{"id":76432,"date":"2022-08-24T00:00:00","date_gmt":"2022-08-24T00:00:00","guid":{"rendered":"https:\/\/discover.restek.com\/?p=76432"},"modified":"2026-01-28T17:39:07","modified_gmt":"2026-01-28T17:39:07","slug":"improved-indeno123-cdpyrene-dibenzahanthracene-separation-on-the-new-rxi-svocms-column","status":"publish","type":"post","link":"https:\/\/discover.restek.com\/ja\/blogs\/gnbl5506\/improved-indeno123-cdpyrene-dibenzahanthracene-separation-on-the-new-rxi-svocms-column","title":{"rendered":"Improved Indeno[123-cd]pyrene-Dibenz[ah]anthracene Separation on the New Rxi-SVOCms Column"},"content":{"rendered":"\n<p>When we started development of the Rxi-SVOCms column, we focused on maximizing the resolution of PAH isobars while targeting a 16-minute elution time for benzo[ghi]perylene (<strong>BghiP<\/strong>) on a 30 m x 0.25 mm x 0.25 \u00b5m column using our optimized split injection SVOA acquisition parameters [GC_EV1604]. The benzo[b]fluoranthene &#8211; benzo[k]fluoranthene (<strong>BbF<\/strong>&nbsp;&#8211;&nbsp;<strong>BkF<\/strong>) separation draws the most attention, but we also put significant resources into maximizing the indeno[123-cd]pyrene \u2013 dibenz[ah]anthracene (<strong>IcdP<\/strong>&nbsp;&#8211;&nbsp;<strong>DahA<\/strong>) separation in the allotted time.<\/p>\n\n\n<div class=\"wp-block-custom-chromatogram-article-top\"><div class=\"chromatogram-article-placeholder\"><div class=\"figure-heading\"><strong>Figure 1:<\/strong> Indeno[123-cd]pyrene (left) extracted ion chromatogram showing good resolution from the dibenz[ah]anthracene interferences (right). Peak areas for [276+] are marking the apices.<\/div><div class='chromatogram-article-inner-full'><div class=\"chromatogram-article-inner\">\n<style>.kb-image76432_189f8c-cd .kb-image-has-overlay:after{opacity:0.3;}<\/style>\n<figure class=\"wp-block-kadence-image kb-image76432_189f8c-cd size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"398\" height=\"667\" src=\"https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-01.png\" alt=\"\" class=\"kb-img wp-image-78089\" title=\"-\" srcset=\"https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-01.png 398w, https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-01-179x300.png 179w\" sizes=\"auto, (max-width: 398px) 100vw, 398px\" \/><\/figure>\n\n<\/div><\/div><\/div>\n\n\n<p>So why do these two PAHs, which have different nominal masses, need to be chromatographically separated? Because&nbsp;<strong>DahA<\/strong>&nbsp;(nominal mass 278) has a very strong signal at m\/z = 276 (the nominal mass of&nbsp;<strong>IcdP<\/strong>) under electron ionization at 70eV. Coelution of these two compounds causes several problems with the analysis:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Calibration bias<\/li>\n\n\n\n<li>Mischaracterization of sample toxicity<\/li>\n\n\n\n<li>Misidentification of the&nbsp;<strong>DahA<\/strong>&nbsp;[276+] signal as&nbsp;<strong>IcdP<\/strong>&nbsp;(this is especially devastating during proficiency test studies)<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Calibration Bias<\/h2>\n\n\n\n<p>Let\u2019s look at an extracted ion chromatogram for<strong>&nbsp;IcdP<\/strong>&nbsp;where&nbsp;<strong>IcdP<\/strong>&nbsp;and&nbsp;<strong>DahA<\/strong>&nbsp;are well separated on the&nbsp;<strong>Rxi-SVOCms<\/strong>&nbsp;cat#16623&nbsp;(Figure 1 Were&nbsp;<strong>IcdP<\/strong>&nbsp;and&nbsp;<strong>DahA<\/strong>&nbsp;to coelute, the quant ion signal ([276+]) for&nbsp;<strong>IcdP<\/strong>&nbsp;would be inflated&nbsp;<strong>38.2%<\/strong>&nbsp;by&nbsp;<strong>DahA<\/strong>&nbsp;ions. Running a calibration under these conditions would cause a significant negative bias in the calculated value for&nbsp;<strong>IcdP<\/strong>&nbsp;concentration in a sample extract.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Mischaracterization of Sample Toxicity<\/h2>\n\n\n\n<p>A PAH mixture\u2019s toxicological profile is characterized using Potency Equivalency Factors (<strong>PEFs<\/strong>). Carcinogenicity is expressed as Benzo[a]pyrene (BaP) equivalent:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Indeno[123-cd]pyrene PEF = 0.1<\/li>\n\n\n\n<li>Dibenz[ah]anthracene PEF = 2.4<\/li>\n\n\n\n<li>Benzo[b]fluoranthene PEF = 0.1<\/li>\n\n\n\n<li>Benzo[k]fluoranthene PEF = 0.1<\/li>\n\n\n\n<li>Benzo[a]pyrene PEF = 1.0<\/li>\n<\/ul>\n\n\n\n<p><strong>IcdP<\/strong>\u2019s PEF is only 0.1 while&nbsp;<strong>DahA<\/strong>\u2019s is 2.4, so reporting&nbsp;<strong>IcdP<\/strong>\u2019s concentration in samples with a negative bias of nearly 40% shouldn\u2019t be&nbsp;<em>that<\/em>&nbsp;bad, right? The answer really depends on the relative abundance of each PAH in real samples. Let\u2019s look at the NIST SRM \u201cPAHs in Coal Tar\u201d analysis (Figure 2). In this case, IcdP contamination exceeds&nbsp;<strong>DahA<\/strong>&nbsp;by a large amount. Were this a food commodity being tested for PAHs, a near 40% low bias in the calculated value of a PAH with a high signal could be the difference between properly characterizing the food as unsafe for humans and a false negative allowing the commodity to be distributed.<\/p>\n\n\n<div class=\"wp-block-custom-chromatogram-article-top\"><div class=\"chromatogram-article-placeholder\"><div class=\"figure-heading\"><strong>Figure 2:<\/strong> Indeno[123-cd]pyrene and dibenz[ah]anthracene in NIST SRM 1597a (part of GC_EV1606)<\/div><div class='chromatogram-article-inner-full'><div class=\"chromatogram-article-inner\">\n<style>.kb-image76432_26545b-8d .kb-image-has-overlay:after{opacity:0.3;}<\/style>\n<figure class=\"wp-block-kadence-image kb-image76432_26545b-8d size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"505\" height=\"678\" src=\"https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-02.png\" alt=\"\" class=\"kb-img wp-image-78101\" title=\"-\" srcset=\"https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-02.png 505w, https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-02-223x300.png 223w\" sizes=\"auto, (max-width: 505px) 100vw, 505px\" \/><\/figure>\n\n<\/div><\/div><\/div>\n\n\n<h2 class=\"wp-block-heading\">Misidentification of the [276+] Ion Signal from Dibenz[ah]anthracene<\/h2>\n\n\n\n<p>This is the simplest situation, but it can lead to disastrous results. If&nbsp;<strong>IcdP<\/strong>&nbsp;and&nbsp;<strong>DahA<\/strong>&nbsp;coelute in your chromatographic run, and you receive a PT sample that contains&nbsp;<strong>DahA<\/strong>&nbsp;only at a moderately high level, you will be unable to tell if the [276+] is from&nbsp;<strong>DahA<\/strong>&nbsp;or&nbsp;<strong>IcdP<\/strong>. Misreport those compounds on consecutive PT rounds and the local regulating body will likely pull the certificate authorizing your laboratory to perform the analysis.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Recommended Analytical Conditions for the Rxi-SVOCms Column<\/h2>\n\n\n\n<p>Figure 3 shows the continuing calibration verification level (20 ng\/\u00b5L) from our 8-point calibration ranging from 1 ng\/\u00b5L to 120 ng\/\u00b5L, or 100 pg to 12 ng column loading for each of the 86 target compounds and surrogates on cat#16623 \u2013 a 30 m x 0.25 mm x 0.25 \u00b5m <strong>Rxi-SVOCms<\/strong>&nbsp;Column (GC_EV1604).<\/p>\n\n\n<div class=\"wp-block-custom-chromatogram-article-top\"><div class=\"chromatogram-article-placeholder\"><div class=\"figure-heading\"><strong>Figure 3:<\/strong> Example total ion chromatogram of a 94 component semivolatile standard injection with a 10:1 split injection and 2 ng column loading for each component<\/div><div class='chromatogram-article-inner-full'><div class=\"chromatogram-article-inner\">\n<style>.kb-image76432_34346e-a7 .kb-image-has-overlay:after{opacity:0.3;}<\/style>\n<figure class=\"wp-block-kadence-image kb-image76432_34346e-a7 size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"583\" src=\"https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-03-1024x583.png\" alt=\"\" class=\"kb-img wp-image-78095\" title=\"-\" srcset=\"https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-03-1024x583.png 1024w, https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-03-300x171.png 300w, https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-03-768x437.png 768w, https:\/\/discover.restek.com\/wp-content\/uploads\/blog-improved-indeno-123-cd-pyrene-dibenz-ah-anthracene-separation-on-the-new-RXI-SVOCMS-column-03.png 1265w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n<\/div><\/div><\/div>\n\n\n<p>Optimized for a 16-minute run, we get excellent resolution of both critical PAH pairs.&nbsp;<strong>86%<\/strong>&nbsp;valley as reported by MSD ChemStation for&nbsp;<strong>BbF<\/strong>&nbsp;and&nbsp;<strong>BkF<\/strong>&nbsp;and&nbsp;<strong>87%<\/strong>&nbsp;valley for&nbsp;<strong>IcdP<\/strong>&nbsp;and&nbsp;<strong>DahA<\/strong>. If 16 minutes isn\u2019t fast enough for your needs,&nbsp;tune in next time&nbsp;when I explain how to cut 5 minutes from the analysis time without sacrificing the critical separations.<\/p>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n","protected":false},"excerpt":{"rendered":"<p>When we started development of the Rxi-SVOCms column, we focused on maximizing the resolution of PAH isobars while targeting a 16-minute elution time for benzo[ghi]perylene (BghiP) on a 30 m x 0.25 mm x 0.25 &micro;m column using our optimized split injection SVOA acquisition parameters [GC_EV1604]. The benzo[b]fluoranthene &#8211; benzo[k]fluoranthene (BbF &#8211; BkF) separation draws the most attention, but we also put significant resources into maximizing the indeno[123-cd]pyrene &ndash; dibenz[ah]anthracene (IcdP &#8211; DahA) separation in the allotted time.<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"footnotes":""},"categories":[9],"tags":[],"industries-application":[],"post-badge":[],"resource-type":[],"product-library":[],"resource-technique":[],"ppma_author":[584],"class_list":["post-76432","post","type-post","status-publish","format-standard","hentry","category-blogs"],"acf":[],"taxonomy_info":{"category":[{"value":9,"label":"Blogs"}]},"featured_image_src_large":false,"author_info":{"display_name":"Brenda Cogan","author_link":"https:\/\/discover.restek.com\/ja\/author\/brenda-coganrestek-com\/"},"comment_info":0,"category_info":[{"term_id":9,"name":"Blogs","slug":"blogs","term_group":0,"term_taxonomy_id":9,"taxonomy":"category","description":"","parent":0,"count":444,"filter":"raw","cat_ID":9,"category_count":444,"category_description":"","cat_name":"Blogs","category_nicename":"blogs","category_parent":0}],"tag_info":false,"authors":[{"term_id":584,"user_id":0,"is_guest":1,"slug":"chris-rattray","display_name":"Chris Rattray","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/?s=96&d=mm&r=g","0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/posts\/76432","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/comments?post=76432"}],"version-history":[{"count":7,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/posts\/76432\/revisions"}],"predecessor-version":[{"id":85627,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/posts\/76432\/revisions\/85627"}],"wp:attachment":[{"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/media?parent=76432"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/categories?post=76432"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/tags?post=76432"},{"taxonomy":"industries-application","embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/industries-application?post=76432"},{"taxonomy":"post-badge","embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/post-badge?post=76432"},{"taxonomy":"resource-type","embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/resource-type?post=76432"},{"taxonomy":"product-library","embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/product-library?post=76432"},{"taxonomy":"resource-technique","embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/resource-technique?post=76432"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/discover.restek.com\/ja\/wp-json\/wp\/v2\/ppma_author?post=76432"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}