{"term":{"id":"09907","title":"effective plate number","longtitle":"IUPAC Gold Book - effective plate number","doi":"10.1351\/goldbook.09907","code":"09907","status":"current","synonym":"<em>synonym<\/em>: number of effective plates","definitions":[{"id":1,"text":"Number indicative of column performance, calculated from the ratios of measures of adjusted retention and peak width: \\[\\eqalign{& N_{\\rm{eff}} = \\left(\\frac{V_{\\rm{R}}^{\\prime}}{\\sigma} \\right)^{2} = \\left(\\frac{t_{\\rm{R}}^{\\prime}}{\\sigma} \\right)^{2} \\cr & N_{\\rm{eff}} = 16 \\left(\\frac{V_{\\rm{R}}^{\\prime}}{w_{\\rm{b}}} \\right)^{2} = 16 \\left(\\frac{t_{\\rm{R}}^{\\prime}}{w_{\\rm{b}}} \\right)^{2} \\cr & N_{\\rm{eff}} \\approx 5.545 \\left(\\frac{V_{\\rm{R}}^{\\prime}}{w_{\\rm{h}}} \\right)^{2} \\approx 5.545 \\left(\\frac{t_{\\rm{R}}^{\\prime}}{w_{\\rm{h}}} \\right)^{2}}\\]","notes":{"1":"\\(V_{\\rm{R}}^{\\prime}\\): adjusted retention volume; \\(t_{\\rm{R}}^{\\prime}\\): total retention time; \\(\\sigma\\): standard deviation of the Gaussian peak; \\(w_{\\rm{b}}\\): peak width at base; \\(w_{\\rm{h}}\\): peak width at half height; \\(\\rm{8 \\ln 2} ≈ 5.545\\).","2":"These expressions assume a Gaussian (symmetrical) peak.","3":"Units for the quantities being divided must be consistent so that their ratio is dimensionless: i.e. if the numerator is a time, then peak width must also be expressed in terms of time","4":"The plate number is related to the effective plate number and retention factor (\\(k\\)) \\(N = N_{\\rm{eff}}{\\left(\\frac{{k + 1}}{k} \\right)^2}\\)"},"links":[{"term":"peak width at base","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/09903"},{"term":"peak width at half height","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/09904"},{"term":"total retention time","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/10039"}],"sources":["PAC, 2017, 90, 181. 'Terminology of separation methods (IUPAC Recommendations 2017)' on page 199 (https:\/\/doi.org\/10.1515\/pac-2017-0111)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/09907\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/09907\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/09907\/plain"},"citation":"Citation: 'effective plate number' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351\/goldbook.09907","license":"The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/) for individual terms.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.","accessed":"2026-07-25T10:00:59+00:00"}}