{"id":24165,"date":"2024-07-22T09:47:44","date_gmt":"2024-07-22T07:47:44","guid":{"rendered":"https:\/\/www.linseis.com\/how-to-correctly-calibrate-a-differential-scanning-calorimeter\/"},"modified":"2024-09-13T15:19:00","modified_gmt":"2024-09-13T13:19:00","slug":"how-to-correctly-calibrate-a-differential-scanning-calorimeter","status":"publish","type":"post","link":"https:\/\/www.linseis.com\/en\/wiki\/how-to-correctly-calibrate-a-differential-scanning-calorimeter\/","title":{"rendered":"How to correctly calibrate a Differential Scanning Calorimeter"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"24165\" class=\"elementor elementor-24165 elementor-14873\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-9eb8745 e-flex e-con-boxed e-con e-parent\" data-id=\"9eb8745\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-e43865e elementor-toc--minimized-on-tablet elementor-widget elementor-widget-table-of-contents\" data-id=\"e43865e\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;headings_by_tags&quot;:[&quot;h2&quot;],&quot;exclude_headings_by_selector&quot;:[],&quot;marker_view&quot;:&quot;numbers&quot;,&quot;no_headings_message&quot;:&quot;No headings were found on this page.&quot;,&quot;minimize_box&quot;:&quot;yes&quot;,&quot;minimized_on&quot;:&quot;tablet&quot;,&quot;hierarchical_view&quot;:&quot;yes&quot;,&quot;min_height&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;min_height_tablet&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;min_height_mobile&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]}}\" data-widget_type=\"table-of-contents.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"elementor-toc__header\">\n\t\t\t\t\t\t<h4 class=\"elementor-toc__header-title\">\n\t\t\t\tTable of Contents\t\t\t<\/h4>\n\t\t\t\t\t\t\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--expand\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__e43865e\" aria-expanded=\"true\" aria-label=\"Open table of contents\"><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/div>\n\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--collapse\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__e43865e\" aria-expanded=\"true\" aria-label=\"Close table of contents\"><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<div id=\"elementor-toc__e43865e\" class=\"elementor-toc__body\">\n\t\t\t<div class=\"elementor-toc__spinner-container\">\n\t\t\t\t<svg class=\"elementor-toc__spinner eicon-animation-spin e-font-icon-svg e-eicon-loading\" aria-hidden=\"true\" viewBox=\"0 0 1000 1000\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M500 975V858C696 858 858 696 858 500S696 142 500 142 142 304 142 500H25C25 237 238 25 500 25S975 237 975 500 763 975 500 975Z\"><\/path><\/svg>\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8a9139e elementor-widget elementor-widget-heading\" data-id=\"8a9139e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Why are calibrations of thermal analyzers necessary?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-ffaef65 elementor-widget elementor-widget-text-editor\" data-id=\"ffaef65\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Why should I calibrate a meter correctly? Thermal analytical measurements like <a href=\"https:\/\/www.linseis.com\/en\/instruments\/differential-scanning-calorimeter-dsc\/\"><strong>DSCs<\/strong><\/a> are often used in quality assurance, so the measurement results must be precise and reproducible. This means the measured temperatures must be correct. Precise calibration and adjustment of the analysis equipment is therefore important.<\/p><p>Calibration determines the deviation of a reference substance from the published data. If the deviation is not within the desired tolerance range, the device must be adjusted.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e02677a elementor-widget elementor-widget-heading\" data-id=\"e02677a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h4 class=\"elementor-heading-title elementor-size-default\">A new calibration is required:<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0549d3d elementor-widget elementor-widget-text-editor\" data-id=\"0549d3d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<ul>\n<li>with new devices<\/li>\n<li>according to specified time intervals<\/li>\n<li>if the device was exposed to external interference (e.g. vibrations)<\/li>\n<li>or when routine measurements yield dubious results<\/li>\n<\/ul>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9d22ff7 elementor-widget elementor-widget-heading\" data-id=\"9d22ff7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Calibrating a DSC<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8d0f3d4 elementor-widget elementor-widget-text-editor\" data-id=\"8d0f3d4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>As a rule, phase transitions of reference substances with known transition temperatures and transition enthalpies are used to calibrate and adjust DSC measuring cells.<\/p><p>Deviations can occur in the temperature, heating rate, and heat flow parameters on the sensor, so these need to be calibrated; see also <a href=\"https:\/\/www.astm.org\/e0967-18.html\" data-wplink-edit=\"true\" target=\"_blank\" rel=\"noopener\"><strong>ASTM E 967-97<\/strong><\/a> and <a href=\"https:\/\/www.astm.org\/e0968-99.html\" target=\"_blank\" rel=\"noopener\"><strong>ASTM E 968-99<\/strong><\/a>. If the deviations are within the tolerance range, the measurement of the samples can be started. If this is not the case, adjustments will need to be made.<\/p><p>The crucible material (thermal conductivity, mass, geometry, size of the holes in the lid), the furnace atmosphere, the flow rate of the purging gas, and the DSC sensor itself can influence the parameters. Due to the countless resulting combinations of measurements, a separate adjustment is required for each combination.<\/p><p><strong>The following sequence of adjustments has proven useful: first tau lag, then temperature, and finally sensor adjustment.<\/strong><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-bf6dc7b elementor-widget elementor-widget-heading\" data-id=\"bf6dc7b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h4 class=\"elementor-heading-title elementor-size-default\">1. Tau lag adjustment<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6e009f7 elementor-widget elementor-widget-text-editor\" data-id=\"6e009f7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Tau lag is a time constant that describes the behavior of the furnace. When adjusted, the dynamic behavior of the measuring cell is corrected. It also ensures that the apparent influence of the heating rate has no effect on the measurement result. If the onset temperature of indium is determined at different, increasing heating rates without dew point adjustment, the onset melting temperature shifts to higher temperatures, which is physically incorrect. At least two substances with different onset temperatures within the temperature range of interest are useful for an adjustment.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-29dcc77 elementor-widget elementor-widget-heading\" data-id=\"29dcc77\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h4 class=\"elementor-heading-title elementor-size-default\">2. Temperature adjustment<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7e0fa8d elementor-widget elementor-widget-text-editor\" data-id=\"7e0fa8d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Temperature adjustment ensures that the onset temperatures correspond exactly to the published values. An adjustment with at least two substances with different onset temperatures is also recommended here.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0b48f91 elementor-widget elementor-widget-heading\" data-id=\"0b48f91\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h4 class=\"elementor-heading-title elementor-size-default\">3. Sensor adjustment<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-89253ae elementor-widget elementor-widget-text-editor\" data-id=\"89253ae\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>The sensor adjustment is used to correct the signal value of the heat flow from sensor to crucible and crucible to sample. Here, too, we recommend adjusting with at least two references to obtain a high level of accuracy within the temperature range of interest.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-77058db elementor-widget elementor-widget-spacer\" data-id=\"77058db\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8316d48 elementor-widget elementor-widget-spacer\" data-id=\"8316d48\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f8f562d elementor-widget elementor-widget-text-editor\" data-id=\"f8f562d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>A measurement process therefore requires the following steps: calibration, adjustment, checking the adjustment through repeated calibration, and only then sample measurement.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6608aa2 elementor-widget elementor-widget-heading\" data-id=\"6608aa2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Certified reference substances for calibration<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e20a524 elementor-widget elementor-widget-text-editor\" data-id=\"e20a524\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><strong>Reference substances should be easy to use, easily accessible, and stable.<\/strong><\/p><p>Their melting point or enthalpy of fusion should be within the measurement range of interest, since extrapolations lead to inaccurate results.<\/p><p>Pure metals (&gt;99.99% purity) such as gallium, indium, and tin, but also organic substances such as adamantane, benzoic acid, and naphthalene are used as calibration references.<\/p><p>Certified reference substances for temperature and heat calibration of DSCs are offered by <a href=\"https:\/\/www.lgcstandards.com\/GB\/en\/\" target=\"_blank\" rel=\"noopener\"><strong>LGC (UK)<\/strong><\/a>, <a href=\"https:\/\/www.nist.gov\/\" target=\"_blank\" rel=\"noopener\"><strong>NIST (USA)<\/strong><\/a> and <a href=\"https:\/\/ptb.de\/cms\/en.html\" target=\"_blank\" rel=\"noopener\"><strong>PTB (Germany)<\/strong><\/a>. These are traceable reference materials. Such substances meet all the requirements of relevant quality management standards such as ISO 9000 and DIN EN ISO\/IEC 17025.<\/p><p>In addition, some liquid crystals are available as certified secondary reference substances for the cooling mode. For purity determinations of slightly contaminated substances, LGC also offers reference substances with certified impurities.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d6f70b7 elementor-widget elementor-widget-spacer\" data-id=\"d6f70b7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Correct calibration of a DSC &#8211; Why is correct calibration so important? Thermoanalytical measurements are often used in quality assurance; <\/p>\n","protected":false},"author":3,"featured_media":14876,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[106],"tags":[],"class_list":["post-24165","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-wiki"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/posts\/24165","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/comments?post=24165"}],"version-history":[{"count":0,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/posts\/24165\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/media\/14876"}],"wp:attachment":[{"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/media?parent=24165"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/categories?post=24165"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/tags?post=24165"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}