ASTM_E_1147_-_92_1997.pdf

Designation:E 1147 92(Reapproved 1997)Standard Test Method forPartition Coefficient(N-Octanol/Water)Estimation by LiquidChromatography1This standard is issued under the fixed designation E 1147;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 parentheses 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 describes a procedure for the estima-tion of the log of the octanol/water partition coefficient(logKow)of chemicals over the range from 0 to 8.1.2 This test method uses an empirically derived equation torelate the octanol/water partition coefficient to an experimen-tally determined retention time on a liquid chromatographiccolumn.1.3 This test method has been designed to estimate logKowvalues for both non-ionizable and ionizable compounds.This is accomplished by buffering the liquid chromatographicsolvent at a pH that will force the test compound into either thenon-ionized or ionized form.1.4 This test method requires some knowledge of thedetector response to the chemical being tested.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish safetyand health practices and determine the applicability of regu-latory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E 200 Practice for Preparation,Standardization,and Stor-age of Standard Solutions for Chemical Analysis3E 682 Practice for Liquid Chromatography Terms and Re-lationships4E 1022 Practice for Conducting Bioconcentration Tests withFishes and Saltwater Bivalve Molluscs53.Terminology3.1 Definitions:3.1.1 octanol/water partition coeffcient(Kow)the equilib-rium ratio of the molar concentrations of a chemical inn-octanol and water,in dilute solution.Kowis a constant for aspecific chemical at a given temperature.Since Kowis the ratioof two molar concentrations,it is a dimensionless quantity.Kowis often reported as log Kow.3.1.2 retention time(tR,to)the reference compound or testchemical retention time(tR)is the time from sample injectionto maximum concentration(peak height)of eluted referencecompound or test chemical.The internal standard retentiontime(to)is the time from sample injection to the maximumconcentration(peak height)of the eluted internal standard.4.Summary of Test Method4.1 This test method is based on the work of Veith et al(1).6Another similar test method is available from OECD(2).4.2 The test substance(solute)is injected onto a liquidchromatograph column containing a solid-phase support ontowhich a commercially available long-chain hydrocarbon(forexample C8 or C18)has been bonded.Chemicals injected ontosuch a column move along it by partitioning between themobile phase and the stationary hydrocarbon phase.Amethanol/water solvent system is typically used to elute thesolute which is subsequently analyzed using an ultraviolet/visible absorption detector,refractive index detector,electro-chemical detector,or other appropriate detector.If the testsubstance is not amenable to detection by the available LCdetectors,the analyst may collect fractions of the columneffluent and analyze for the test substance using gas chroma-tography,liquid scintillation,or other appropriate technique.4.3 The Kowof the test compound is estimated from a linearregression equation developed from a plot of log(tR to)versuslog Kow,using data determined in a calibration step thatinvolves injecting into the chromatograph a mixture of refer-ence chemicals.4.4 A calibration graph of log(tR to)versus log Kowisdeveloped for a number of reference compounds(typicallybetween 5 and 10)which are structurally similar to the testchemical.Lists of values of measured log Koware available formany chemicals(3,4,5).If data on the partition coefficients ofstructurally related compounds are not available,a moregeneral calibration graph must be developed using otherreference compounds.This is a less accurate approach than that1This test method is under the jurisdiction of ASTM Committee E-47 onBiological Effects and Environmental Fate and is the direct responsibility ofSubcommittee E47.06 on Environmental Fate of Chemical Substances.Current edition approved Aug.15,1992.Published October 1992.Originallypublished as E 1147 87.Last previous edition E 1147 87.2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 15.05.4Annual Book of ASTM Standards,Vol 14.01.5Annual Book of ASTM Standards,Vol 11.05.6The boldface numbers in parentheses refer to the list of references at the end ofthis test method.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.using partition coefficient values for related compounds.5.Significance and Use5.1 The octanol/water partition coefficient has been