ASTM E1148-2002 Standard Test Method for Measurements of Aqueous Solubility《水溶解度测量用标准试验方法》.pdf
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1、Designation: E 1148 02Standard Test Method forMeasurements of Aqueous Solubility1This standard is issued under the fixed designation E 1148; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in par
2、entheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers procedures for measurement ofthe solubility of organic compounds in water. Three proceduresare described which will work ov
3、er a variety of solubilityranges. These procedures are not appropriate for compoundsthat react with water or air at ambient conditions.1.2 The procedure chosen will depend on the estimatedsolubility of the compound. This may be obtained fromliterature values (see Refs 1, 2, 3)2by correlation with ot
4、herparameters (4) or by analogy with the solubility of similarcompounds.1.3 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine t
5、he applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D 1193 Specification for Reagent Water3. Terminology Definition3.1 solubility in waterthe extent to which a substancemixes with pure water to form a molecular homogeneoussystem at a given temperature.
6、 For the case of a single puresubstance, solubility in water is an equilibrium state (5). Theparticular method used will define what one means by aqueoussolubility.4. Significance and Use4.1 The solubility of organics is a basic physical parameterneeded for the prediction of the fate of a chemical i
7、n theenvironment (6).4.1.1 The ionic strength and organic content of naturalwaters may cause an apparent decrease or increase from thevalue obtained in pure water. Data on this can be obtained inthe laboratory by modifying the reagent water to simulatenatural waters.5. Reagents5.1 Reagent grade or b
8、etter chemicals shall be used in allprocedures. It is intended that all reagents shall conform to thespecifications of the Committee on Analytical Reagents of theAmerican Chemical Society,4where such specifications areavailable. Lower grades may be used provided it is firstascertained that the impur
9、ities do not interfere with theprocedure.5.2 Purity of WaterReagent water shall conform to Speci-fication D 1193 for Type II grade water.6. Sampling6.1 Take at least 3 samples at appropriate intervals andanalyze to demonstrate that equilibrium has been reached.Equilibrium is defined as identical con
10、centrations within theprecision of the analytical method.7. Procedure7.1 Determine solubilities at 25C5and any other tempera-ture as appropriate. Measure those chemicals that reversiblyionize or protonate at a pH of pKa + 2 pH units and a pH ofpKa 2 pH units for pKa values which fall in the range of
11、 5 to9 (7) , as well as nonionizable organics.Adjust the system withHCl or NaOH as appropriate. A weak buffer (for example,0.001 M) may be useful to stabilize the pH, depending on thesolubility of the test substance. Report the solubility as mg/L atthe experimental temperature and pH. For lower solu
12、bilities itis suggested, in order to minimize losses due to adsorption, thatall transfer apparatus should be prerinsed with portions of thesolution.1This test method is under the jurisdiction of ASTM Committee E47 onBiological Effects and Environmental Fate and is the direct responsibility ofSubcomm
13、ittee E47.04 on Environmental Fate of Chemical Substances.Current edition approved January 10, 2002. Published March 2002. Originallypublished as E114887. Last previous edition E114887(1993)e1.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.3For ref
14、erenced 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.4“Reagent Chemicals,American Chemical Society Specifications,”Am. Che
15、mi-cal Soc., Washington, DC. For suggestions on the testing of reagents not listed bytheAmerican Chemical Society, see “Reagent Chemicals and Standards,” by JosephRosin, D. Van Nostrand Co., Inc., New York, NY, and the “United StatesPharmacopeia.”5International Union of Pure andApplied Chemistry (IU
16、PAC),“ Commission onThermodynamics and Thermochemistry,”AGuide to Procedures for the Publicationof Thermodynamic Data, Pure and Applied Chemistry, Vol 29, No. 397, 1972.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.1.1 The effect
17、 of ionic strength or organic matter or bothmay be studied by adding appropriate substances in the reagentwater.7.2 Method A1Solubilities of 1 mg/L or Greater:7.2.1 Obtain equilibrium by gently shaking or stirring ap-propriately an excess of the compound in a flask of reagentwater. Equilibrium times
18、 will depend upon the physical prop-erties of the compound. Obtain the solubility by periodicallydetermining the concentration of the solute over a length oftime, at least 2 h between determinations. The solute concen-tration will assume a constant value, within experimental error,as equilibrium is
19、attained. Before analysis, centrifuge thesolution at the test temperature to ensure the removal of anysuspended solute. Use a constant temperature centrifuge andrun at about 12 000 g for at least 20 min6(8). Take care tomaintain a constant temperature throughout the procedure.t 5 9/2 h/v2rp2rp2rwln
20、Rb/Rt(1)where:v2= 4 p2r/min!23600t = time in seconds,r/min = revolutions per minute,Rt= distance in centimetres from center of centrifugerotor to top of solution in centrifuge tube, andRb= distance in centimetres from center of centrifugerotor to bottom of centrifuge tube.Taking the following values
21、 as typical:rp= particle radius = 0.1 mh = viscosity of water = 0.8904 3 102g/s cm at 25C,rp= particle density = 1.20 g/cm3(for this example),rw= density of water = 0.997 g/cm3at 25C, andt = 1.83 3 1011r/min!2ln Rb/Rt.In general practice, double the calculated centrifuge times toassure complete sepa
22、ration.7.2.2 This technique is suitable only if particles may beremoved by centrifugation. Filtration may be used if it isdemonstrated that no soluble material is lost by adsorption andthat filtration removes insoluble material (9) . Liquid-liquidseparations may be used if the particles can be extra
23、ctedselectively. If a stable suspension is formed, use 7.37.3 Method A2Solubilities of 1 mg/L or Greater:7.3.1 The nephelometric technique involves making severalserial dilutions of a stable suspension of known concentrations.Alternatively, suspensions of various concentrations can beproduced by mix
24、ing (10 s sonication is often effective) aliquotsof a water miscible solvent solution of the test substance.Aplotof total concentration versus turbidity (measured with any of avariety of turbidimeters) should yield a straight line (10, 11,12). Use standard techniques of linear regression to estimate
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