Hostname: page-component-77c89778f8-swr86 Total loading time: 0 Render date: 2024-07-17T16:48:16.574Z Has data issue: false hasContentIssue false

Interlaboratory Comparison of Amino Acid Enantiomeric Ratios in Fossil Pleistocene Mollusks

Published online by Cambridge University Press:  20 January 2017

John F. Wehmiller*
Affiliation:
Department of Geology, University of Delaware, Newark, Delaware 19711

Abstract

Enantiomeric (d/l) ratios of eight amino acids in three homogeneous powdered fossil Pleistocene mollusk samples have been compared. Eleven laboratories have contributed results to this effort. Three gas chromatographic methods and one ion-exchange chromatographic method were used. In general, the coefficients of variation (c.v.) are best for alanine, glutamic acid, and aspartic acid (3–8%). For leucine and phenylalanine, the c.v.'s are between 5 and 10%. For isoleucine, proline, and valine the c.v.'s range from 10 to 18%. Individual laboratories usually report analytical precision of between 2 and 5%, but it is clear that significant differences between laboratories' results are often encountered, and that these analytical differences could, in some cases, lead to very significant differences (25% or more) in age estimates based upon enantiomeric ratios. Multiple analyses of desalted hydrolyzates of these powder samples suggest that interlaboratory differences are often caused by instrumental and/or derivatization procedures rather than the wet-chemical sample preparative steps. It is proposed that the powder samples described here be used in all future publications of fossil amino acid enantiomeric ratio data.

Type
Research Article
Copyright
University of Washington

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bada, J.L. Hoopes, E. Darling, D. Dungworth, G. Kessels, H.J. Kvenvolden, K.A. and Blunt, D.J. (1979). Amino acid racemization dating of fossil bones. I. Inter-laboratory comparison of racemization measurements Earth and Planetary Science Letters 43 265 268 CrossRefGoogle Scholar
Frank, H. Nicholson, G.J. Bayer, E. (1977). Rapid gas chromatographic separation of amino acid enantiomers with a novel chiral stationary phase Journal of Chromatographic Science 15 174 176 Google Scholar
Hare, P.E. (1975). Amino acid composition by column chromatography Needleman, S.B. Molecular Biology, Biochemistry, and Biophysics 8 205 231 Google Scholar
Hoopes, E.A. Peltzer, E.T. Bada, J.L. (1978). Determination of amino acid enantiomeric ratios by gas liquid chromatography of the N-trifluoroacetyl-L-prolyl-peptide methyl esters Journal of Chromatographic Science 16 556 560 Google Scholar
Kennedy, G.L. (1978). Pleistocene Paleoecology, Zoogeography, and Geochronology of Marine Invertebrate Faunas of Pacific Northwest Coast (San Francisco Bay to Puget Sound) Ph.D. dissertation Department of Geology, University of California Davis 1 824 Google Scholar
Kennedy, G.L. Lajoie, K.R. Wehmiller, J.F. (1982). Aminostratigraphy and faunal correlations of late Quaternary marine terraces, Pacific coast, U.S.A. Nature (London) 299 545 547 CrossRefGoogle Scholar
Kvenvolden, K.A. (1980). Interlaboratory comparison of amino acid racemization in a Pleistocene mollusk, Saxidomus giganteus Hare, P.E. Hoering, T.C. King, K. Jr. Biogeochemistry of Amino Acids Wiley New York 223 232 Google Scholar
Kvenvolden, K.A. Peterson, E. Pollock, G.E. (1972). Geochemistry of amino acid enantiomers: Gas chromatography of their diastereoisomeric derivatives von Gaertner, H.R. Wehner, H. Advances in Organic Geochemistry 1971 Pergamon Braunschweig 387 401 Google Scholar
McCartan, L. Owens, J.P. Blackwelder, B.W. Szabo, B.J. Belknap, D.F. Kriausakul, N. Mitterer, R.M. Wehmiller, J.F. (1982). Comparison of amino acid racemization geochronometry with lithostratigraphy, biostratigraphy, uraniumseries coral dating, and magnetostratigraphy in the Atlantic coastal plain of the southeastern United States Quaternary Research 18 337 359 Google Scholar
Pollock, G.E. Kawauchi, A.H. (1968). Resolution of racemic aspartic acid, tryptophan, hydroxy and sulfhydryl amino acids by gas chromatography Analytical Chemistry 40 1356 1358 CrossRefGoogle ScholarPubMed
Wehmiller, J.F. (1982). Interlaboratory comparison of amino acid enantiomeric ratios in fossil mollusks Geological Society of America, Abstracts with Programs 14 644 Google Scholar
Wehmiller, J.F. Emerson, W.K. (1980). Calibration of amino acid racemization in late Pleistocene mollusks: Results from Magdalena Bay, Baja California Sur, Mexico, with dating applications and paleoclimatic implications The Nautilus 94 31 36 Google Scholar
Wehmiller, J.F. Belknap, D.F. (1982). Amino acid age estimates, Quaternary Atlantic coastal plain: Comparison with U-series dates, biostratigraphy, and paleomagnetic control Quaternary Research 18 311 336 Google Scholar
Wehmiller, J.F. Lajoie, K.R. Kvenvolden, K.A. Peterson, E. Belknap, D.F. Kennedy, G.L. Addicott, W.O. Vedder, J.G. Wright, R.W. (1977). Correlation and chronology of Pacific coast marine terraces of continental United States by amino acid stereochemistry—Technique evaluation, relative ages, kinetic model ages, and geologic implications U.S. Geological Survey Open-File Report 77-680 1 196 Google Scholar