{"id":71655,"date":"2025-12-05T17:22:38","date_gmt":"2025-12-05T17:22:38","guid":{"rendered":"https:\/\/discover.restek.com\/?p=71655"},"modified":"2026-04-08T19:18:19","modified_gmt":"2026-04-08T19:18:19","slug":"how-does-restek-determine-the-isomeric-ratio-of-pfas-standards","status":"publish","type":"post","link":"https:\/\/discover.restek.com\/ja\/faq-zh\/gnot5431\/how-does-restek-determine-the-isomeric-ratio-of-pfas-standards","title":{"rendered":"How does Restek determine the isomeric ratio of PFAS standards?"},"content":{"rendered":"\n<p>The ratio and linear and the sum of branched isomers is determined chromatographically by the method outlined in the certificate of analysis (CofA). Results are summarized for each compound in the component table.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"248\" src=\"https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-01-1024x248.jpg\" alt=\"\" class=\"wp-image-74676\" title=\"-\" srcset=\"https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-01-1024x248.jpg 1024w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-01-300x73.jpg 300w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-01-768x186.jpg 768w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-01-1536x373.jpg 1536w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-01.jpg 1814w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"has-text-align-center\"><em>Excerpt from br-PFHxS standard (<\/em><a href=\"https:\/\/www.restek.com\/p\/30803\" target=\"_blank\" rel=\"noopener\">cat. # 30803<\/a><em>) certificate of analysis.<\/em><\/p>\n\n\n\n<p>Isomers are further identified by <sup>19<\/sup>FNMR and can be found in the standard\u2019s data packet.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"2272\" height=\"717\" src=\"https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-02.jpg\" alt=\"\" class=\"wp-image-74682\" title=\"-\" srcset=\"https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-02.jpg 2272w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-02-300x95.jpg 300w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-02-1024x323.jpg 1024w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-02-768x242.jpg 768w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-02-1536x485.jpg 1536w, https:\/\/discover.restek.com\/wp-content\/uploads\/figure-article-GNOT5431-02-2048x646.jpg 2048w\" sizes=\"auto, (max-width: 2272px) 100vw, 2272px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"has-text-align-center\"><em>Excerpt from br-PFHxS standard (<\/em><a href=\"https:\/\/www.restek.com\/p\/30803\" target=\"_blank\" rel=\"noopener\">cat. # 30803<\/a><em>) data packet.<\/em><\/p>\n\n\n\n<div class=\"wp-block-group hub-fullwidth-container\"><div class=\"wp-block-group__inner-container is-layout-constrained wp-block-group-is-layout-constrained\"><style>.kadence-column71655_85a964-9a > .kt-inside-inner-col,.kadence-column71655_85a964-9a > .kt-inside-inner-col:before{border-top-left-radius:16px;border-top-right-radius:16px;border-bottom-right-radius:16px;border-bottom-left-radius:16px;}.kadence-column71655_85a964-9a > .kt-inside-inner-col{column-gap:var(--global-kb-gap-sm, 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.wp-block-kadence-advancedgallery{align-self:stretch;}.kadence-column71655_cd2bb5-14 > .kt-inside-inner-col > .aligncenter{width:100%;}.kt-row-column-wrap > .kadence-column71655_cd2bb5-14{align-self:center;}.kt-inner-column-height-full:not(.kt-has-1-columns) > .wp-block-kadence-column.kadence-column71655_cd2bb5-14{align-self:auto;}.kt-inner-column-height-full:not(.kt-has-1-columns) > .wp-block-kadence-column.kadence-column71655_cd2bb5-14 > .kt-inside-inner-col{flex-direction:column;justify-content:center;}.kadence-column71655_cd2bb5-14 > .kt-inside-inner-col:before{opacity:0.3;}.kadence-column71655_cd2bb5-14{position:relative;}.kadence-column71655_cd2bb5-14, .kt-inside-inner-col > .kadence-column71655_cd2bb5-14:not(.specificity){margin-top:var(--global-kb-spacing-xs, 1rem);margin-bottom:var(--global-kb-spacing-xs, 1rem);}@media all and (max-width: 1024px){.kt-row-column-wrap > .kadence-column71655_cd2bb5-14{align-self:center;}}@media all and (max-width: 1024px){.kt-inner-column-height-full:not(.kt-has-1-columns) > .wp-block-kadence-column.kadence-column71655_cd2bb5-14{align-self:auto;}}@media all and (max-width: 1024px){.kt-inner-column-height-full:not(.kt-has-1-columns) > .wp-block-kadence-column.kadence-column71655_cd2bb5-14 > .kt-inside-inner-col{flex-direction:column;justify-content:center;}}@media all and (max-width: 1024px){.kadence-column71655_cd2bb5-14 > .kt-inside-inner-col{flex-direction:column;justify-content:center;align-items:flex-start;}}@media all and (max-width: 767px){.kt-row-column-wrap > .kadence-column71655_cd2bb5-14{align-self:center;}.kt-inner-column-height-full:not(.kt-has-1-columns) > .wp-block-kadence-column.kadence-column71655_cd2bb5-14{align-self:auto;}.kt-inner-column-height-full:not(.kt-has-1-columns) > .wp-block-kadence-column.kadence-column71655_cd2bb5-14 > .kt-inside-inner-col{flex-direction:column;justify-content:center;}.kadence-column71655_cd2bb5-14 > .kt-inside-inner-col{flex-direction:column;justify-content:center;align-items:flex-start;}}<\/style>\n<div class=\"wp-block-kadence-column kadence-column71655_cd2bb5-14 kb-section-dir-vertical\"><div class=\"kt-inside-inner-col\"><style>.wp-block-kadence-advancedheading.kt-adv-heading71655_66c36c-15, .wp-block-kadence-advancedheading.kt-adv-heading71655_66c36c-15[data-kb-block=\"kb-adv-heading71655_66c36c-15\"]{padding-right:0px;padding-left:0px;text-align:left;font-size:40px;font-weight:400;font-style:normal;font-family:Inter;text-transform:none;}.wp-block-kadence-advancedheading.kt-adv-heading71655_66c36c-15 mark.kt-highlight, .wp-block-kadence-advancedheading.kt-adv-heading71655_66c36c-15[data-kb-block=\"kb-adv-heading71655_66c36c-15\"] mark.kt-highlight{font-style:normal;color:#f76a0c;-webkit-box-decoration-break:clone;box-decoration-break:clone;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;}.wp-block-kadence-advancedheading.kt-adv-heading71655_66c36c-15 img.kb-inline-image, .wp-block-kadence-advancedheading.kt-adv-heading71655_66c36c-15[data-kb-block=\"kb-adv-heading71655_66c36c-15\"] img.kb-inline-image{width:150px;vertical-align:baseline;}@media all and (max-width: 767px){.wp-block-kadence-advancedheading.kt-adv-heading71655_66c36c-15, .wp-block-kadence-advancedheading.kt-adv-heading71655_66c36c-15[data-kb-block=\"kb-adv-heading71655_66c36c-15\"]{font-size:36px;}}<\/style>\n<h2 class=\"kt-adv-heading71655_66c36c-15 wp-block-kadence-advancedheading has-theme-palette-9-color has-text-color\" data-kb-block=\"kb-adv-heading71655_66c36c-15\"><strong>Find Reference Standards Fast<\/strong><\/h2>\n\n\n<style>.wp-block-kadence-advancedheading.kt-adv-heading71655_731bc7-26, 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class=\"kt-btn-inner-text\">START YOUR SEARCH<\/span><span class=\"kb-svg-icon-wrap kb-svg-icon-fe_arrowRight kt-btn-icon-side-right\"><svg viewBox=\"0 0 24 24\"  fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"  aria-hidden=\"true\"><line x1=\"5\" y1=\"12\" x2=\"19\" y2=\"12\"\/><polyline points=\"12 5 19 12 12 19\"\/><\/svg><\/span><\/a><\/div>\n<\/div><\/div>\n<\/div><\/div>\n\n\n\n<p class=\"has-text-align-center\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The ratio and linear and the sum of branched isomers is determined chromatographically by the method outlined in the certificate of analysis (CofA). Results are summarized for each compound in the component table. Excerpt from br-PFHxS standard (cat. # 30803) certificate of analysis. 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