Over view What is ion chromatography? Why this techniqu is useful?
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Transcript of Over view What is ion chromatography? Why this techniqu is useful?
Ion ChromatographyIon Chromatography
1035510355
Over view
• What is ion chromatography?
• Why this techniqu is useful?
Ion chromatography- definition of terms• Ion exchange- involves exchange of one type of ion in a compound for another. exchange of K+, Ca 2+ and Fe 3+ with Na + in water.• Ion exchange chromatography- involves sequential exchange and elution of ions from a column. Retention is based on attraction between solute ions and charge boundary on the stationary phase.• Ion chromatography- same as ion exchange chromatography except that it includes a provision for removing and detecting (electrochemically) the ions in the eluting agent.
DefinitionsDefinitions
Ion Chromatography is a liquid
chromatographic technique, with
which ionic and strongly polar species
can be separated and detected.
IonIon ChromatographyChromatography System ConfigurationSystem Configuration
EluentEluentReservoirReservoir
PumpPump
Guard ColumnGuard Column
Analytical ColumnAnalytical Column
Suppressor Suppressor DeviceDevice
ConductivityConductivityCellCell
ChromatographyChromatographyWorkstationWorkstation
EluentEluentDeliveryDelivery
AnalyticalAnalyticalSeparationSeparation
DetectionDetection
Data Data Acquisition Acquisition
and and Instrument Instrument
ControlControl
SampleSampleInjectionInjection
11811-0211811-02
Type of Ion Chromatography
• Ion Exchange Chromatography
• Ion Exclusion Chromatography
• Ion Pair (ion Retardation) Chromatography
• Alternative Technique
Advantages of IonAdvantages of Ion ChromatographyChromatography
SpeedSpeed
- Complete anion and cation profiles in about 10 minutes- Complete anion and cation profiles in about 10 minutes
SensitivitySensitivity
-- Analyses in the lowest ppb-range without pre-concentrationAnalyses in the lowest ppb-range without pre-concentration- Analyses in the lowest ppt-range after pre-concentration- Analyses in the lowest ppt-range after pre-concentration- Limiting factor: contaminations by ubiquitous ions such as chloride - Limiting factor: contaminations by ubiquitous ions such as chloride
and sodium and sodium
SelectivitySelectivity
- Huge variety of stationary phases- Huge variety of stationary phases- Specific detection (suppression, UV, fluorescence, MS, ICP)- Specific detection (suppression, UV, fluorescence, MS, ICP)
Advantages of Ion Chromatography (cont.)Advantages of Ion Chromatography (cont.)
SimultaneitySimultaneity
- Simultaneous analysis of many sample components- Simultaneous analysis of many sample components (Contrary: AAS, Photometry, Titration, etc.) (Contrary: AAS, Photometry, Titration, etc.) - - Limiting factor: extreme concentration differences between the sample Limiting factor: extreme concentration differences between the sample components (Example: Semiconductor grade chemicals) components (Example: Semiconductor grade chemicals)
CostsCosts
- Contract laboratories offer anion and cation profiles with IC for US$ 15- Contract laboratories offer anion and cation profiles with IC for US$ 15- Price drop with system hardware as in all hightech areas- Price drop with system hardware as in all hightech areas
RobustnessRobustness
- pH and solvent compatible separators allow a variety of applications- pH and solvent compatible separators allow a variety of applications- Analysis of complex matrices such as waste water, foods, body fluids, etc.- Analysis of complex matrices such as waste water, foods, body fluids, etc.
History
• Aristol experiment(384-322 B.C)• Philasopheres(1561-1626)• Natural Zeolites in soil(1850)• Teoritical research(1876)• First commerical purposes(1896)• First synthetic compound(1903)• First truly successful use(1905)• Synthesise of organic compound(1935) • Use of small particles(1946)
Advantages of organic polymer
• High capasity
• Low sensitivity to temperature and PH
• Provided a back bone for various tyoe
of exchange groups
Making a cation Exchange Resin
Ion exchangers
• Three main classes• Resins
(polystyrene resins; used for molecules with Mr <500)
• Gels (cellulose and dextran; used for large molecules like proteins and nucleic acids)
• Inorganic exchangers (hydrous oxides of Zr,Ti,Sn and W; used for separations under harsh conditions (high temperature, high radiation levels, strongly basic solutions and powerful oxidizing agents)
Resin beads
Exchange functional groups
Cation Exchangers Anion Exchangers
strong -SO3H -N(CH3)3,Cl
-COOH -N(CH3)2CH2OH,Cl
-CH2 SO3H
-OH -NR2H,Cl
-SH -NRH2,Cl
weak -HPO2 H -NH3,Cl
A Lable of a Resin
Sulfonic acid,Na
Mesh:20-50
8X
4.4 meq/g
+
Lable information
Cross-linking Porosity Moisture holding capasity
2X High 85-95
4X IM.High 58-65
8X Medium 44-48
12X IM.Low 40-44
16X Low 37-41
Structure of Sodalite
Different types of ion exchange resins
• Polymeric porous particles
(formed from co-polymerisation of styrene-divinylbenzene)
• Pellicular and superficially porous particles
(formed by coating the ion exchange resin on to an
impervious inert core)
• Totally microporous particles with bonded phases
Pellicular Anion Exchange Bead (Latex)Pellicular Anion Exchange Bead (Latex)
SOSO--33
SOSO--33
SOSO--33
SOSO--33
SOSO--33
SOSO--33
SOSO--33
0.1 0.1 m Diameterm Diameter CoreCoreIon ExchangeIon Exchange
SurfaceSurface
RR33NN++
RR33NN++
NN++RR33
NN++RR33
NN++RR33
RR33NN++
RR33NN++
NN++RR33
NN++RR33
RR33NN++
RR33NN++
NN++RR33
NN++RR33
RR33NN++
RR33NN++
NN++RR33
NN++RR33
31833183--0202
Micro AnionMicro AnionExchange LatexExchange Latex
Sulfonated CationSulfonated CationExchange LatexExchange Latex
MicroporousMicroporous Polymeric PolymericSubstrateSubstrate8.5 mm8.5 mm
55% x-Link55% x-Link
200 200 nmnm
Latex CoatedLatex Coated Pellicular Cation Pellicular Cation Exchangers Exchangers
5606-025606-02
Classification of ion exchangers
• Classified :– by the charge on the stationary phase as:
• anion exchangers-contains positively charged groups• cation exchangers-contains negatively charged groups
– as strongly or weakly acidic or basic:
• strongly acidic cation exchangers eg RSO3-
• weakly acidic cation exchangers e.g RCO2-
• strongly basic anion exchangers e.g RNR’3+
• weakly basic anion exchangers e.g RNR2’H+
Example:
Selectivity and retention in ion exchange analysis
• These are affected by the size and charge of the solvated sample ion.
• Ion exchangers bind strongly to ions with higher charges, lower hydrated radii and higher polarizability
Thus order of selectivity is generally:
Pu 4+ >> La 3+ > Ce 3+ > Pr 3+ > Eu 3+ > Y 3+ > Sc 3+ > Al 3+ >> Ba 2+ > Pb 2+ > Sr 2+ > Ca 2+ > Ni 2 + > Cd 2 + > Cu 2+ > Co 2+ > Zn 2+ > Mg 2+ > UO2 2+ >> Ti + > Ag + > Rb + > K + > NH4 + > Na + > H + > Li +
Retention Determining Parameters (II)Retention Determining Parameters (II)
0 10 20 30 Minutes0
4
µS
F-
Cl-
NO2-
Br-
NO3-
PO43-
SO42-
I-SCN-
S2O32-
0 2 4 6 Minutes 10 0
4
µS
F- Cl-
NO2-
Br-
NO3-
PO43-
SO42-
Monovalent Anions Multivalent Anions
An exception to the rule?
00 1010 2020 3030 MinutesMinutes0
4
µS
F-
Cl-
NO2-
Br-
NO3-
PO43-
SO42-
I-SCN-
S2O32-
S
O
OO
O
2-
S
S
OO
O
2-
Retention Determining Parameters (III)Retention Determining Parameters (III)
Selectivity and retention in ion exchange analysis
• The pH of the mobile phase
• The total concentration and type of ionic species in the mobile phase
• Addition of organic solvents to the eluant
• The column temperature
PH of the mobile phase
Concentration
Ion Exchange Kinetics
• There are 5 main steps:• 1)agiated• 2)passage from the outer
solution to the bead• 3)actual exchange• 4)migration • 5)exit to the mobile
phase
Donnan equilibrium
• Refers to the equilibrium between ions in solution and ions inside the resin. This is the basis of ion-exclusion chromatography.
• For an anion-exchange resin, R+, in its Cl- form, immersed in a solution of KCl:
[K+]i [Cl-]i = [K+]o[Cl-]o --------(1) where i and o denote inside and outside the resin respectively.
• Inside the resin,
[R+]i + [K+]i = [Cl-]i -------(2)• Since from charge balance :
[K+]o = [Cl-]o
• considerations, equation (1) becomes :
[K+]i([R+]i + [K+]i ) =[K+]o2 ------------(3)
• Thus
[K+]o > [K+]i
Porous particlate andMicro porous membrane
FASTCHROM standard module and end plates
Applications of Ion exchange
• In water purification.– Deionised water is made by passing water through a anion-
exchange in it OH- form and a cation-exchange resin in its H+ form.
– Thus Cu(NO3)2 can be removed from water by the following reactions
• Cu 2+ H+ ion exchange 2H+ H2O• 2NO3- OH- ion exchange 2OH-}
• In water softeners– Cation exchange is used to remove Ca 2+ and Mg 2+ from
hard water• In converting one salt to another.• In pre-concentrating trace components of a mixture
– Cation-exchange resins are used to concentrate trace metals..
Ion chromatography
• This is the high performance version of IEC.• Common examples are:
– Suppressed cation chromatography and– Suppressed anion chromatography
• The key feature of IC is the presence of– an anion or cation separator column– a membrane ion suppressor– a detector
• The separator column separates the solutes while the suppressor replaces unwanted ions in the eluent with nonionic species
The Instrument
• COST: $40,000
Operation Principles
Eluent from the gradient pump enters the rheodyne injection valve port inside the enclosure
From the injection valve, eluent and sample flow through the guard column, the analytical column, the suppressor and finally through the detector cell.
The IC Schematic
• Pump, Column ($800), Guard ($200)• Air Pump for sample injection
Schematic of a Loop InjectorSchematic of a Loop Injector
11
22
33
44
55
6688
77
EluentEluent
WasteWaste
SeparatorSeparator
SampleSample
Injection valveInjection valve
Sample loopSample loop
Ion Chrom. for analysis of rain
• If inject sample with nitrate ion, nitrate replaced bicarbonate, but more bicarbonate moves in and kicks off nitrate
• Process continues as moves through column (ions go on and off beads)
• Sulfate in sample as well. Harder for bicarbonate to knock off.
• Conclude: Nitrate exits before Sulfate
Ion Chrom.
• See Peaks (Rain has nitrate, sulfate, some chloride)
IC Report
14209
EluentsEluents(NaOH, H(NaOH, H22SOSO44))
ChromatogramChromatogram
PumpPump
SuppressorSuppressor
ColumnColumn
InjectorInjector
Conductivity CellConductivity Cell
What is an IC?What is an IC?
RegenerantRegenerant
(H(H22SOSO44, TBAOH), TBAOH)
WasteWaste
Separation of Common Anions on the IonPacSeparation of Common Anions on the IonPac AS14 AS14
Column:Column: IonPac AG14, AS14 IonPac AG14, AS14Eluent:Eluent: 4.8 mM Sodium carbonate4.8 mM Sodium carbonate
0.6 mM Sodium bicarbonate0.6 mM Sodium bicarbonateFlow Rate: Flow Rate: 1.5 mL/min1.5 mL/minInj. Volume:Inj. Volume: 10 10 LLDetection:Detection: Suppressed conductivity, ASRS, Suppressed conductivity, ASRS,
AutoSuppressionAutoSuppression recycle mode recycle modePeaks:Peaks: 1.1. FluorideFluoride 5 5 mg/Lmg/L
2.2. ChlorideChloride 10103.3. NitriteNitrite 15154.4. BromideBromide 25255.5. NitrateNitrate 25256.6. PhosphatePhosphate 40407.7. SulfateSulfate 3030
1172411724
00
10 10
00 11 22 33 44 55 66 77 88 99MinutesMinutes
1122
33 44 55
66
77
Suppression:Suppression:
Reducing the background conductance due to the eluent to aReducing the background conductance due to the eluent to alow level while enhancing the conductance of the analyte.low level while enhancing the conductance of the analyte.
8140-018140-01
Small et al. PublishSmall et al. Publish1st IC Paper1st IC PaperPacked BedPacked BedSuppressionSuppression
CommercializedCommercialized
Fiber SuppressionFiber SuppressionCommercializedCommercialized
MicroMembraneMicroMembrane
SuppressorsSuppressorsIntroducedIntroduced
AutoRegenAutoRegen
IntroducedIntroduced
SRSSRS®® -I -IAutoSuppressionAutoSuppression®®
IntroducedIntroduced
2-2-mmmmMicroMembraneMicroMembrane
SuppressorsSuppressorsIntroducedIntroduced
SRS-IISRS-IIIntroducedIntroduced
19811981 19851985 19871987 19911991 19921992 1997199719751975
SRS-ULTRASRS-ULTRASuppressorsSuppressorsIntroducedIntroduced
19981998
Suppression Time LineSuppression Time Line1975 - 19981975 - 1998
11136-0211136-02
11309-0111309-01
The Role of Chemical SuppressionThe Role of Chemical Suppression
EluentEluent(NaOH)(NaOH)
Sample FSample F --, CI, CI --, SO, SO442-2-
AnalyticalAnalyticalColumnColumn(Anion(Anion
Exchanger )Exchanger )
AnionAnionSuppressorSuppressor
(Cation(CationExchanger)Exchanger)
HF, HCI, HHF, HCI, H22SOSO44in Hin H22OO
NaF, NaCI,NaF, NaCI,NaNa22SOSO44 in inNaOHNaOH
WasteWaste
H+H+
Without SuppressionWithout Suppression
Counter IonsCounter Ions
SS
F-F-
SOSO442-2-
CICI--
F-F- SOSO442-2-
TimeTime
SS
TimeTime
With Chemical SuppressionWith Chemical Suppression
CICI--
NaNa++
What are Suppressors in Ion Chromatography What are Suppressors in Ion Chromatography Good For ?Good For ?
• To reduce background conductance caused by the eluent and, therefore, to reduce noise
• To convert analyte ions into a more strongly conducting form
• To improve sensitivity • To improve the dynamic range• To be able to use high capacity separators with
higher ionic strength eluents• To be able to use gradient elution techniques in
combination with conductivity detection
Advantages of Continuous SuppressionAdvantages of Continuous Suppression
• Improved stability of the system
• Very little drift and low noise
• High suppression capacity
• No external regeneremts necessary
• Simple operation – no extra programming
• Simplified hardware – no extra valves
• Flexible method development
Equivalent Conductances of Common IonsEquivalent Conductances of Common Ions
AnionsAnions CationsCations
IonIon 00((µµS cmS cm 11)) IonIon 00((µµ S cmS cm 11))
OHOH 198.6198.6 HH++ 349.8349.8
CICI 76.476.4 NaNa++ 50.150.1
SOSO4422 80.080.0 KK++ 73.573.5
NONO33 71.571.5
MSAMSA 48.848.8
**MSAMSA--: Methanesulfonate: Methanesulfonate
Suppression replaces eluent counterions with more highly conducting HSuppression replaces eluent counterions with more highly conducting H++ or orOHOH-- ions ions
Self Regenerating Suppressor SchematicSelf Regenerating Suppressor Schematic(Ion Exchange Membrane - Continuous Regeneration)(Ion Exchange Membrane - Continuous Regeneration)
12442-0112442-01
Na+OH-
(Eluent)
Na+Cl-(Sample)
HOH(Eluent)
H+Cl-(Sample)
ConductivityDetector
Cation Exchange Membrane in HCation Exchange Membrane in H++ form form
Waste
Regenerating ElectrodeRegenerating Electrode
Eluent RecycleEluent Recycle
H2O
H+Na+
Na+
H+ O2
-e
+
DetectorDetectorCellCell
WasteWaste
EluentEluentSRSSRS
RecycledRecycledto SRSto SRS
1431143155
Eluents: Eluents: ASRSASRS —— Hydroxide, carbonate/bicarbonate Hydroxide, carbonate/bicarbonate
CSRSCSRS —— Methanesulfonic Methanesulfonic acid (MSA), sulfuric acid acid (MSA), sulfuric acid
--
++
SRSSRS AutoSuppression AutoSuppression
Recycle ModeRecycle Mode
DetectorDetectorCellCell
WasteWaste
EluentEluentSRSSRS
1431714317
Eluents: Eluents: ASRSASRS —— Hydroxide, carbonate/bicarbonate Hydroxide, carbonate/bicarbonate
CSRSCSRS —— Methanesulfonic Methanesulfonic acid (MSA), sulfuric acid acid (MSA), sulfuric acid
--
++
WasteWaste
H2SO4 or TBAOH(P)
SRSSRS Chemical Regeneration Mode Chemical Regeneration Mode
AutoSuppression Using Anion SRSAutoSuppression Using Anion SRS
8482-8482-BB
AnodeWaste/Vent
H2O, O2
Na+X- in Na+ OH- Eluent
Na+OH-
Waste/VentCathode
Na+ OH- , H2
H2 + OH-
H2O
H2O
CationExchangeMembrane
CationExchangeMembrane
To Detector
H+ + O2
H2O
H2O
H+
H2O
H+X-H+ + X-
H+ + OH-
H+X- in H2O
AutoSuppression Using the Cation SRSAutoSuppression Using the Cation SRS
8483-018483-01
AnodeWaste/Vent
H+MSA-, O2
M+MSA- in H+MSA- EluentWaste/Vent
Cathode
H2O , H2
OH-
H2 + OH-
H2O
H2O
AnionExchangeMembrane
AnionExchangeMembrane
To Detector
H+ + O2
H2O
H2O
H+
H2O
M+OH-H+ + X-
H+ + OH-
M+OH- in H2O
H+MSA- = Methanesulfonic Acid
MSA-
Single ion chromatography
• Used when– Exchange capacity of the separator column is low– Dilute eluents are employed– Ion suppression is unnecessary
• Examples of resins with low exchange capacities are:– Na + or K + salts of benzoic, p-hydroxybenzoate and
phthalate.
Gradient elution
• Ionic gradient elution is similar to temperature or solvent gradient.
• Changing the ionic strength or pH of the eluent improves separation considerably.
• For example, a mixture of Na+, Li+, Ca 2+ and Fe 3+ can be separated by using elution with increasing concentrations of HCl.
• The order of elution being Li +, Na + > Ca 2+ > Fe 3+
Gradiant separation of a synthetic mixture of 36 anions in 24 min.
Advantages of UsingAdvantages of Using Eluent Generators in Ion Chromatography Eluent Generators in Ion Chromatography
Requires only deionized water as the carrierRequires only deionized water as the carrier
Generates high-purity, contaminant free acidGenerates high-purity, contaminant free acidand base eluents on-lineand base eluents on-line
Eluent concentration controlled electricallyEluent concentration controlled electricallywith minimal delaywith minimal delay
Improved retention time reproducibilityImproved retention time reproducibility
Minimize pump maintenanceMinimize pump maintenance
1429714297
Gradiant Elution
Detector in Chromatography
• Electrochemical Detector - Conductivity Detector - Amperometric Detector
- Pulsed Amperometric Detector
• Spectroscopy Detector - UV/Vis - Fluorescence - PDA
Detection
• Conductivity detectors are the most popular• In addition, when analytes have
– Ultraviolet absorbance– Fluorescence or– Radioactivity other forms of detection are employed.
• Many ion exchange methods require the presence of complexing agents (EDTA, citrate) and various electrolytes to achieve good resolution. Therefore, conductivity detectors can not be used without modifying the process (eg by suppressing some of the ions).
• Indirect detection is possible when benzoate or phthalate eluents are used.
The Altec model 1000 electrochemical regenerated ion suppression system
and Sample preconcentrator
IC conductivity Detectors
• Detectors: Based on ability of water to conduct electricity
• Suppressor membrane destroys bicarbonate only
• Conductivity of ions can be measured to very low levels
Electrochemical palsed amperometric cell assembly
5031-025031-02
Triple Potential Sequence Used inTriple Potential Sequence Used inPulsed AmperometryPulsed Amperometry
PotentialPotential
IntegrationIntegrationDelayDelay
E2E2
E1E1E3E3
t3t3
t2t2
TimeTime
Column size PH range capasity Particle size Type of packing mm µm
Vydac 250x4.6 2-6 100 20 spherical silica with IC bonded quaternary groups
INtraction 50x3.2 0-14 100 10 Neutral hydrophilic Ion100 narymacroporous resin with covalentlyi bond ammonium groups
Hamilton 150x4.1 1-13 200 10 Highly crosslinked -X100 covalentlyi bond ammonium groups
Bio-GelTSX 50x4.6 1-12 30 10 Polymetacrilat gel coated with Anion PW quaternaryammonium groups
Waters ic 50X4.6 1-12 30 10 Same Pak A
One chromatogram with 5 detector
Ion-pair chromatography
• Uses reverse phase HPLC in place of an ion exchange column
• A hydrophobic ion pairing reagent containing a counter-ion, with an opposite charge to the ion to be determined is added to the mobile phase.
• This counter ion combines with the ions of the eluent to form ion pairs in the stationary phase.
• For example, Fe(phen)3 2+ forms [Fe(phen)3
2+ ] [anion] ion pair.
• Retention of analytes depend on– Alkyl chain length of the counter-ion– Concentration of the ion pairing reagent– Solvent strength– Combination with ion suppressor
Ion Exchange ChromatographyIon Exchange Chromatography
Mechanism of RetentionMechanism of Retention
11229
StationaryPhase
NR3+
S
S
MobilePhase
S
Mechanism of Anion Ion-PairingMechanism of Anion Ion-Pairing
1280712807
Eluent: TBAOH/ACN/HEluent: TBAOH/ACN/H22OOSample: Anions (A)Sample: Anions (A)
HydrophilicHydrophilicEnvironmentEnvironment
HydrophobicHydrophobicEnvironmentEnvironment
ACNACN
TBATBA++ __AA
ACNACN
TBATBA++ __AA
ACNACN
TBATBA++ __AA
TBATBA++ __AA
NeutralNeutralMacroporousMacroporous
Resin (PS/DVB)Resin (PS/DVB)
TBATBA++ OH OH __
ACN: AcetonitrileACN: AcetonitrileTBAOH: Tetrabutylammonium hydroxideTBAOH: Tetrabutylammonium hydroxide
((TBATBA++ __A)A)
TBATBA++ OH OH __
HH22OO
ACNACN
((TBATBA++ __A)A)
HH22OO
ACNACN
Separation of Aliphatic Sulfonic AcidsSeparation of Aliphatic Sulfonic AcidsUsing Ion-Pairing with Suppressed ConductivityUsing Ion-Pairing with Suppressed Conductivity
11140-0111140-01
Column:Column: IonPac NS1 (10 IonPac NS1 (10 탆탆))Eluent:Eluent: 2 mM Tetrabutylammonium hydroxide,2 mM Tetrabutylammonium hydroxide,
24% to 48% Acetonitrile in 10 min24% to 48% Acetonitrile in 10 minFlow Rate:Flow Rate: 1.0 mL/min1.0 mL/minInj.Volume:Inj.Volume: 50 50 킠킠Detection:Detection: Suppressed conductivitySuppressed conductivity
ASRS AutoSuppressionASRS AutoSuppression,,external water modeexternal water modeRegenerant:Regenerant: 10 mN Sulfuric acid10 mN Sulfuric acidPeaks:Peaks: (as the acid forms)(as the acid forms)
1. Methanesulfonic acid1. Methanesulfonic acid 5.0 mg/L (ppm)5.0 mg/L (ppm)2. 1-Propanesulfonic acid2. 1-Propanesulfonic acid 8.68.63. 1-Butanesulfonic acid3. 1-Butanesulfonic acid 8.78.74. 1-Hexanesulfonic acid4. 1-Hexanesulfonic acid 8.88.85. 1-Heptanesulfonic acid5. 1-Heptanesulfonic acid 8.98.96. 1-Octanesulfonic acid6. 1-Octanesulfonic acid 8.98.97. 1-Decanesulfonic acid7. 1-Decanesulfonic acid 9.19.1
11
66
66
22 33
00MinutesMinutes
121222 1414 161688
킪킪
0.00.0
44
44 55
77
8.08.0
1010
Schematic of Ion Exclusion MechanismSchematic of Ion Exclusion Mechanism
99639963
Mobile Phase
Donnan-Membrane
Stationary PhaseH220
H++Cl--
H220
H220
H220
SO33--H++
SO33--H++
SO33--H++
SO33--
H220
SO33--
H220
--
H++
(Eluent)
CH33COOHH++
Example for separation with regeneration
…THE …END…
…THE …END…