{"id":44,"date":"2024-04-04T00:39:48","date_gmt":"2024-04-03T21:39:48","guid":{"rendered":"https:\/\/sisu.ut.ee\/lcms_method_validation\/53-qualitative-estimation-matrix-effect\/"},"modified":"2024-04-04T00:41:46","modified_gmt":"2024-04-03T21:41:46","slug":"53-qualitative-estimation-matrix-effect","status":"publish","type":"page","link":"https:\/\/sisu.ut.ee\/lcms_method_validation\/53-qualitative-estimation-matrix-effect\/","title":{"rendered":"5.3 Qualitative estimation of matrix effect"},"content":{"rendered":"<p>\n\tThis and the following section will look in more detail at some of the bias components. Ionization suppression\/enhancement (matrix effect), as one of the most problematic issues in LC-MS analysis, receives the most attention, followed by recovery (and the composite of the two \u2013 process efficiency). Analyte stability, another important issue, especially in biomedical analysis, is discussed in a separate <a href=\"https:\/\/sisu.ut.ee\/lcms_method_validation\/8-stability\" target=\"_blank\" rel=\"noopener\">section 8<\/a>.\n<\/p>\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>Qualitative estimation of matrix effect<br>\n<\/h5>\n<h5 style=\"text-align: center\">\n\t<a href=\"http:\/\/www.uttv.ee\/naita?id=23477\" style=\"text-align: center;font-family: inherit;font-weight: 600\" target=\"_blank\" rel=\"noopener\">http:\/\/www.uttv.ee\/naita?id=23477<\/a><br>\n<\/h5>\n<h5 style=\"text-align: center\">\n\t<a href=\"https:\/\/www.youtube.com\/watch?v=zZNIkDy9a-Y\" target=\"_blank\" rel=\"noopener\">https:\/\/www.youtube.com\/watch?v=zZNIkDy9a-Y<\/a><br>\n<\/h5>\n<p>\n\t\u00a0\n<\/p>\n<p>\n\tThe first method of qualitative estimation of the matrix effect\u00a0is based on detecting the presence of ionization suppression <a href=\"#\" data-bs-toggle=\"modal\" data-bs-target=\"#popup-modal\" data-title=\"(1)\" data-content=\"(1) The following text is relevant for both ionization suppression and enhancement. However, since ionization suppression is significantly more common, we use only the term \u201csuppression\u201d in the following text.\">(1)<\/a>\u00a0by recording the matrix effect profile with post-column infusion [ref 25]. For this the blank sample extract \u2013 which does not contain\u00a0the analyte \u2013 is injected into the LC. At the same time, a stream of analyte solution is mixed with the chromatographic effluent exiting the column (post-column mixing)\u00a0and the mixture is delivered into the ion source. The MS monitors the analyte signal.\n<\/p>\n<p style=\"text-align: center\">\n\t<img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"864\" class=\"alignnone wp-image-409\" style=\"width: 400px;height: 346px\" src=\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/5_3_fig1_2023-1.png\" title=\"5_3_fig1_2023.png\" alt=\"5_3_Fig1_2023\" srcset=\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/5_3_fig1_2023-1.png 1000w, https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/5_3_fig1_2023-1-300x259.png 300w, https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/5_3_fig1_2023-1-768x664.png 768w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\">\n<\/p>\n<h4 style=\"text-align: center\">\n\t<strong>Figure 1. The experimental setup for recording the matrix effect profile.<\/strong><br>\n<\/h4>\n<p>\n\tThe same is done while injecting a blank solvent into the LC column. If no suppression is present, then the analyte MS signal intensities are equal for the\u00a0sample and solvent injection within the\u00a0precision\u00a0of the MS signal. For the retention time region where the ionization suppression occurs, the MS signal in the sample injection decreases. In order to have a method not affected by an ionization suppression, the analyte peak should elute away from the suppression region.\u00a0This approach does not enable quantitative evaluation of the\u00a0ionization suppression\/enhancement but only enables\u00a0confirmation of its presence\/absence and this is very useful for tuning the\u00a0chromatographic separation of the analyte and possible compounds causing ionization suppression.\n<\/p>\n<p>\n\tThe most recent FDA validation guideline proposes an evaluation of ionization suppression by assessing the parallelism of dilution plots [ref 8].\n<\/p>\n<p>\n\tWe suggest building these plots using axes \u201ccalculated analyte concentration\u201d vs \u201cdilution factor\u201d (defined as <em>V<\/em><sub>sample<\/sub>\/<em>V<\/em><sub>sum<\/sub>).\n<\/p>\n<p style=\"text-align: center\">\n\t<strong><img loading=\"lazy\" decoding=\"async\" width=\"280\" height=\"278\" class=\"alignnone wp-image-406\" src=\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/image002-4.png\" title=\"image002.png\" alt=\"image002.png\" srcset=\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/image002-4.png 280w, https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/image002-4-150x150.png 150w\" sizes=\"auto, (max-width: 280px) 100vw, 280px\"><\/strong>\n<\/p>\n<h4 style=\"text-align: center\">\n\t<strong>Figure 2. Example dilution plot of Aldicarb determination in garlic.<\/strong><br>\n<\/h4>\n<p>\n\tFrom these plots, matrix effect occurrence can be observed as a decrease (enhancements) or an increase (suppression) of the calculated concentration with a decreasing dilution factor. For example, on a plot given above, Aldicarb is experiencing strong ionization suppression, that decreases\u00a0with dilution.\u00a0\n<\/p>\n<p>\n\tThis approach is also applicable if blank matrices are not available, although no quantitative conclusions can be made based on the comparison of dilution curves.\n<\/p>\n<p>\n\t\u00a0\n<\/p>\n<div>\n\t***\n<div>\n<p>\n\t\t\t(1) The following text is relevant for both ionization suppression and enhancement. However, since ionization suppression is significantly more common, we \u00a0occasionally\u00a0use only the term \u201csuppression\u201d in the following text.\n\t\t<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>This and the following section will look in more detail at some of the bias components. Ionization suppression\/enhancement (matrix effect), as one of the most problematic issues in LC-MS analysis, receives the most attention, followed by recovery (and the composite &#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-44","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/pages\/44","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=44"}],"version-history":[{"count":1,"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/pages\/44\/revisions"}],"predecessor-version":[{"id":840,"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/pages\/44\/revisions\/840"}],"wp:attachment":[{"href":"https:\/\/sisu.ut.ee\/lcms_method_validation\/wp-json\/wp\/v2\/media?parent=44"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}