- - 1 Dr. Shulamit Levin, Analytical Consulting, Medtechnica

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1 Ion xchange Chromatography Chromatographic rocess BA Mobile phase tationary hase A Dr. hulamit Levin Medtechnica B Distribution: K = C s/cm B A lution through the Column Chromatogram Ion xchange Theory Cation xchange vs Anion xchange Cation xchange Anion xchange Cation exchange columns have a negative charge to attract cations. Anion exchange columns have a positive charge to attract anions AML I I. IJCTI I XCHAG IID A I TH TATIAY HA 2. ADTI: DILACMT F CUT I CUT I UT 3. LUTI MBIL HA ADDITIV Dr. hulamit Levin, Analytical Consulting, Medtechnica

2 I XCHAG AI XCHAG K XY B Y X B X Y Analysis of Ions Ion Chromatography I (Mono, Di, Tri Valent) FUCTIAL CATI XCHAG AI CATI K M H A M H A H M rganic Acids henols Inorganic F Cl rganic Amines Inorganic Metals H 4 IMMBILIZD TH TATIAY HA Ions can be characterized as: organic or inorganic, anion or cation, mono or polyvalent. Ion xchange Theory trong vs. Weak xchange Materials Cation exchanger Anion exchanger 3 3 TG C H 3 WAK trong xchangers stay ionized as ph varies between 2 and 2. Weak exchangers can lose ionization as a functionof ph. Ion xchange Bonded Functionalities WAK TG Cation Anion C a Cl Carboxylic Acid 3 a ulfonic Acid H rimary, econdary or Tertiary Amine Cl Quaternary Amine Typical chemical functionalities used for commercial exchangers. 2 Dr. hulamit Levin, Analytical Consulting, Medtechnica

3 Conductivity and DA Detectors in eries Functional groups µ Detection: Direct Conductivity after uppression Detection: UV (DA) at 24 nm. Fluoride 2. Chloride 3. itrite 4. Bromide 5. itrate 6. hosphate 7. ulfate Column: luent: 0.03 AU 0.02 Flow rate: Injection vol.: Minutes ppm 2 ppm 6 ppm Waters ICak Anion H.2 mm odium Carbonate/.2 mm odium Bicarbonate.0 ml/min 50 µl CATI XCHAG AI XCHAG TY FUCTIAL FUCTIAL GU TY GU ulfonic acid 3 H Quaternary amine (CH 3 ) 3 H Carboxylic acid C H Quaternary amine (CH 3 ) 2 (th) hosphonic acid 3 H Tertiary amine H(CH 3 ) 2 H phosphinic acid H 2 H econdary amine H 2 (CH 3 ) 2 H henolic H rimary amine H 3 H Arsonic HAs 3 H elenonic e 3 H Columns Matrices ilicabased olymerbased ionexchangers Hydrous xide =MH =M H =MH =M H esin Ion xchange Theory acking upports ilicabased Capacity welling Mass Transfer ize eparation everse hase fficiency ph ange quilibration Literature Both resin and silica based ion exchangers have advantages and disadvantages which are summarized here. 3 Dr. hulamit Levin, Analytical Consulting, Medtechnica

4 I XCHAG AI TTI & LUTI TGTH F, H > Ac > H > HC >Cl H > C > Br > > I 3 3 A > A > A > > 2 I XCHAG Li > H > a > H 4 > K >b > Cs > Ag Be > Mn Transition metals Al Mg CATI TTI & LUTI TGTH MVALT DIVALT Zn > Co TIVALT > M >Ce > M > Ca transition metals >r roperties of Mobile phases Compatibility with the detection mode uppressed or onsuppressed. ature of the competing ion Concentration of the competing ion Mobile phase's ph Buffering capacity of the mobile phase Ability to complex the ionic sample components rganic modifiers Ion capacity The number of functional groups per unit weight of the stationary phase. A typical ionexchange capacity in IC is 0 00 mequiv/g. 4 Dr. hulamit Levin, Analytical Consulting, Medtechnica

5 LUTI D I AI XCHAG DITY F CHAG LUTI D I CATI XCHAG DITY F CHAG Ac H F Cl 3 2 K a Li Ag Zn Al TIM (MI.) TIM (MI.) IIZATI and TTI WAK ACID HA H A The quilibrium Constant k HAc H Ac K k 2 a = (H ) (Ac) (HAc) HB pka~ 45 At ph >45 the main species is A WAK BA H B (H ) = K a (HAc) (Ac) ph and pk a ph = pk a log (HAc) (Ac ) pka ~ 78 At ph < 78 the main species is BH A general understanding of ionization constants, ph, and pk a are useful in understanding ion exchange and buffer phenomena. 5 Dr. hulamit Levin, Analytical Consulting, Medtechnica

6 LUTI D I I XCHAG AI XCHAG CATI XCHAG Amino Acids Analysis In lasma Ion xchange with inhydrin detection TG ACID TG BA TIM (MI.) TIM (MI.) 6 Dr. hulamit Levin, Analytical Consulting, Medtechnica