{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T17:45:17Z","timestamp":1792691117252,"version":"4.5.0"},"reference-count":24,"publisher":"Wiley","issue":"19","license":[{"start":{"date-parts":[[2012,8,28]],"date-time":"2012-08-28T00:00:00Z","timestamp":1346112000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Rapid Comm Mass Spectrometry"],"published-print":{"date-parts":[[2012,10,15]]},"abstract":"<jats:sec>\n                    <jats:title>RATIONALE<\/jats:title>\n                    <jats:p>\n                      Stable nitrogen isotope (\u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N) values of bone collagen are routinely used to inform interpretations of diet and trophic positions within contemporary and ancient ecosystems, yet the underlying physiological and biochemical factors which contribute to the bulk collagen \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N value remain little understood. Determination of individual amino acid (AA) \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N values in animal and plant proteins can help to elucidate the cycling of nitrogen and inform predictions of palaeodiet and ecology.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>METHODS<\/jats:title>\n                    <jats:p>\n                      In this study we present a methodology for the measurement of amino acid \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N values using gas chromatography\u2010combustion\u2010isotope ratio mass spectrometry (GC\u2010C\u2010IRMS). Amino acid standards of known \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N values were derivatised to their\n                      <jats:italic>N<\/jats:italic>\n                      \u2010acetylisopropyl (NAIP) esters and purified through Dowex ion\u2010exchange resin to determine any isotopic fractionation associated with derivatisation and ion\u2010exchange chromatography. The effect of starch on AA \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N values was also determined by hydrolysing bone collagen with and without the presence of starch.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>RESULTS<\/jats:title>\n                    <jats:p>\n                      The amino acids derivatised to their NAIP esters give values within \u00b10.8\u2030 of their \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N values measured separately by elemental analyser (EA)\u2010IRMS, with a precision of better than 0.8\u2030. The \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N values of AAs after Dowex ion\u2010exchange chromatography were within \u00b10.9\u2030 of their values prior to ion\u2010exchange chromatography. The AA \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N values of bone collagen hydrolysed with and without starch were within \u00b10.8\u2030.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>CONCLUSIONS<\/jats:title>\n                    <jats:p>\n                      Hydrolysis of lipid\u2010extracted plant material followed by purification of AAs using Dowex ion\u2010exchange resin and derivatisation to their NAIP esters is a suitable protocol for the accurate determination of individual plant and animal AA \u03b4\n                      <jats:sup>15<\/jats:sup>\n                      N values by GC\u2010C\u2010IRMS. Copyright \u00a9 2012 John Wiley &amp; Sons, Ltd.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/rcm.6322","type":"journal-article","created":{"date-parts":[[2012,8,31]],"date-time":"2012-08-31T20:12:55Z","timestamp":1346443975000},"page":"2328-2334","source":"Crossref","is-referenced-by-count":57,"title":["Practical considerations in the determination of compound\u2010specific amino acid \u03b4\n                    <sup>15<\/sup>\n                    N values in animal and plant tissues by gas chromatography\u2010combustion\u2010isotope ratio mass spectrometry, following derivatisation to their\n                    <i>N<\/i>\n                    \u2010acetylisopropyl esters"],"prefix":"10.1002","volume":"26","author":[{"given":"Amy K.","family":"Styring","sequence":"first","affiliation":[{"name":"Organic Geochemistry Unit, Biogeochemistry Research Centre, School of Chemistry University of Bristol  Bristol UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alison","family":"Kuhl","sequence":"additional","affiliation":[{"name":"Organic Geochemistry Unit, Biogeochemistry Research Centre, School of Chemistry University of Bristol  Bristol UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Timothy D. J.","family":"Knowles","sequence":"additional","affiliation":[{"name":"Organic Geochemistry Unit, Biogeochemistry Research Centre, School of Chemistry University of Bristol  Bristol UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rebecca A.","family":"Fraser","sequence":"additional","affiliation":[{"name":"School of Archaeology  36 Beaumont Street, University of Oxford Oxford UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amy","family":"Bogaard","sequence":"additional","affiliation":[{"name":"School of Archaeology  36 Beaumont Street, University of Oxford Oxford UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard P.","family":"Evershed","sequence":"additional","affiliation":[{"name":"Organic Geochemistry Unit, Biogeochemistry Research Centre, School of Chemistry University of Bristol  Bristol UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2012,8,28]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.6344217"},{"key":"e_1_2_6_3_1","first-page":"1138","article-title":"Stepwise enrichment of 15N along food\u2010chains \u2013 further evidence and the relation between \u03b415N and animal age","volume":"4","author":"Minagawa M.","year":"1984","journal-title":"Geochim. Cosmochim. Acta"},{"key":"e_1_2_6_4_1","doi-asserted-by":"publisher","DOI":"10.1002\/9780470691854.ch5"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1475-4754.2008.00441.x"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/0016-7037(81)90244-1"},{"key":"e_1_2_6_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/0016-7037(84)90091-7"},{"key":"e_1_2_6_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0305-4403(03)00026-8"},{"key":"e_1_2_6_9_1","doi-asserted-by":"publisher","DOI":"10.1002\/oa.662"},{"key":"e_1_2_6_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jas.2006.10.015"},{"key":"e_1_2_6_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/0305-4403(91)90066-X"},{"key":"e_1_2_6_12_1","doi-asserted-by":"publisher","DOI":"10.1006\/abio.1997.2037"},{"key":"e_1_2_6_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.gca.2009.09.022"},{"key":"e_1_2_6_14_1","doi-asserted-by":"publisher","DOI":"10.1002\/ajpa.21287"},{"key":"e_1_2_6_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jas.2006.04.009"},{"key":"e_1_2_6_16_1","first-page":"39","volume-title":"Biogeochemical Approaches to Paleodietary Analysis","author":"Klinken G. J.","year":"2000"},{"key":"e_1_2_6_17_1","doi-asserted-by":"publisher","DOI":"10.1002\/jpln.200290000"},{"key":"e_1_2_6_18_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0038-0717(99)00094-2"},{"key":"e_1_2_6_19_1","doi-asserted-by":"publisher","DOI":"10.1186\/1467-4866-4-38"},{"key":"e_1_2_6_20_1","doi-asserted-by":"publisher","DOI":"10.1080\/10256019508036284"},{"key":"e_1_2_6_21_1","doi-asserted-by":"publisher","DOI":"10.1080\/00380768.1999.10415840"},{"key":"e_1_2_6_22_1","doi-asserted-by":"publisher","DOI":"10.1042\/bj0610589"},{"key":"e_1_2_6_23_1","doi-asserted-by":"publisher","DOI":"10.1002\/rcm.3252"},{"key":"e_1_2_6_24_1","doi-asserted-by":"publisher","DOI":"10.1002\/rcm.4651"},{"key":"e_1_2_6_25_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jas.2003.12.001"}],"container-title":["Rapid Communications in Mass Spectrometry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Frcm.6322","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/analyticalsciencejournals.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/rcm.6322","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,26]],"date-time":"2025-10-26T15:10:36Z","timestamp":1761491436000},"score":1,"resource":{"primary":{"URL":"https:\/\/analyticalsciencejournals.onlinelibrary.wiley.com\/doi\/10.1002\/rcm.6322"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2012,8,28]]},"references-count":24,"journal-issue":{"issue":"19","published-print":{"date-parts":[[2012,10,15]]}},"alternative-id":["10.1002\/rcm.6322"],"URL":"https:\/\/doi.org\/10.1002\/rcm.6322","archive":["Portico"],"relation":{},"ISSN":["0951-4198","1097-0231"],"issn-type":[{"value":"0951-4198","type":"print"},{"value":"1097-0231","type":"electronic"}],"subject":[],"published":{"date-parts":[[2012,8,28]]}}}