{"id":76448,"date":"2022-09-14T00:00:00","date_gmt":"2022-09-14T00:00:00","guid":{"rendered":"https:\/\/discover.restek.com\/?p=76448"},"modified":"2026-04-08T19:07:39","modified_gmt":"2026-04-08T19:07:39","slug":"pfas-interference-or-contamination","status":"publish","type":"post","link":"https:\/\/discover.restek.com\/it\/blogs-zh\/gnbl5525\/pfas-interference-or-contamination","title":{"rendered":"PFAS Interference or Contamination?"},"content":{"rendered":"\n

PFAS contaminants are everywhere in the world and, what is more concerning, in everyone. Recently, I came across an article describing the extent of the problem and that PFAS can be found in nearly all living humans (European teenagers are high \u2013 on PFAS \u2013 ChemSec<\/a>). The statement in the article that most resonated with me was this: \u201cIn general, we don\u2019t have a solution on how to stop the exposure to PFAS, as they are so persistent in the environment and humans.\u201d<\/p>\n\n\n\n

This gives us a better understanding why contamination with PFAS can be found all over our lab, vials, or other sample prep products. During method development, many analysts must address whether it is even possible to get a clean blank below the method detection limit (MDL). <\/p>\n\n\n\n

In this blog I would like to address another problematic PFAS. Recently our technical service group talked to many customers who reported contamination of 6:2 fluorotelomer sulfonic acid (6:2 FTS) and its surrogate sodium 1H,1H,2H,2H-perfluoro-1-(1,2-13C2)-octane sulfonate (M2-6:2 FTS) in variety of products (vials, SPE cartridges, and syringe filters). Our scientist tested all the products but were not able to confirm the contamination. Tested vials (catalog # 23246), SPE cartridges (catalog # 28470), and syringe filters (catalog # 23987) were not contaminated with 6:2 FTS.<\/p>\n\n\n\n

So, what were our customers seeing? It appears that the EPA has already solved the problem. EPA method 83271<\/sup> section 4.5 describes why labs may be detecting bias high for the 6:2 FTS and how to go around it:<\/p>\n\n\n\n

\u201cHigh concentrations of the native 4:2 FTS, 6:2 FTS, and 8:2 FTS target analytes will interfere with the primary product ion signals listed in section 17.0, Table 2 for the M2-4:2 FTS, M2-6:2 FTS and M2-8:2 FTS surrogates. This interference results from the natural abundance of the 34S isotope (~4.2% abundance relative to 32S) in the native FTS target analytes and can lead to high bias recovery of these surrogates. Using the secondary product ions identified in Table 2 for quantitation of these surrogates will minimize this interference because this surrogate product ion loses the 13C2-labeled fluorocarbon sidechain to produce 32SO3H- (m\/z 81), while the 34S isotope of the target analyte produces 34SO3H- (m\/z 83) from the same nominal mass precursor ion.\u201d Using the m\/z 81 product ion for quantitation of M2-4:2 FTS, M2-6:2 FTS, and M2-8:2 FTS will reduce interferences from high concentrations of the respective native target analytes compared to the primary ions. Example: use m\/z 429\/81 for the M2-6:2 FTS surrogate, and not m\/z 429\/409. \u201c<\/p>\n\n\n\n

(EPA method 8327, section 17.0, table 2
8327.pdf (epa.gov)<\/a><\/p>\n\n\n\n

We reviewed other available methods for the determination of PFAS and how they are treating the fluorotelomer bias. Here are our findings:<\/p>\n\n\n\n

Methods<\/td>\n

Compound<\/p>\n<\/td>

\n

1st<\/sup> MRM Transition<\/p>\n<\/td>

\n

2nd<\/sup> MRM Transition<\/p>\n<\/td>

Comments<\/td><\/tr>
EPA 1633 (2nd<\/sup> Draft method, June 2022)<\/td>\n

M2-6:2 FTS<\/p>\n<\/td>

\n

429.1 \u2192 80.9 (parent ion \u2192 quantification ion)<\/p>\n<\/td>

\n

429.1 \u2192 409.0 (parent ion \u2192 confirmation ion)<\/p>\n<\/td>

Switched quant ion and qual ion for labeled compound and analyte.<\/td><\/tr>
\n

6:2 FTS<\/p>\n<\/td>

\n

427.1 \u2192 407.0 (parent ion \u2192 quantification ion)<\/p>\n<\/td>

\n

427.1 \u2192 80.9 (parent ion \u2192 confirmation ion)<\/p>\n<\/td><\/tr>

EPA 533<\/td>\n

M2-6:2 FTS<\/p>\n<\/td>

\n

429 \u2192 409 (precursor ion \u2192 product ion)<\/p>\n<\/td>

\n

n\/a<\/p>\n<\/td>

\n

1st<\/sup> transition only for both analyte and labeled ISTD.<\/p>\n

No mention of interference nor second transition to monitor<\/p>\n<\/td><\/tr>

\n

6:2 FTS<\/p>\n<\/td>

\n

427 \u2192 407 (precursor ion \u2192 product ion)<\/p>\n<\/td>

\n

n\/a<\/p>\n<\/td><\/tr>

EPA 8327<\/td>\n

M2-6:2 FTS<\/p>\n<\/td>

\n

429 \u2192 409 (precursor \u2192 primary product ion)<\/p>\n<\/td>

\n

429 \u2192 81 (precursor \u2192 secondary product ion)<\/p>\n<\/td>

\n

No 2nd<\/sup> transition for labeled M2-6:2 FTS in their 2019 edition but added 2nd<\/sup> transition in their 2021 edition.<\/p>\n

Mentions recovery limits of 70 \u2013 130% might be too narrow for M2-6:2 FTS and some other compounds and the use of m\/z 81 for quantitation can reduce the interference.<\/p>\n<\/td><\/tr>

\n

6:2 FTS<\/p>\n<\/td>

\n

427 \u2192 407 (precursor \u2192 primary product ion)<\/p>\n<\/td>

\n

427 \u2192 81 (precursor \u2192 secondary product ion)<\/p>\n<\/td><\/tr>

EPA OTM-45<\/td>\n

M2-6:2 FTS<\/p>\n<\/td>

\n

429 \u2192 409 (precursor ion \u2192 primary product ion)<\/p>\n<\/td>

\n

429 \u2192 81(precursor ion \u2192 secondary product ion)<\/p>\n<\/td>

No 2nd<\/sup> transition for 6:2 FTS.<\/td><\/tr>
\n

6:2 FTS<\/p>\n<\/td>

\n

427 \u2192 407 (precursor ion \u2192 primary product ion)<\/p>\n<\/td>

\n

n\/a<\/p>\n<\/td><\/tr>

ISO 21675:2019<\/td>\n

M2-6:2 FTS<\/p>\n<\/td>

\n

429 \u2192 409 (precursor \u2192 quantifier)<\/p>\n<\/td>

\n

429 \u2192 81 (precursor \u2192 qualifier)<\/p>\n<\/td>

No switching quant ion and qual ion.<\/td><\/tr>
\n

6:2 FTS<\/p>\n<\/td>

\n

427 \u2192 407 (precursor \u2192 quantifier)<\/p>\n<\/td>

\n

427 \u2192 81 (precursor \u2192 qualifier)<\/p>\n<\/td><\/tr>

ASTM D7979-20<\/td>\n

M2-6:2 FTS<\/p>\n<\/td>

\n

429 \u2192 408.9 (primary transition)<\/p>\n<\/td>

\n

n\/a<\/p>\n<\/td>

No 2nd<\/sup> transition for labeled M2-6:2 FTS.<\/td><\/tr>
\n

6:2 FTS<\/p>\n<\/td>

\n

427 \u2192 406.9 (primary transition)<\/p>\n<\/td>

\n

427 \u2192 80.9 (confirmatory transition)<\/p>\n<\/td><\/tr>

ASTM D7968-17a<\/td>\n

M2-6:2 FTS<\/p>\n<\/td>

\n

429 \u2192 408.9 (primary transition)<\/p>\n<\/td>

\n

n\/a<\/p>\n<\/td>

No 2nd<\/sup> transition for labeled M2-6:2 FTS.<\/td><\/tr>
\n

6:2 FTS<\/p>\n<\/td>

\n

427 \u2192 406.9 (primary transition)<\/p>\n<\/td>

\n

427 \u2192 80.9 (confirmatory transition)<\/p>\n<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

**Note that the methods are being constantly updated. Always work with the latest version.<\/em><\/p>\n\n\n\n

1<\/sup>Method 8327: Per- and Polyfluoroalkyl Substances (PFAS) by Liquid Chromatography\/Tandem Mass Spectrometry (LC\/MS\/MS)<\/p>\n\n\n\n

<\/div>\n","protected":false},"excerpt":{"rendered":"

PFAS contaminants are everywhere in the world and, what is more concerning, in everyone. Recently, I came across an article describing the extent of the problem and that PFAS can be found in nearly all living humans (European teenagers are high – on PFAS – ChemSec). The statement in the article that most resonated with me was this: “In general, we don’t have a solution on how to stop the exposure to PFAS, as they are so persistent in the environment and humans.”<\/p>\n","protected":false},"author":33,"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":[790],"tags":[2782],"industries-application":[2189],"post-badge":[],"resource-type":[],"product-library":[],"resource-technique":[],"ppma_author":[453,601],"class_list":["post-76448","post","type-post","status-publish","format-standard","hentry","category-blogs-zh","tag-pfas","industries-application-pfas-testing-zh"],"acf":[],"taxonomy_info":{"category":[{"value":790,"label":"\u535a\u5ba2"}],"post_tag":[{"value":2782,"label":"PFAS"}],"industries-application":[{"value":2189,"label":"PFAS\u68c0\u6d4b"}]},"featured_image_src_large":false,"author_info":{"display_name":"Gary Oden","author_link":"https:\/\/discover.restek.com\/it\/author\/gary-oden\/"},"comment_info":0,"category_info":[{"term_id":790,"name":"\u535a\u5ba2","slug":"blogs-zh","term_group":0,"term_taxonomy_id":790,"taxonomy":"category","description":"","parent":0,"count":438,"filter":"raw","cat_ID":790,"category_count":438,"category_description":"","cat_name":"\u535a\u5ba2","category_nicename":"blogs-zh","category_parent":0}],"tag_info":[{"term_id":2782,"name":"PFAS","slug":"pfas","term_group":0,"term_taxonomy_id":2782,"taxonomy":"post_tag","description":"","parent":0,"count":46,"filter":"raw"}],"authors":[{"term_id":453,"user_id":33,"is_guest":0,"slug":"gary-oden","display_name":"Gary Oden","avatar_url":{"url":"https:\/\/discover.restek.com\/wp-content\/uploads\/people-oden-gary.jpg","url2x":"https:\/\/discover.restek.com\/wp-content\/uploads\/people-oden-gary.jpg"},"0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""},{"term_id":601,"user_id":0,"is_guest":1,"slug":"mike-chang","display_name":"Mike Chang","avatar_url":{"url":"https:\/\/discover.restek.com\/wp-content\/uploads\/people-square-chang-mike.jpg","url2x":"https:\/\/discover.restek.com\/wp-content\/uploads\/people-square-chang-mike.jpg"},"0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/posts\/76448","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/users\/33"}],"replies":[{"embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/comments?post=76448"}],"version-history":[{"count":2,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/posts\/76448\/revisions"}],"predecessor-version":[{"id":92302,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/posts\/76448\/revisions\/92302"}],"wp:attachment":[{"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/media?parent=76448"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/categories?post=76448"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/tags?post=76448"},{"taxonomy":"industries-application","embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/industries-application?post=76448"},{"taxonomy":"post-badge","embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/post-badge?post=76448"},{"taxonomy":"resource-type","embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/resource-type?post=76448"},{"taxonomy":"product-library","embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/product-library?post=76448"},{"taxonomy":"resource-technique","embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/resource-technique?post=76448"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/discover.restek.com\/it\/wp-json\/wp\/v2\/ppma_author?post=76448"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}