{"id":6891,"date":"2026-04-24T12:15:47","date_gmt":"2026-04-24T12:15:47","guid":{"rendered":"https:\/\/www.waters.com\/blog\/?p=6891"},"modified":"2026-04-24T12:22:14","modified_gmt":"2026-04-24T12:22:14","slug":"two-truths-and-a-lie-about-solid-core-particle-efficiency","status":"publish","type":"post","link":"https:\/\/www.waters.com\/blog\/two-truths-and-a-lie-about-solid-core-particle-efficiency\/","title":{"rendered":"Two Truths and a Lie About Solid\u2011Core Particle Efficiency"},"content":{"rendered":"\n<p>Solid\u2011core (or superficially porous) particles are the foundation of <a href=\"https:\/\/www.waters.com\/nextgen\/global\/products\/columns\/cortecs-premier-columns.html?xcid=o-o_35064\">solid core HPLC columns<\/a> and have earned a reputation for delivering higher efficiency separations than similarly sized, fully porous particles. Chromatographers see this play out repeatedly across small- and large-molecule applications under a wide range of operating conditions.<\/p>\n\n\n\n<p>But <em>why<\/em> solid\u2011core particles are more efficient is often misunderstood.<\/p>\n\n\n\n<p>Let\u2019s separate reality from misconception with two truths and a lie about solid\u2011core particle efficiency.<\/p>\n\n\n<style>.wp-block-kadence-spacer.kt-block-spacer-6891_90fb2c-2e .kt-block-spacer{height:60px;}.wp-block-kadence-spacer.kt-block-spacer-6891_90fb2c-2e .kt-divider{border-top-width:1px;height:1px;border-top-color:#eee;width:80%;border-top-style:solid;}<\/style>\n<div class=\"wp-block-kadence-spacer aligncenter kt-block-spacer-6891_90fb2c-2e\"><div class=\"kt-block-spacer kt-block-spacer-halign-center\"><hr class=\"kt-divider\"\/><\/div><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Truth #1: Longitudinal diffusion plays a major role &#8211; but not for the reason you might think<\/strong><\/h2>\n\n\n\n<p>Yes, solid\u2011core particles exhibit reduced longitudinal diffusion. But the reason has little to do with a shorter diffusion path length.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>The real driver is the mobile phase volume inside the particle.<\/strong><\/h3>\n\n\n\n<p>In a fully porous particle, analytes can diffuse throughout the entire internal pore volume. That gives the sample band more space to spread out along the column length.<\/p>\n\n\n\n<p>In contrast, a solid\u2011core particle contains an impermeable core, which dramatically reduces the volume inside the particle that is accessible to the mobile phase. With less internal space for analytes to explore, longitudinal diffusion is naturally limited.<\/p>\n\n\n\n<p>The result:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Less band broadening<\/li>\n\n\n\n<li>Sharper peaks<\/li>\n\n\n\n<li>Higher efficiency\u2014especially for small molecules operating at or below the optimum flow rate<\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img decoding=\"async\" width=\"1024\" height=\"826\" src=\"https:\/\/www.waters.com\/blog\/wp-content\/uploads\/cortecs-premier-molecule-graphic_full-res-presentation-ready-jpg-1024x826.jpeg\" alt=\"cortecs premier molecule graphic full res presentation ready jpg\" class=\"wp-image-6896\" style=\"width:500px\" srcset=\"https:\/\/www.waters.com\/blog\/wp-content\/uploads\/cortecs-premier-molecule-graphic_full-res-presentation-ready-jpg-1024x826.jpeg 1024w, https:\/\/www.waters.com\/blog\/wp-content\/uploads\/cortecs-premier-molecule-graphic_full-res-presentation-ready-jpg-300x242.jpeg 300w, https:\/\/www.waters.com\/blog\/wp-content\/uploads\/cortecs-premier-molecule-graphic_full-res-presentation-ready-jpg-768x619.jpeg 768w, https:\/\/www.waters.com\/blog\/wp-content\/uploads\/cortecs-premier-molecule-graphic_full-res-presentation-ready-jpg.jpeg 1270w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\"><em>Solid-core particles contain an impermeable core that is not accessible to the mobile phase.<\/em><\/figcaption><\/figure>\n<\/div>\n\n<style>.wp-block-kadence-spacer.kt-block-spacer-6891_e7d9aa-2d .kt-block-spacer{height:60px;}.wp-block-kadence-spacer.kt-block-spacer-6891_e7d9aa-2d .kt-divider{border-top-width:1px;height:1px;border-top-color:#eee;width:80%;border-top-style:solid;}<\/style>\n<div class=\"wp-block-kadence-spacer aligncenter kt-block-spacer-6891_e7d9aa-2d\"><div class=\"kt-block-spacer kt-block-spacer-halign-center\"><hr class=\"kt-divider\"\/><\/div><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Truth #2: Eddy dispersion, particle morphology, and packing uniformity significantly impact efficiency<\/strong><\/h2>\n\n\n\n<p>One of the most underestimated contributors to efficiency is how particles pack inside the column.<\/p>\n\n\n\n<p>In any packed bed, the structure near the column wall differs from that in the center. These structural differences create variations in flow velocity across the column radius, which contribute to eddy dispersion.<\/p>\n\n\n\n<p>This is where solid\u2011core particles used within solid core HPLC columns have an advantage.<\/p>\n\n\n\n<p>Because of their surface characteristics, particularly increased surface roughness, solid\u2011core particles pack more uniformly across the column diameter than smoother, fully porous particles. A more homogeneous packed bed leads to:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A more consistent flow velocity profile<\/li>\n\n\n\n<li>Reduced radial heterogeneity<\/li>\n\n\n\n<li>Less band broadening caused by eddy dispersion<\/li>\n<\/ul>\n\n\n\n<p>This improved packing uniformity can make a meaningful contribution to efficiency gains.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img decoding=\"async\" width=\"1024\" height=\"477\" src=\"https:\/\/www.waters.com\/blog\/wp-content\/uploads\/eddy-dispersion-1024x477.png\" alt=\"eddy dispersion\" class=\"wp-image-6897\" style=\"width:600px\" srcset=\"https:\/\/www.waters.com\/blog\/wp-content\/uploads\/eddy-dispersion-1024x477.png 1024w, https:\/\/www.waters.com\/blog\/wp-content\/uploads\/eddy-dispersion-300x140.png 300w, https:\/\/www.waters.com\/blog\/wp-content\/uploads\/eddy-dispersion-768x358.png 768w, https:\/\/www.waters.com\/blog\/wp-content\/uploads\/eddy-dispersion.png 1170w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\"><em>Less internal mobile-phase volume means less diffusion, sharper peaks, and higher efficiency.<\/em><\/figcaption><\/figure>\n<\/div>\n\n<style>.wp-block-kadence-spacer.kt-block-spacer-6891_2da774-8f .kt-block-spacer{height:60px;}.wp-block-kadence-spacer.kt-block-spacer-6891_2da774-8f .kt-divider{border-top-width:1px;height:1px;border-top-color:#eee;width:80%;border-top-style:solid;}<\/style>\n<div class=\"wp-block-kadence-spacer aligncenter kt-block-spacer-6891_2da774-8f\"><div class=\"kt-block-spacer kt-block-spacer-halign-center\"><hr class=\"kt-divider\"\/><\/div><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>The Lie: Solid\u2011core particles are more efficient because they significantly reduce mass transfer resistance<\/strong><\/h2>\n\n\n\n<p>This is more of a misconception than an outright lie. Mass transfer plays a smaller role in solid-core efficiency than it is usually credited with.<\/p>\n\n\n\n<p>The argument goes like this: solid\u2011core particles have a thin, porous layer around a solid core, which shortens the diffusion path inside the particle, which in turn reduces the mass transfer resistance for the analyte (the C-term in the Van Deemter equation).<\/p>\n\n\n\n<p>Shorter path equals less mass transfer resistance, which equals higher efficiency.<\/p>\n\n\n\n<p>That sounds reasonable, but it doesn\u2019t hold up when you look at the data closely.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>For small molecules<\/strong>: Mass\u2011transfer resistance is already very low for <em>both<\/em> fully porous and solid\u2011core particles. At typical flow rates, differences in solid\u2011to\u2011liquid mass transfer are negligible \u2014 certainly not large enough to explain the consistently higher efficiency observed with solid\u2011core materials.<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>For large molecules<\/strong>: It <em>is<\/em> true that shorter diffusion paths in the porous shell can improve mass transfer. However, even in this case, mass transfer is not the only contributor to the overall efficiency gain.<\/li>\n<\/ul>\n\n\n\n<p>So, while reduced mass transfer resistance exists, it plays a relatively small role in the improved efficiency of a solid\u2011core particle.<\/p>\n\n\n<style>.wp-block-kadence-spacer.kt-block-spacer-6891_3d8784-ff .kt-block-spacer{height:60px;}.wp-block-kadence-spacer.kt-block-spacer-6891_3d8784-ff .kt-divider{border-top-width:1px;height:1px;border-top-color:#eee;width:80%;border-top-style:solid;}<\/style>\n<div class=\"wp-block-kadence-spacer aligncenter kt-block-spacer-6891_3d8784-ff\"><div class=\"kt-block-spacer kt-block-spacer-halign-center\"><hr class=\"kt-divider\"\/><\/div><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>The bottom line<\/strong><\/h2>\n\n\n\n<p>When you put everything together, the efficiency advantage of solid\u2011core particles comes down to two main contributors:<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>Eddy dispersion<\/strong> &#8211; More uniform packing leads to a more consistent flow profile distribution and reduced band broadening.<\/li>\n\n\n\n<li><strong>Longitudinal diffusion<\/strong> &#8211; Reduced mobile phase volume inside the particle limits band broadening and sharpens peaks.<\/li>\n<\/ol>\n\n\n\n<p>Mass transfer can contribute to efficiency, but it is not the primary driver of solid-core particle performance. Shorter diffusion paths in the porous shell can reduce mass transfer resistance for large molecules, but for small molecules this impact is minimal.<\/p>\n\n\n\n<p>So, the next time someone says solid\u2011core particles are more efficient <em>because<\/em> of improved mass transfer, you\u2019ll know the truth!<\/p>\n\n\n<style>.wp-block-kadence-spacer.kt-block-spacer-6891_25704a-01 .kt-block-spacer{height:60px;}.wp-block-kadence-spacer.kt-block-spacer-6891_25704a-01 .kt-divider{border-top-width:1px;height:1px;border-top-color:#eee;width:80%;border-top-style:solid;}<\/style>\n<div class=\"wp-block-kadence-spacer aligncenter kt-block-spacer-6891_25704a-01\"><div class=\"kt-block-spacer kt-block-spacer-halign-center\"><hr class=\"kt-divider\"\/><\/div><\/div>\n\n\n\n<p>For more on the benefits of solid-core particles, check out the following resources:<\/p>\n\n\n\n<p><strong>Infographic: <\/strong><a href=\"https:\/\/www.waters.com\/nextgen\/global\/library\/library-details.html?documentid=720009148&amp;xcid=o-o_35065\">Upgrading to Solid-Core Particles<\/a><\/p>\n\n\n\n<p><strong>Video:<\/strong> <a href=\"https:\/\/videos.waters.com\/detail\/video\/6392496053112\/what-drives-higher-efficiency-in-solid-core-columns?q=Cortecs&amp;xcid=o-o_35066\">What Drives Higher Efficiency in Solid-Core Columns?<\/a><\/p>\n\n\n\n<p><strong>Application Note:<\/strong> <a href=\"https:\/\/www.waters.com\/nextgen\/global\/library\/application-notes\/2023\/improving-separation-efficiency-with-cortecs-premier-columns-that-feature-solid-core-particles-and-maxpeak-premier-hps-technology.html?xcid=o-o_35067\">Improving Separation Efficiency with CORTECS Premier Columns that Feature Solid-Core Particles<\/a><\/p>\n\n\n\n<p><strong>Blog Post:<\/strong> <a href=\"http:\/\/waters.com\/blog\/packed-bed-density-columns\/\" data-type=\"link\" data-id=\"http:\/\/waters.com\/blog\/packed-bed-density-columns\/\">The Quest for Maximum LC Performance<\/a><\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Solid\u2011core (or superficially porous) particles are the foundation of solid core HPLC columns and have earned a reputation for delivering higher efficiency separations than similarly sized, fully porous particles. Chromatographers see this play out repeatedly across small- and large-molecule applications under a wide range of operating conditions. But why solid\u2011core particles are more efficient is&#8230;<\/p>\n","protected":false},"author":176,"featured_media":926,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_robots_primary_cat":"none","_seopress_titles_title":"Solid Core Particle Efficiency Explained | Truths and Misconceptions","_seopress_titles_desc":"Discover what really drives solid core particle efficiency and why reduced longitudinal diffusion and eddy dispersion matter more than mass transfer.","_seopress_robots_index":"","_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_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,"_kad_post_classname":"","footnotes":""},"categories":[599,22],"tags":[148,104,315,629,774],"class_list":["post-6891","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-featured","category-technology","tag-analytical-chemists","tag-liquid-chromatography-lc","tag-pharma-qc","tag-pharmaceutical","tag-solid-core-particles"],"acf":[],"taxonomy_info":{"category":[{"value":599,"label":"Featured"},{"value":22,"label":"Technology"}],"post_tag":[{"value":148,"label":"analytical chemists"},{"value":104,"label":"liquid chromatography (LC)"},{"value":315,"label":"pharma QC"},{"value":629,"label":"pharmaceutical"},{"value":774,"label":"solid-core particles"}]},"featured_image_src_large":["https:\/\/www.waters.com\/blog\/wp-content\/uploads\/columns-1024x532.png",1024,532,true],"author_info":{"display_name":"Maureen DeLoffi","author_link":"https:\/\/www.waters.com\/blog\/author\/mdeloffi\/"},"comment_info":"","category_info":[{"term_id":599,"name":"Featured","slug":"featured","term_group":0,"term_taxonomy_id":599,"taxonomy":"category","description":"","parent":0,"count":28,"filter":"raw","term_order":"0","cat_ID":599,"category_count":28,"category_description":"","cat_name":"Featured","category_nicename":"featured","category_parent":0},{"term_id":22,"name":"Technology","slug":"technology","term_group":0,"term_taxonomy_id":22,"taxonomy":"category","description":"Our expertise drives innovation, development, and\u00a0application of informatics and software that continue to enable leading pharmaceutical, environmental, food &amp; beverage and chemical materials organizations to accelerate decision-making, improve laboratory effectiveness, and get products to market faster.","parent":0,"count":114,"filter":"raw","term_order":"0","cat_ID":22,"category_count":114,"category_description":"Our expertise drives innovation, development, and\u00a0application of informatics and software that continue to enable leading pharmaceutical, environmental, food &amp; beverage and chemical materials organizations to accelerate decision-making, improve laboratory effectiveness, and get products to market faster.","cat_name":"Technology","category_nicename":"technology","category_parent":0}],"tag_info":[{"term_id":148,"name":"analytical chemists","slug":"analytical-chemists","term_group":0,"term_taxonomy_id":148,"taxonomy":"post_tag","description":"","parent":0,"count":4,"filter":"raw","term_order":"0"},{"term_id":104,"name":"liquid chromatography (LC)","slug":"liquid-chromatography-lc","term_group":0,"term_taxonomy_id":104,"taxonomy":"post_tag","description":"","parent":0,"count":25,"filter":"raw","term_order":"0"},{"term_id":315,"name":"pharma QC","slug":"pharma-qc","term_group":0,"term_taxonomy_id":315,"taxonomy":"post_tag","description":"","parent":0,"count":8,"filter":"raw","term_order":"0"},{"term_id":629,"name":"pharmaceutical","slug":"pharmaceutical","term_group":0,"term_taxonomy_id":629,"taxonomy":"post_tag","description":"","parent":0,"count":7,"filter":"raw","term_order":"0"},{"term_id":774,"name":"solid-core particles","slug":"solid-core-particles","term_group":0,"term_taxonomy_id":774,"taxonomy":"post_tag","description":"","parent":0,"count":1,"filter":"raw","term_order":"0"}],"_links":{"self":[{"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/posts\/6891","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/users\/176"}],"replies":[{"embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/comments?post=6891"}],"version-history":[{"count":0,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/posts\/6891\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/media\/926"}],"wp:attachment":[{"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/media?parent=6891"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/categories?post=6891"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/tags?post=6891"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}