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
25、the concentration at zero turbidity or the turbidity of solventcontrols, the value of which represents solubility. The sensi-tivity of the procedure to mixing time, equilibration time, andother aspects will vary with the equipment used and should bedocumented in each laboratory. This procedure is no
26、t chemicalspecific and it can be valuable for mixtures or difficultanalyses. Errors may be introduced by a cosolvent, incompletesuspension of the test substance, or a less soluble impurity.7.4 Method BSolubilities less than 1 mg/L:7.4.1 The basic problem presented by solubility measure-ments of thes
27、e compounds is the time required to reachequilibrium and adsorption of compounds on the surfaces ofequipment. At very low concentrations, less than 1 g/L, thedefinition of water solubility may become ill-defined becauseof the presence of dimers and molecular clusters. The generatorcolumn method of M
28、ay, Wasik, and Freeman is preferable forcompounds of low-water solubility in many cases (13). Aseparate ASTM test method using a generator column is underdevelopment. The U.S. EPA has also published this method inthe Toxic Substances Control Act Test Guidelines (5). Thefollowing procedure is a modif
29、ication of the method of Haqueand Schmedding (14).7.4.2 Dissolve a sample of the compound in an appropriatevolatile solvent. Swirl this onto the walls of a well-cleanedglass carboy. Insure that excess compound is present. Do notallow the mixture to reach the bottom of the carboy. Residualsolvent is
30、evaporated using a nitrogen stream leaving a thinfilm of the compound on the carboy walls. Reagent water isslowly added along with a magnetic stirring bar and the carboysealed airtight. Isolate each carboy from the magnetic stirrer bya12-in. thick sheet of insulating material to minimize tempera-tur
31、e gradients.7.4.3 Stir solutions at about 250 r/min and take samplesperiodically through the air tight seal (at least once per week)until equilibrium is reached. In order to minimize losses due toadsorption, design the experiment to minimize transfers andprerinse all transfer apparatus with portions
32、 of the solution.Stop stirring for 24 h before taking samples. Take and analyzesamples as appropriate. After the equilibrium point is reached,cease stirring and continue sampling until a new equilibrium,representing solubility, is reached. Centrifuge all samples toremove excess undissolved compound
33、before analysis (see7.2.1 for details).8. Report8.1 Include in the report the following information:8.1.1 Procedure used and any modifications, the specificanalytical technique used, pH, and temperature.8.1.2 Time to reach equilibrium if applicable. This may bedone by plotting solubility versus time
34、.8.1.3 If Method A 2 is used, include the concentrationversus turbidity plot.8.1.4 Report values as mean plus or minus one standarddeviation and the number of measurements used to calculatethe mean.9. Precision and Bias9.1 Precision and bias will depend upon the specific methodchosen for the determi
35、nation, upon the method used fordetection and analysis, and upon the solubility of the material6Centrifuge time to remove particles from suspension can be calculatedassuming spherical particles.E1148022itself. No interlaboratory test for the evaluation of precisionand bias has been conducted at this
36、 time.10. Keywords10.1 aqueous solubility; solubility of organic compounds inwaterREFERENCES(1) Gunther, F. A., Westlake, W. E., and Jaglan, W. E.,“ ReportedSolubilities of 728 Pesticide Chemicals in Water,” Residue Reviews,Vol 20, 1968, p. 1.(2) Seidell, A., Solubility of Inorganic, Metalorganics a
37、nd Organic Com-pounds, 3rd ed., D. Van Nostrand Co., New York, 1940.(3) Stephen, J., and Stephen, T., Solubility of Inorganic and OrganicCompounds, Vol 1, Binary Systems, Part 1, The Macmillan Co., NewYork. 1963.(4) Kenaga, E. E., and Goring, C. A. I., “Relationship Between WaterSolubility, Soil-Sor
38、ption, Octanol-Water Partitioning and Bioconcen-tration of Chemicals in Biota,” in ASTM 3rd Aquatic ToxicologySymposium, Oct. 1718, 1978, ASTM STP 707, 1980.(5) U. S. Environmental Protection Agency, “Chemical Fate TestingGuidelines, Subpart B-Physical and Chemical Properties, Section796.1840 Water
39、Solubility (Generator Column Method),” FederalRegister, Vol 50, No. 188, 1985, pp. 3926539270.(6) Metcalf, R. L., “Model Ecosystem Approach to Insecticide Degrada-tion:ACritique,” Annual Reviews of Entomology, Vol 22, 1977, p 241.(7) Cheung, M. W., and Bigger, J. W., “Solubility and Molecular Struct
40、ureof 4-amino-3,5,6-trichloropicolinic Acid in Relation to pH and Tem-perature,” Journal of Agricultural and Food Chemistry, Vol 22, No. 2,1974, pp. 202206.(8) Hoermann, W. D., and Eberle, D. O., “The Aqueous Solubility of2-chloro-4-ethylamino-6-isopropylamino-1,3,5 triazine (Atrazine) Ob-tained by
41、an Improved Analytical Method,” Weed Research, Vol 12,1972, p. 199.(9) Hashimoto,Y., et al.,“AComparison of Water Solubilities by the Flaskand Micro Column Methods,” Chemosphere, Vol 11, 1982, pp.9911001.(10) Davis, W. and Parke, T., “A Nephelometric Method for Determina-tion of Solubilities of Extr
42、emely Low Order,” Journal of theAmerican Chemical Society, Vol 64, 1942, pp. 101107.(11) Furer, R. and Geiger, M. “A Simple Method of Determining theAqueous Solubility of Organic Substances,” Pesticide Science, Vol 8,1977, p. 337.(12) Hollifield, H. C.,“ Rapid Nephelometric Estimate of Water Solubil
43、ityof Highly Insoluble Organic Chemicals of Environmental Interest,”Bulletin of Environmental Contamination and Toxicology, Vol 23,1979, p. 579.(13) May, W. E., Wasik, S. P., and Freeman, D. H.“ Determinations of theAqueous Solubility of Polynuclear Aromatic Hydrocarbons by aCoupled Column Liquid Ch
44、romatographic Technique,” AnalyticalChemistry, Vol 50, 1978, p. 175.(14) Haque, R. and Schmedding, D., “A Method of Measuring the WaterSolubility of Hydrophobic Chemicals,” Bulletin of EnvironmentalContamination and Toxicology, Vol 14, No. 1, 1975, p. 13.ASTM International takes no position respecti
45、ng 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 rights, and the riskof infringement of such rights, are entirely their own responsibility.This stand
46、ard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Internation
47、al 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 hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.T
48、his 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).E1148023
