National Institute of Standards and Technology

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNational Institute of Standards and TechnologyCite this: Anal. Chem. 1990, 62, 11, 661APublication Date (Print):June 1, 1990Publication History Published online6 June 2012Published inissue 1 June 1990https://doi.org/10.1021/ac00210a736RIGHTS & PERMISSIONSArticle Views11Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (688 KB) Get e-Alerts Get e-Alerts