1、Designation: D7358 07 (Reapproved 2013)Standard Test Method forWater Content of Paints by Quantitative Calcium HydrideReaction Test Kit1This standard is issued under the fixed designation D7358; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f revision, the year of 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 This test method describes the determination of the totalwater content of paints using a calci
3、um hydride reaction testkit, or water content between 2 and 85 % water.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
4、 It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD3925 Practice for Sampling Liquid Paint
5、s and RelatedPigmented CoatingsD4017 Test Method for Water in Paints and Paint Materialsby Karl Fischer MethodE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3. Summary of Test Method3.1 A0.25 mL sample is reacted with a specially formulatedcalcium h
6、ydride reagent to convert water in the sample tohydrogen gas. The reaction is carried out in a sealed pressurevessel and the resulting pressure is then measured using aspecially designed meter programmed to convert gas pressureinto water content. The results are displayed in milligrams ofwater in th
7、e reacted sample extract. The actual weight percentwater in the whole paint sample is manually calculated usingthe exact weights of the paint sample and the diluted extractsample, if used.4. Significance and Use4.1 Although Test Method D4017 is widely used for thedetermination of water in paints and
8、 related materials, thismethod may overcome some of the variability found in theKarl Fischer method.4.2 Control of water content is often important in control-ling the performance of paints, and it is critical in determiningvolatile organic compound (VOC) content when VOC contentis measured by diffe
9、rence from total volatile matter and watercontent as required in certain federal and state regulations.5. Interferences5.1 The following compounds, tested at twice the samplesize, have been found to produce no measurable response to thecalcium hydride reaction test kit and, therefore, cause nointerf
10、erence at levels up to 40 %:3EthanolMethanolAcetoneAMethyl Ethyl KetoneTetrahydrofuranDiethylene Glycol Dimethyl EtherEthylene GlycolADiethylene GlycolDipropylene GlycolStearic Acid2Ethyl Hexanoic AcidLead Oxide (II and III)Aluminum Oxide (Brockman I)A0.25 mL sample size program A and B.5.2 When usi
11、ng the 5 mL sample size programs, that is,programs C, D, or E, ethylene glycol and acids have beenfound to produce a positive result in the presence of a smallamount of water. Ethylene glycol responds at approximately7 % of the volumetric equivalent.1This test method is under the jurisdiction of AST
12、M Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1, 2013. Published June 2013. Originallyapproved in 2007. Last previous edition approved i
13、n 2007 as D7358 07. DOI:10.1520/D7358-07R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3HydroSCOUT Users
14、 Manual.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus6.1 HydroSCOUT4SystemA test kit system consisting ofthe HydroSCOUT meter, reaction tubes, sampling syringes anddilution vials.5The entire analytical sequence, includi
15、ngsampling, sample dilution, chemical reactions andquantification, is available in kit form using pre-dispensed andencapsulated reagents. An analytical balance is required inorder to obtain the most precise results. In addition, a mechani-cal shaker may be necessary to obtain a representative sample
16、.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.All reagents shall conform to the specificationsof the Committee on Analytical reagents of the AmericanChemical Society, where such specifications are available.67.2 Purity of WaterUnless otherwise indi
17、cated, referenceto water shall mean reagent water conforming to SpecificationD1193, Type II.7.3 Calcium Hydride (20 %) in HI SOL 10contained in acrushable glass ampule.7.4 Watercontained in a crushable glass ampule.7.5 Diethylene Glycol Dimethyl Ether (Diglyme)2.25 mLcontained in a glass vial.8. Haz
18、ards8.1 Store ampules in a cool, dry place. Keep away fromheat, sparks, water and open flames.8.2 See manufacturers instructions and Material SafetyData Sheet (MSDS) before use.8.3 The gray ampule in the tube contains calcium hydride,which is a flammable solid and water reactive.8.4 Perform test onl
19、y in a well ventilated area.8.5 Always wear rubber gloves and safety glasses.8.6 Take care to ensure that fingers are not cut by glass inthe kits. Each ampule should be crushed only once to reducethe risk of glass pieces piercing the sides of the tube.8.7 When venting reaction tube after completion
20、of test,point tube upright and away from user and bystander.8.8 When breaking the green water ampule after completionof test, the tube must be shaken vigorously for the full 15seconds to ensure that the water contacting the remainingcalcium hydride does not overheat the side of the tube,otherwise tu
21、be failure can result.9. Sampling, Test Specimens, and Test Units9.1 Sample CollectionTake a representative sample of theliquid coatings in accordance with Practice D3925. Mixthoroughly before taking specimens for individual tests.10. Preparation10.1 PreparationRemove a sampling syringe with capand
22、a test tube from the kit box. Check the contents to ensurethat all items are present and intact. If a dilution is to be used,remove a dilution vial and an additional sampling syringe andcap. Remove the screw cap and rubber septum from the tubeand the cap from the dilution vial, if used. Insert one g
23、reenwater ampule into the top of the polypropylene ampule sleeveand replace the holder in the tube.11. Calibration and Standardization11.1 The commercially available meter is calibrated at thefactory over the pressure range of 0 to 60 psig. Each time themeter is turned on, the pressure transducer re
24、calibrates the 0psig point. If this changes significantly from the factory setpoint, an error message will be displayed. This error will alsoappear if a tube is accidentally inserted into the meter beforethe meter is turned on.12. Procedure12.1 Sample Introduction for Expected Water Content LessThan
25、 15 % (No Dilution)Work the plunger on an emptysampling syringe a few times to ensure that it slides easily.Place the tip of the syringe into the paint sample to be testedand slowly pull back on the plunger until it reaches the stop andcannot be pulled further. Remove the syringe from the paintsampl
26、e and wipe any excess paint from the outside of thesyringe with a tissue wipe provided with the kit. Cap thesyringe with the cap provided and weigh; record the weight(gross sample weight) to the nearest 0.1 mg. Dispense thesample into the reaction tube. Recap the syringe withoutwiping, reweigh it, a
27、nd record this weight (sample tare weight).The difference in the two weights becomes the sample weight(S1) to be used in Eq 1. Replace the rubber septum (hole ontop) by gripping the tube firmly and pressing the septum downwith the thumb. (NOTE: Do not squeeze the sides of the tubewhile inserting the
28、 septum.) Replace the screw cap tightly,turning it until it cannot be turned further. Proceed to step 12.3.12.2 Sample Introduction for Expected Water ContentGreater Than 15 % (With Dilution)Work the plunger on anempty sampling syringe a few times to ensure that it slideseasily. Place the tip of the
29、 syringe into the paint sample to betested and slowly pull back on the plunger until it reaches thestop and cannot be pulled further. Remove the syringe from thepaint sample and wipe any excess paint from the outside of thesyringe with a tissue wipe provided with the kit. Cap thesyringe with the cap
30、 provided and weigh; record the weight(gross sample weight) to the nearest 0.1 mg. Dispense thesample into the dilution vial containing a premeasured amountof solvent (2.15 g). (Do not allow the syringe to contact thedilution solvent when dispensing the sample.) Recap thesyringe without wiping, rewe
31、igh it, and record this weight(sample tare weight). The difference in the two weights4HydroSCOUT is a trademark of the Dexsil Corporation.5The sole source of supply of this kit known to the committee at this time isDexsil Corporation, One Hamden Park Drive, Hamden, CT 06517. If you are awareof alter
32、native suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washi
33、ngton, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D7358 07 (
34、2013)2becomes the sample weight S1to be used in Eq 2. Replace thecap on the dilution vial and shake the vial vigorously for atleast 10 seconds. Remove the cap and quickly, using a newsyringe, draw up a sample from the solution. Wipe any excesssolution from the outside of the syringe, cap and weigh t
35、hesyringe. Record this weight (diluted sample gross weight).Dispense this sample into the reaction tube. Recap the syringe,without wiping it, and reweigh the syringe and record thisweight (diluted sample tare weight). The difference in the twoweights becomes the diluted sample weight (S2) to be used
36、 inEq 2. Replace the rubber septum (hole on top) by gripping thetube firmly and pressing the septum down with the thumb.(NOTE: Do not squeeze the sides of the tube while insertingthe septum.) Replace the screw cap tightly, turning it until itcannot be turned further.12.3 ReactionBreak the bottom (gr
37、ay) ampule in the tubeby compressing the sides of the tube. Mix thoroughly byshaking the tube vigorously for 30 seconds. The mixture willbe seen to bubble and perhaps foam. Allow the reaction toproceed for 2 minutes. Shake the reaction tube again for 10seconds and let stand for an additional 1 minut
38、e.12.4 AnalysisEnsure the meter is set for the correctprogram for determining water in paint and that the meter isready for measurement. Insert the reaction tube firmly into theopening at the bottom of the meter. The hole in the white capmust be lined up with the metal pin extending from the insideo
39、f the hole in the meter. Press the “READ” button on the faceof the meter. The display will flash the word “CALC,” then theresults will be displayed in milligrams of water in the sample.Record the results. Keep the meter and tube upright at all times.12.5 DisposalCarefully remove the reaction tube fr
40、om themeter. Vent tube by inserting completely into venting cap andremoving. Tube and cap must be upright and pointed awayfrom user and bystanders. Tap the tube on the bench top toshake any loose glass to the bottom of the tube, then break thetop (green) ampule in the reaction tube by compressing th
41、esides of the tube. Shake the tube for 15 seconds.After any foamhas settled, vent the tube again. Discard the tube and vial aslaboratory waste. Do not remove cap.13. Calculations13.1 Calculations for Direct Sample (No Dilution) Themeter is programmed to display the weight, in milligrams, ofthe water
42、 contained in the sample introduced into the reactiontube (in this case the paint sample). Calculate the water contentin the original paint sample in weight percent using Eq 1:Water in paint, wt. percent 5 R/10*S1! (1)where:R = meter reading in milligrams of waterS1= actual weight of whole paint sam
43、ple, grams13.2 Calculations for Diluted Sample (With Dilution)Themeter is programmed to display the weight, in milligrams, ofthe water contained in the sample introduced into the reactiontube (in this case the diluted sample). Calculate the watercontent in the original paint sample in weight percent
44、 using Eq2:Water in paint, wt. percent 5 R/S2!112.15/S1!/10 (2)where:R = meter reading in milligrams of waterS1= actual weight of whole paint sample, gramsS2= actual weight of diluted paint sample, grams2.15 = weight of the dilution solvent, grams14. Report14.1 Report calculated water content in wei
45、ght percent tothree significant figures (see Practice E29 for guidance). TheTABLE 1 Calcium Hydride (Percent Water)Fluid AverageRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitBiasVersusD4017KarlFischerXsr sR r R % r% R%A 68.38 1.045 3.179 2.93 8.9
46、0 4.40 4.28 13.02B 47.95 1.128 3.656 3.16 10.24 1.55 6.59 21.35C 83.93 0.779 4.317 2.18 12.09 2.41 2.60 14.40D 17.96 0.659 1.428 1.85 4.00 8.13 10.28 22.27E 2.20 0.040 0.118 0.11 0.33 14.13 5.12 15.02F 12.89 0.239 0.320 0.67 0.89 2.72 5.20 6.94Average 1.81 6.07 4.65 5.67 15.5TABLE 2 Test Method D401
47、7, Test Method for Water in Paints and Paint Materials by Karl Fischer Method (Percent Water)Fluid AverageRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitXsr sR r R r% R%A 71.53 0.931 5.656 2.61 15.84 3.64 22.14B 48.71 0.699 2.623 1.96 7.34 4.02 15
48、.08C 86.01 0.943 2.198 2.64 6.15 3.07 7.16D 19.54 0.367 1.623 1.03 4.55 5.27 23.26E 2.56 0.248 0.286 0.69 0.08 27.08 31.24F 12.55 0.338 2.345 0.95 6.56 7.55 52.33D7358 07 (2013)3report should also include the method used to determine thewater content: Test Method D7358.15. Precision and Bias715.1 Th
49、e precision of this test method is based on aninterlaboratory study of Test Method D7358, conducted in2006. Each of six laboratories tested six different materialsusing two analyses for the determination of water content; KarlFischer and a calcium hydride test. Every “test result” repre-sents an individual determination. Each laboratory obtainedtwo replicate test results (from one operator) for each material/analysis combination.15.1.1 RepeatabilityTwo test results obtained within onelaboratory shall be judged not equivalent if they differ by moreth
