Comparison of Chromatographic and Solid-Phase Extraction-Based Methods for the Analysis of Selected Perfluoroalkyl Compounds

Project no. 29548 · Status: Kapanmış (Yayın bekleniyor) · 2023

Summary

<p>Persistent&nbsp;organic&nbsp;pollutants&nbsp;(POPs),&nbsp;which&nbsp;accumulate&nbsp;in&nbsp;the&nbsp;environment&nbsp;over&nbsp;many&nbsp;years&nbsp;and&nbsp;exhibit&nbsp;harmful&nbsp;effects,&nbsp;are&nbsp;a&nbsp;significant&nbsp;class&nbsp;of&nbsp;pollutants&nbsp;that&nbsp;require&nbsp;control&nbsp;due&nbsp;to&nbsp;their&nbsp;negative&nbsp;impacts&nbsp;on&nbsp;human&nbsp;and&nbsp;environmental&nbsp;health.&nbsp;Among&nbsp;these&nbsp;compounds,&nbsp;per-&nbsp;and&nbsp;polyfluoroalkyl&nbsp;substances&nbsp;(PFAS),&nbsp;whose&nbsp;adverse&nbsp;effects&nbsp;have&nbsp;become&nbsp;better&nbsp;understood&nbsp;in&nbsp;recent&nbsp;years,&nbsp;are&nbsp;gaining&nbsp;increasing&nbsp;importance.&nbsp;These&nbsp;compounds,&nbsp;which&nbsp;contain&nbsp;a&nbsp;hydroxyl,&nbsp;carboxyl,&nbsp;or&nbsp;sulfo&nbsp;group&nbsp;at&nbsp;the&nbsp;end&nbsp;of&nbsp;an&nbsp;alkyl&nbsp;chain&nbsp;substituted&nbsp;with&nbsp;fluorine,&nbsp;are&nbsp;widely&nbsp;used&nbsp;in&nbsp;waterproof&nbsp;textiles,&nbsp;cosmetics,&nbsp;and&nbsp;food&nbsp;packaging&nbsp;materials&nbsp;due&nbsp;to&nbsp;their&nbsp;hydrophilic&nbsp;and&nbsp;lipophobic&nbsp;groups.&nbsp;</p><p>Due&nbsp;to&nbsp;their&nbsp;high&nbsp;thermal&nbsp;resistance&nbsp;resulting&nbsp;from&nbsp;the&nbsp;strength&nbsp;of&nbsp;C-F&nbsp;bonds,&nbsp;they&nbsp;are&nbsp;used&nbsp;in&nbsp;fire&nbsp;extinguishers,&nbsp;in&nbsp;the&nbsp;production&nbsp;of&nbsp;non-combustible&nbsp;pans,&nbsp;and&nbsp;also&nbsp;for&nbsp;various&nbsp;purposes&nbsp;in&nbsp;the&nbsp;military,&nbsp;aviation,&nbsp;and&nbsp;electronics&nbsp;industries.&nbsp;Due&nbsp;to&nbsp;their&nbsp;thermal&nbsp;and&nbsp;chemical&nbsp;resistance,&nbsp;PFAS&nbsp;compounds,&nbsp;also&nbsp;known&nbsp;as&nbsp;perpetual&nbsp;chemicals,&nbsp;can&nbsp;remain&nbsp;in&nbsp;the&nbsp;environment&nbsp;for&nbsp;extended&nbsp;periods.&nbsp;Perfluorooctanoic&nbsp;acid&nbsp;(PFOA)&nbsp;and&nbsp;perfluorooctan&nbsp;sulfonic&nbsp;acid&nbsp;(PFOS)&nbsp;were&nbsp;the&nbsp;earliest&nbsp;compounds&nbsp;included&nbsp;in&nbsp;the&nbsp;Stockholm&nbsp;Convention's&nbsp;list&nbsp;of&nbsp;priority&nbsp;hazardous&nbsp;substances&nbsp;in&nbsp;2013.&nbsp;Later,&nbsp;shorter-chain&nbsp;equivalents&nbsp;were&nbsp;added&nbsp;to&nbsp;this&nbsp;list,&nbsp;and&nbsp;EU&nbsp;regulations&nbsp;established&nbsp;limit&nbsp;values&nbsp;of&nbsp;100&nbsp;ng/L&nbsp;for&nbsp;each&nbsp;PFAS&nbsp;compound&nbsp;and&nbsp;500&nbsp;ng/L&nbsp;for&nbsp;the&nbsp;total.&nbsp;Emphasis&nbsp;is&nbsp;placed&nbsp;on&nbsp;developing&nbsp;methods&nbsp;for&nbsp;the&nbsp;sensitive&nbsp;and&nbsp;reliable&nbsp;analysis&nbsp;of&nbsp;these&nbsp;compounds&nbsp;in&nbsp;drinking&nbsp;water&nbsp;and&nbsp;surface&nbsp;waters.&nbsp;In&nbsp;our&nbsp;country,&nbsp;in&nbsp;line&nbsp;with&nbsp;EU&nbsp;guidelines,&nbsp;the&nbsp;presence&nbsp;of&nbsp;PFOA&nbsp;and&nbsp;PFOS,&nbsp;whose&nbsp;production&nbsp;and&nbsp;use&nbsp;are&nbsp;prohibited,&nbsp;in&nbsp;drinking&nbsp;water&nbsp;poses&nbsp;a&nbsp;threat&nbsp;to&nbsp;human&nbsp;health.&nbsp;</p><p></p><p>The&nbsp;present&nbsp;thesis&nbsp;primarily&nbsp;explores&nbsp;alternative&nbsp;methods&nbsp;that&nbsp;can&nbsp;be&nbsp;used&nbsp;in&nbsp;conjunction&nbsp;with&nbsp;the&nbsp;standard&nbsp;SPE-LC-MS/MS&nbsp;method&nbsp;for&nbsp;the&nbsp;determination&nbsp;of&nbsp;PFOS&nbsp;and&nbsp;PFOA.&nbsp;The&nbsp;interference&nbsp;effects&nbsp;of&nbsp;shorter-chain&nbsp;compounds&nbsp;such&nbsp;as&nbsp;perfluoroheptanoic&nbsp;acid&nbsp;(PFHxA)&nbsp;and&nbsp;perfluorohexanoic&nbsp;acid&nbsp;(PFHpA)&nbsp;will&nbsp;also&nbsp;be&nbsp;discussed.</p><p>This&nbsp;thesis&nbsp;consists&nbsp;of&nbsp;three&nbsp;main&nbsp;sections.&nbsp;In&nbsp;the&nbsp;first&nbsp;section,&nbsp;focus&nbsp;was&nbsp;on&nbsp;the&nbsp;method&nbsp;development&nbsp;for&nbsp;direct&nbsp;injection&nbsp;of&nbsp;standard&nbsp;solutions&nbsp;containing&nbsp;the&nbsp;two&nbsp;target&nbsp;analytes&nbsp;and&nbsp;two&nbsp;potentially&nbsp;interfering&nbsp;compounds,&nbsp;along&nbsp;with&nbsp;the&nbsp;internal&nbsp;standard,&nbsp;into&nbsp;an&nbsp;LC-MS/MS&nbsp;system.&nbsp;The&nbsp;gradient&nbsp;program&nbsp;and&nbsp;measurement&nbsp;conditions&nbsp;were&nbsp;kept&nbsp;constant&nbsp;across&nbsp;the&nbsp;methods&nbsp;used,&nbsp;but&nbsp;the&nbsp;mobile&nbsp;phase&nbsp;differed.&nbsp;In&nbsp;the&nbsp;first&nbsp;method,&nbsp;an&nbsp;aqueous&nbsp;formic&nbsp;acid&nbsp;solution&nbsp;in&nbsp;acetonitrile&nbsp;was&nbsp;used,&nbsp;and&nbsp;the&nbsp;analysis&nbsp;was&nbsp;performed&nbsp;on&nbsp;a&nbsp;C8&nbsp;column.&nbsp;</p><p>The&nbsp;second&nbsp;method&nbsp;is&nbsp;the&nbsp;EPA-533&nbsp;standard&nbsp;method,&nbsp;performed&nbsp;on&nbsp;a&nbsp;C18&nbsp;column&nbsp;with&nbsp;ammonium&nbsp;acetate&nbsp;and&nbsp;methanol&nbsp;as&nbsp;the&nbsp;mobile&nbsp;phase.&nbsp;To&nbsp;minimize&nbsp;differences&nbsp;that&nbsp;might&nbsp;arise&nbsp;from&nbsp;the&nbsp;column&nbsp;used,&nbsp;both&nbsp;methods&nbsp;were&nbsp;repeated&nbsp;with&nbsp;both&nbsp;columns.&nbsp;The&nbsp;third&nbsp;method&nbsp;is&nbsp;a&nbsp;modification&nbsp;of&nbsp;the&nbsp;standard&nbsp;method,&nbsp;in&nbsp;which&nbsp;ammonium&nbsp;formate&nbsp;solutions&nbsp;were&nbsp;used&nbsp;as&nbsp;the&nbsp;mobile&nbsp;phase.&nbsp;Based&nbsp;on&nbsp;the&nbsp;data&nbsp;obtained&nbsp;for&nbsp;the&nbsp;targeted&nbsp;analytes,&nbsp;their&nbsp;analytical&nbsp;properties&nbsp;were&nbsp;compared.&nbsp;LOD&nbsp;values&nbsp;were&nbsp;calculated&nbsp;using&nbsp;different&nbsp;methods,&nbsp;and&nbsp;the&nbsp;results&nbsp;were&nbsp;evaluated.</p><p>The&nbsp;second&nbsp;part&nbsp;of&nbsp;the&nbsp;thesis&nbsp;examines&nbsp;the&nbsp;SPE-LC-MS/MS&nbsp;method&nbsp;using&nbsp;a&nbsp;WAX&nbsp;cartridge&nbsp;for&nbsp;pre-separation&nbsp;and&nbsp;enrichment.&nbsp;Recovery&nbsp;values&nbsp;were&nbsp;calculated&nbsp;from&nbsp;analyses&nbsp;conducted&nbsp;over&nbsp;a&nbsp;wide&nbsp;concentration&nbsp;range,&nbsp;and&nbsp;this&nbsp;method&nbsp;was&nbsp;applied&nbsp;to&nbsp;tap&nbsp;water&nbsp;samples.&nbsp;</p><p>The&nbsp;third&nbsp;and&nbsp;final&nbsp;part&nbsp;of&nbsp;the&nbsp;thesis&nbsp;focuses&nbsp;on&nbsp;the&nbsp;production&nbsp;and&nbsp;use&nbsp;of&nbsp;lab-made&nbsp;SPME.&nbsp;Anodized&nbsp;titanium&nbsp;wire&nbsp;was&nbsp;used&nbsp;as&nbsp;the&nbsp;fiber&nbsp;support&nbsp;material&nbsp;and&nbsp;modified&nbsp;with&nbsp;appropriate&nbsp;reagents&nbsp;to&nbsp;impart&nbsp;anion-exchange&nbsp;properties.&nbsp;The&nbsp;efficiency&nbsp;of&nbsp;this&nbsp;fiber&nbsp;in&nbsp;the&nbsp;pre-concentration&nbsp;and&nbsp;determination&nbsp;of&nbsp;selected&nbsp;PFAS&nbsp;compounds&nbsp;was&nbsp;investigated.&nbsp;In&nbsp;conclusion,&nbsp;this&nbsp;thesis&nbsp;presents&nbsp;results&nbsp;that&nbsp;will&nbsp;make&nbsp;a&nbsp;significant&nbsp;contribution&nbsp;to&nbsp;the&nbsp;limited&nbsp;number&nbsp;of&nbsp;studies&nbsp;conducted&nbsp;in&nbsp;this&nbsp;field&nbsp;in&nbsp;our&nbsp;country.</p>

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