{"id":48,"date":"2024-04-04T00:39:48","date_gmt":"2024-04-03T21:39:48","guid":{"rendered":"https:\/\/sisu.ut.ee\/lcms_method_validation\/61-choosing-sample-type-concentration-levels-replicates-time-range\/"},"modified":"2024-04-04T00:41:46","modified_gmt":"2024-04-03T21:41:46","slug":"61-choosing-sample-type-concentration-levels-replicates-time-range","status":"publish","type":"page","link":"https:\/\/sisu.ut.ee\/lcms_method_validation\/61-choosing-sample-type-concentration-levels-replicates-time-range\/","title":{"rendered":"6.1. Choosing sample type, concentration levels, replicates and time range for precision"},"content":{"rendered":"<p>\n\tMost guidelines agree that the used matrices should correspond as well as possible\u00a0to the matrices encountered in the routine analysis of real samples. If the precision of the whole method (not just the analytical step) <a href=\"#\" data-bs-toggle=\"modal\" data-bs-target=\"#popup-modal\" data-title=\"(1)\" data-content=\"(1) It is almost always useful to determine the precision of the whole method, not just the analytical step. So, throughout this course we generally address the precision of the whole method, unless it is explicitly stated otherwise.\">(1)<\/a>\u00a0is determined, then each replicate determination should be made from a\u00a0separate subsample and include all the steps of the method, including sample preparation.\u00a0\n<\/p>\n<ul>\n<li>\n\t\tThe sample matrices should represent samples which are routinely analyzed in the laboratory. Sample(s) can in principle be of any origin: leftovers from large routine samples, leftovers from proficiency testing samples, etc. Accurate reference values are not necessary for precision determination and it is generally not advised to use certified reference materials (CRM) as samples for determining\u00a0precision\u00a0since these are often better homogenized than real samples, leading to too optimistic estimates of the precision.\n\t<\/li>\n<li>\n\t\tA sufficient amount of sample must be available so that the required number of replicate measurements with the subsamples can be carried out.\n\t<\/li>\n<li>\n\t\tA sample should be homogeneous, so that subsamples would have as similar <span>matrix and analyte<\/span>\u00a0concentrations as possible.\n\t<\/li>\n<li>\n\t\tIn the case of determining the intermediate precision, the\u00a0sample has to be stable during a longer period of time (generally at least several months).\u00a0\u00a0\n\t<\/li>\n<\/ul>\n<h5 style=\"text-align: center\">\n\t<div class=\"ratio ratio-16x9 mb-3\"><div class=\"video-placeholder-wrapper video-placeholder-wrapper--16x9\">\n\t\t\t    <div class=\"video-placeholder d-flex justify-content-center align-items-center\">\n\t\t\t        <div class=\"overlay text-white p-2 w-100 text-center d-block justify-content-center align-items-center\">\n\t\t\t            <div>To view third-party content, please accept cookies.<\/div>\n\t\t\t            <button class=\"btn btn-secondary btn-sm mt-1 consent-change\">Change consent<\/button>\n\t\t\t        <\/div>\n\t\t\t    <\/div>\n\t\t\t<\/div>\n<\/div>Planning precision experiment\u00a0<br>\n<\/h5>\n<h5 style=\"text-align: center\">\n\t<a href=\"http:\/\/www.uttv.ee\/naita?id=23479\" target=\"_blank\" rel=\"noopener\">http:\/\/www.uttv.ee\/naita?id=23479<\/a><br>\n<\/h5>\n<h5 style=\"text-align: center\">\n\t<a href=\"https:\/\/www.youtube.com\/watch?v=L8gwuy41JD0\" target=\"_blank\" rel=\"noopener\">https:\/\/www.youtube.com\/watch?v=L8gwuy41JD0<\/a><br>\n<\/h5>\n<p>\n\t<span><span>***<\/span><\/span><br>\u00a0\n<\/p>\n<p>\n\t<span>(1) It is almost always useful to determine the precision of the whole method, not just the analytical step. So, throughout this course we generally address the precision of the whole method, unless it is explicitly stated otherwise.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Most guidelines agree that the used matrices should correspond as well as possible\u00a0to the matrices encountered in the routine analysis of real samples. If the precision of the whole method (not just the analytical step) \u00a0is determined, then each replicate &#8230;<\/p>\n","protected":false},"author":60,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"class_list":["post-48","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/pages\/48","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/users\/60"}],"replies":[{"embeddable":true,"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/comments?post=48"}],"version-history":[{"count":1,"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/pages\/48\/revisions"}],"predecessor-version":[{"id":836,"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/pages\/48\/revisions\/836"}],"wp:attachment":[{"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/media?parent=48"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}