Fischer and coulometric methods are most applicable to low levels ofmoisture, these can be and are used at higher levels.
11、The azeotropic distillation method is generally used at higher levels.1 This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.34 on Naval StoresPine Chemicals and Hydrocarbon Res
12、ins.Current edition approved June 1, 2008Nov. 1, 2012. Published June 2008December 2012. Originally approved in 1946. Last previous edition approved in 20032008 asD890 - 98 (2003).(2008). DOI: 10.1520/D0890-98R08.10.1520/D0890-12.2 This procedure has been adapted from the method of Karl Fischer publ
13、ished in Zeitschrift fr Angewandte Chemie, Vol 48, 1935, p. 395; Chemical Abstracts, Vol 29,1935 p. 6532; as modified by Smith, Bryant, and Mitchell, Journal, Am. Chemical Soc., Vol. 61, 1939, p. 2407; and further modified by Axel Johansson, SvenskPapperstidning, Vol 50, No. 11B, 1947, p. 124; see a
14、lso Publication 19 of the Swedish Wood Research Institute, Wood Chemistry and Paper Technique (Stockholm) (1947).Karl Fischer reagent is available from various laboratory supplies. Pyridine-free adaptations of the Karl Fischer reagent are available commercially.3 For referenced ASTM standards, visit
15、 the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standa
16、rd an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM
17、is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Moisture By Karl Fischer Titration(Preferred method)4. Apparatus4.1 Titration Vessel, preferably closed, with stirring capabilities,4.2 Buret, c
18、apable of being read at 0.1 mL divisions, or automatic buret, or4.3 Automatic Karl Fischer titrator.4.4 Balance, capable of weighing to the nearest 0.0001 g.5. Reagents5.1 Karl Fischer Reagent, or Other Suitable Reagent, such as Pyridine-free Adaptations of Karl Fischer Reagent . Reagentsvary in str
19、ength (titer). This test method is written assuming a titer of 5 mg water/mL reagent. Recommended additions of waterin this test method may need to be adjusted depending on the titer of the reagent.5.2 MethanolACS grade.6. Standardization of Iodine Reagent6.1 Add methanol to the titration vessel, an
20、d titrate with reagent until the lemon-yellow color just changes to a red-brown color,or, if an automatic titrator is used, until the readings indicate no free water present. The titration vessel is now ready for titrating,and is considered conditioned.6.2 Add a drop of water, weighed to the nearest
21、 0.0001 g, to the titration vessel by use of a transfer pipet, or a weighing pipet,weighing the pipet before and after the addition. Each drop will weigh approximately 0.03 g and will require roughly 6 mL oftitrant having a titer of 5 mg/mL. Alternatively, a 25-L, or other volume syringe may be used
22、 to introduce exact volumes.6.3 Titrate with reagent until the lemon-yellow color just changes to a red-brown color, or, if an automatic titrator is used, untilthe readings indicate no free water present. Record the mL of titrant used.6.4 Calculate the water equivalent of the iodine reagent, in mill
23、igrams of water per millilitre of reagent, as follows:T 5W 31000V (1)where:where:T = water equivalent of the iodine reagent, mg/mL,W = weighed water added, in g, andV = iodine reagent, mL.7. Procedure7.1 Condition the titration vessel, as described in 6.1.7.2 Add an amount of sample which will conta
24、in 50 mg or less water to the titration vessel.7.3 Titrate to a red-brown color end point, as with previous titrations, or, if an automatic titrator is used, titrate according to theinstruments operating instructions.8. Calculation8.1 Calculate the percentage of water as follows:Water, %5 V 3TW 310
25、(2)where:where:V = iodine reagent required for the titration of the sample, in mL,T = (titer), water equivalent of the iodine reagent, andW = sample used, g.8.2 Report to the nearest 0.01 %.9. Precision and Bias9.1 The precision and bias of this test method for measuring water content of the most hi
26、ghly refined naval storespine chemicalproducts are essentially as specified in Test Method D1364. It is not practical to measure the precision for moisture content ofD890 122Naval Storespine chemical products, since these test methods are applicable to many of these products that vary widely in puri
27、ty,and the precision would vary with the purity of each product.Moisture By Coulometric Titration10. Apparatus10.1 Coulometric Karl Fischer Titrator.10.2 Sample Vials, 8-mL or 4-dram10.3 Medicine Dropper.10.4 Disposable Plastic Syringes , Syringes, 1-cc with 16, 18 or 20 gage needles.10.5 Syringe, 1
28、0 L11. Reagents11.1 See 5.1.12. Instrument Preparation12.1 Prepare and calibrate the instrument according to the manufacturers operating instructions. This generally includes:12.1.1 Clean and assemble the titration chamber.12.1.2 Pour titration solution into the chamber.12.1.3 Add the iodine generat
29、or solution to the generator assembly.12.1.4 Put the instrument in the STANDBY position.12.1.5 Slowly add water, or a solution containing water, (normally by injection with a syringe).12.1.6 Continue the addition until the instrument indicates that excess water is present, usually by a light or liqu
30、id crystal display(LCD) reading.12.1.7 Stop the addition of water.12.1.8 Let the instrument stabilize for 1 h in the STANDBY position.12.2 Verify the instrument by injecting a known amount of water, usually 1 L to 5 L, below the surface of the titrationsolution.12.3 Put the instrument in the TITRATE
31、 or RUN position and record the reading when the END light comes on or a messageappears that the titration is complete.12.4 Record the reading. This reading is usually in micrograms or milligrams of water and should be within 65 % of the amountof water added. Example: for 5 L of water the reading sh
32、ould be 5000 g 6 250 g.13. Procedure13.1 Some coulometric titrators require that the sample be injected through a septum. If this is the case proceed as follows (forinstruments that do not require through-septum injections, go to 13.2):13.1.1 Draw approximately 0.5 mL of sample into a 1-cc disposabl
33、e syringe. Wipe the needle clean with a dry paper towel.13.1.2 Weigh the syringe with the sample to the nearest 0.0001 g. Record this weight.13.1.3 Inject about 0.1 to 0.2 mL of the sample into the titrator. Withdraw the syringe.13.1.4 Weigh the syringe to the nearest 0.0001 g and record this weight
34、.13.1.5 Proceed to 13.6.13.2 Add approximately 4 mL of sample in a small sample vial. Do not allow the sample to touch the outside of the vial.13.3 Put a medicine dropper into the vial, and weigh the vial, sample, and medicine dropper together on an analytical balanceto the nearest 0.0001 g. Record
35、this weight.13.4 Using the medicine dropper, introduce one to two drops of sample into the coulometric titrator.13.5 Put the medicine dropper back in the vial, and weigh to the nearest 0.0001 g. Record this weight.13.6 Begin the titration.14. Calculation14.1 Calculate the percentage of water as foll
36、ows:Water, %5 Water, gSample Weight, g310 000 (3)14.2 Report to the nearest 0.01 %.D890 12315. Precision and Bias15.1 It is not possible to specify the precision of this coulometric titration procedure for measuring the water content of navalstorespine chemical products because the procedure is not
37、widely used and insufficient data could be generated to develop ameaningful precision and bias statement.Moisture By Azeotropic Distillation16. Apparatus16.1 Flask, 1-L, short-neck, round-bottom glass flask or Erlenmeyer flask. Use of smaller flasks should be accompanied byreductions in sample size
38、and solvent.16.2 Electric Mantle, with variable-resistance controller.16.3 Condenser, connected to the flask and discharging into a trap.16.4 Trap, 5-mL, subdivided into 0.1 mL divisions, with each 1 mL line numbered.17. Reagents17.1 Toluene or XyleneReagent grade, moisture free.18. Procedure18.1 We
39、igh 100 g of sample into the flask. Add a few boiling stones. Fit the flask with a moisture trap and a reflux condenser.18.2 Add 150 mL of toluene or xylene to the flask and fill the moisture trap with the solvent.18.3 Heat gently until the solvent begins to reflux. Continue vigorous refluxing for 2
40、 h. Wash the condenser down with 5-mLportions of solvent from time to time during the reflux period, and with four 5-mL portions of solvent at the end. A drop of wateron the condenser may be dislodged with a fine wire or a stirring rod wet with methanol.18.4 Record the volume of water in the trap.19
41、. Calculation19.1 Calculate the percentage of water as follows:Water, %5 VW 3100 (4)where:where:V = volume of water, mLW = weight of sample, g.19.2 Report to the nearest 0.1 %.20. Precision and Bias20.1 It is not possible to specify the precision of this azeotropic distillation procedure for measuri
42、ng the water content of navalstorespine chemical products because this procedure is no longer widely used and insufficient data could be generated to developa meaningful precision and bias statement.D890 12421. Keywords21.1 azeotropic; coulometric, Karl Fischer; moisture; naval stores; pine oil;chem
43、icals; pine oil; tall oil; terpenes; turpentine;waterASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent ri
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45、r revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearin
46、g you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D890 125
