Sample Preparation Strategies for Water Analysis

1 2007 Waters CorporationSample Preparation Strategies Sample Preparation Strategies for Water Analysisfor Water AnalysisHannah WhiteHannah WhiteWaters Business Development ManagerWaters Business Development Manager 2007 Waters Corporation 2 OutlineOutline Introduction Why Sample Prep ConsiderationsoChoices of tools Why SPEoPre-Treatment Strategies Traditional approaches Modern approaches oMixed ModeoReverse phase Summary Appendix 2007 Waters Corporation 3 For high sensitivity analyses, such as those employing LC/MS/MS, proper Sample preparationcan be critical for minimizing matrix effects and concentrating analytes of Sample Prep?

2 Why Sample Prep?60% of the work activity and operating cost is spent on Sample Preparation for introduction into the analytical systemThree Purposes: Removes interferences from Sample matrix Concentrating analytes of interest Improving analytical system performances 2007 Waters Corporation 4 Sample Preparation TechniquesSample Preparation Techniques Sample Preparation - The simplification of Sample matrix and enrichment of target analyte(s) Types of Sample Prep include: Dilution Centrifugation Filtration Liquid/Liquid Extraction Solid Phase Extraction 2007 Waters Corporation 5 Some ConsiderationsSome Considerations Solid samples usually start with organic or aqueous extract of tissue or soil initial extract is adjusted for optimal SPE enrichment and/or cleanupopH adjustmentosolvent adjustment acetone/acetonitrile/IPA suitable for aqueous dilution, Reversed-Phase and Mixed-Mode SPE ethyl acetate/DCM/MTBE can be exchanged to hexane for normal-phase SPE Aqueous samples ( Water , beverage, plasma/urine)

3 Pretreatment may be appropriateopH adjustmentofiltration/centrifugationopro tein precipitation Usually, aqueous samples can be analyzed using Oasis Reversed-Phase or Mixed-Mode SPE 2007 Waters Corporation 6 PrePre--Treatment Prior to SPET reatment Prior to SPEPre treatment: Solid samples (soil, tissue, etc.) shake, sonicate or soxhletoextract with polar organic solvent (methanol, acetonitrile); polarsoextract with organic solvent + drying agent (DCM, acetone); non-polars, multi-residue Non aqueous Liquidoif Water soluble, dilute with Water for reversed-phase (or mixed-mode) SPEoif hexane soluble, dilute with or exchange to hexane for NP-SPE Wastewater filter or centrifuge as necessaryofiltered solids and filter may require Analysis as solids 2007 Waters Corporation 7 Why Solid Phase ExtractionWhy Solid Phase Extraction Isolation of the analyte(s) of interest from the matrix Sample Cleanup removal of matrix interference Increased sensitivityoIncreased system uptimeoLonger column lifetime Enrichment of analyte(s)

4 Of interest oIncreased sensitivity Exchange to LC or GC compatible solventSPE is also faster and more suitable for automation compared with liquid-liquid extraction 2007 Waters Corporation 8 Short List of sorbent Types Short List of sorbent Types for SPEfor SPE Normal-Phase Sorbents (polar sorbents) Silica, Alumina, Florisil , Aminopropyl silica, Diol silica, GCB Reversed-Phase Sorbents (non-polar sorbents) Oasis HLB C18, C8 etc (alkyl silica's) Carbon based sorbents Ion Exchange Accell Plus CM, QMA Mixed Mode (ion-exchange/reversed phase) Oasis MAX, Oasis WAX (strong and weak anion-exchange) Oasis MCX, Oasis WCX (strong and weak cation-exchange) 2007 Waters Corporation 9 OutlineOutline Introduction Why Sample Prep ConsiderationsoChoices of tools Why SPEoPre-Treatment Strategies Traditional approaches Modern approaches oMixed ModeoReverse phase Summary Appendix 2007 Waters Corporation 10 SPE StrategiesSPE #1 Retention, cleanup, # #3 Dispersion 2007 Waters Corporation 111.

5 Load2. wash3. is loaded onto SPE sorbent Analyte(s) of interest are retained on interferences are washed off are eluted from sorbentSPE Strategy 1 SPE Strategy 1 RetentionRetention--CleanupCleanup--Elut ionElution 2007 Waters Corporation 12 SPE Strategy 2 SPE Strategy 2 PassPass--Through CleanupThrough is passed through sorbent and collected no Sample interferences are retained on sorbentpass through 2007 Waters Corporation 13 SPE Strategy 3 SPE Strategy 3 Dispersion CleanupDispersion Cleanup Bulk sorbent is added to Sample with agitation Sample is filtered or centrifuged Supernatant is collected for

6 AnalysisThis is similar to pass-through cleanup, but less effective- Dispersion SPE is a one stage (one theoretical plate) cleanup- Pass-through SPE is a multi-stage cleanup 2007 Waters Corporation 14 OutlineOutline Introduction Why Sample Prep ConsiderationsoChoices of tools Why SPEoPre-Treatment Strategies Traditional approaches Modern approaches oMixed ModeoReverse phase Summary Appendix 2007 Waters Corporation 15 IonIon--Exchange and MixedExchange and Mixed--ModeMode Many compounds of environmental interest are weak acids ( dinoseb) or weak bases (i. e. aniline).

7 Weak acids can be ionized at high pH weak bases can be ionized at low pH Some compounds are strong acids ( PFOA) or strong bases ( chlorhexidine) that are ionic except at extreme pH values A few of these compounds are quaternary amines ( paraquat), ionic at all pH Ionizable Compounds 2007 Waters Corporation 16 Why MixedWhy Mixed--Mode?Mode? Mixed-Mode SPE extends pH range for good retention of acids or bases Retention can be by reversed-phase, ion-exchange or both Chose retention mode by adjusting pH ion-exchange allows for good retention in strong solventoacids can be retained by anion-exchange while bases/neutrals are washed off with strong solventobases can be retained on cation-exchange while acids/neutrals are washed off with strong solvent For environmental Analysis .

8 Mixed-mode SPE allows simultaneous retention of acids and bases 2007 Waters Corporation 17 OasisOasis Family of MixedFamily of Mixed--Mode Mode Sorbents:Sorbents:ReversedReversed--Phas e Retention and Ion ExchangePhase Retention and Ion Exchange 2007 Waters Corporation 18 Oasis MixedOasis Mixed--Mode Sorbents Mode Sorbents PFOS, PFOA (perfluoroacids and related compounds) Oasis WAX Acidic Herbicides Oasis MAX Quats Oasis WCX Pharmaceuticals/pesticides (organic bases) Oasis MCXS trategies for Isolation and Enrichment of Individual Compounds or Compound ClassesOasis 2x4 method 2007 Waters Corporation 19 IntroductionIntroduction Perfluorinated compounds (PFCs)

9 Such as perfluorooctanesulfonate and perfluorooctanoic acid are persistent organic pollutants (POPs) PFCs have been identified in environmental samples worldwide PFOS can be detected at low PPT levels in most humans PFOS commonly found in arctic fauna There is need for reliable analytical methods for PFCs in food, drinking Water , tissue, plasma and blood In this presentation we will discuss Sample Preparation for UPLC-MS determination of PFCs in Water and tissue samples 2007 Waters Corporation 20 UPLCUPLC--MSMS--MS SystemMS System ACQUITY Ultra Performance LC Using m particles, and at elevated pressures up to 15.

10 000 psi Shorter Analysis Time Higher Resolution Broad selectivity options Quattro Premier XE Fast acquisition rates Sensitive detection Oasis sorbents Cleaner samples 2007 Waters Corporation 21 GoalsGoals Develop an Acquity UPLCTM separation based on a recently published method* Adapt or modify the SPE protocol for UPLC River Water Sample Chicken Liver tissue Sample Lower the quantification limits to under 1 ppb in Chicken Liver tissue, and Low ppt level in River Water Sample *S. Taniyasu et. Chrom. A., 1093 (2005) pp89-97 2007 Waters Corporation 22 Structures of PFOS and PFOAS tructures of PFOS and PFOAF3 COOHFFFFFFFFFFFF perfluorooctanoic acidPFOApKa ~ 1perfluorooctanesulfonatePFOSpKa<<1 FFFFFFFFFFFFSOOO-F3 CFFPFOA and PFOS are Persistent Organic Pollutantsof high interest worldwide.