Ion

ChromatographyJORDAN SEDLOCK

DECEMBER 2, 2014

CHEM 310

What is Ion Chromatography

Ion chromatography (IC) is a form of liquid chromatography that describes efficient peak separation amongst ionic species.

Used to separate and quantify at trace levels:

Ions/ ionizable molecules

Low-molecular-mass acids and bases

Inorganic anions and cations

Applicable to:

Food analysis

Water quality treatment

Pharmaceuticals

Types of Ion

Chromatography

Ion-exchange Chromatography (IEC)

Ion-exclusion Chromatography (IEC)

Ion-pair Chromatography (IPC)

Ion-suppression Chromatography (ISC)

Ion-exchange

Chromatography (IEC)

Separates inorganic anions and cations

Based on affinity of analyte and charged, ionic R-

groups on stationary phase

Anion & Cation exchangers:

Anion: contain + charged R- groups to attract anions

Cation: contains – charged R- groups to attract cations

Stationary phase composition:

Resins (small molecules)

Gels (macromolecules)

Inorganic exchangers (extreme chemical conditions)

Ion-exclusion

Chromatography (IEC)

Separates weak acids/

bases and hydrophilic

biomolecules (e.g.,

carbohydrates)

Molecular species rather

than ions but can be used

to separate analytes

based on size, shape, and

charge

Functions by Donnan

Exclusion mechanism

http://www.chromacademy.com/lms/sco111/theory_of_hplc_ion-chromatography.pdf

Ion-pair Chromatography

(IPC)

Separates polar and ionic compounds with reversed

phase HPLC column rather than IEC column

Relies heavily on composition of mobile phase for

separation

Organic solvent & ion-pair reagent

Large ionic molecule: w/ charge opposite that of analyte &

hydrophobic region to interact with st. phase (PS/DVB)

Ion-pair Chromatography

(IPC)

To separate cations:

anionic surfactant added

to mobile phase

Lodges into st. phase

ion exchanger

Analyte cations attracted

to surfactant anions

Ion-suppression

Chromatography (ISC)

Separates weak, polar acids and bases

Involves removal of unwanted analyte prior to detection

Anion suppression:

Anions separated using anion separator column and strong base

(eluent)

Passed through suppressor where strong base water

Cation suppression:

Cations separated using cation separator column and strong acid

(eluent)

Passed through suppressor where strong acid water

Ion-suppression Chromatography

(ISC)

Sample Preparation

Dependent upon sample composition

Matrix dominated samples:

Matrix elimination IC

SPE

Water samples:

Filtering alone or dilution (to detectable range) and then

filtering

Solid samples:

Aqueous extraction

Acid digestion

Combustion

Analysis Time

Range of 6 to 20 minutes based on research

6.5 minutes: anionic/ cationic nutrients in waste water

samples

7 minutes: arsenic in cereal based foods

10 minutes: anions in lake water samples

12 minutes: transition metals in sea water samples

18 minutes: weak acid determination (food chemistry)

20 minutes: separation of proteins from complex

biological mixtures

How Much Does it Cost?

Thermo Scientific HPIC

system designed to

maximize resolution,

speed, and sensitivity

Approximately $35,000

http://www.thermoscientific.com/content/dam/tfs/ATG/CMD/CMD%

20Product%20Images/Chromatography/Ion%20Chromatography/I

C%20and%20RFIC%20Accessories/ICS-5000-

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Operational Theory of IC

Contains: eluent, pump, injection valve, column,

suppressor, detector, data collection system

http://www.shodex.com/assets/images/en-illust/i0055a.gif

Application: Perchlorate

Determination (2013)

Perchlorate: common ingredient in rocket fuel

Causes interference of iodide uptake and proper

functions of thyroid gland serious human health

threat

Contaminating drinking water

Ion exchange chromatography with anion exchange

column

Complete separation of all analytes in sample

completed in 7 minutes

Valid results in relatively short time with little sample

preparation needed

Advantages and Limitations

Advantages

Sample prep is not

extensive (no need to

correct for matrix effects)

Shorter analysis time for

simpler samples (generally

10-12 minutes)

High selectivity with solute

specific detectors

Detect/analyze multiple

sample components

simultaneously

Small sample volume

Sensitivity on μg/L level

Limitations

Soil, sediment, geological

sample prep is more

extensive

Longer analysis time for

more complex samples

Can’t select specific

compounds for high speed

analysis

Sometimes overlap can

occur in chromatogram

when compounds have

similar separation

characteristics

ReferencesIon chromatography. Http://ionchromatography.Co.Uk/2011/12/25/the-history-of-ion-exchange-chromatography/ (accessed oct 15, 2014).

Chromacademy. Http://www.Chromacademy.Com/lms/sco111/theory_of_hplc_ion-chromatography.Pdf (accessed oct 15, 2014).

Haddad, p. R.; Doble, P.; & Macka, M. Developments in sample preparation and separation techniques for the determination of inorganic ions by ion chromatography and capillary electrophoresis. Journ. Of chrom. A. 1999, 856, 145-177.

Chromedia analytical sciences. Http://www.Chromedia.Org/chromedia?Waxtrapp=lcejigshqnoxmolieccbcehhhcc&subnav=xododdshqnoxmolieccbcehhhccfc (accessed oct 15, 2014).

Harris, d. C. Chromatograpic methods and capillary electrophoresis. In quantitative chemical analysis; W. H. Freeman and company: new york; 2010; 635-646.

Milagres, m. P.; Brandao, S. C. C.; Malgalhaes, M. A.; Minim, V. P. R.; & Minim, L. A. Development and validation of high-perfomance liquid chromatography-ion exclusion method for detection of lactic acid in milk. Food chem. 2012, 135, 1078-1082.

Dionex. Http://www.Dionex.Com/en-us/webdocs/4696-TN12_LPN0705-01.Pdf (accessed oct 16, 2014).

Koch, w. F. Sample preparation in ion chromatography. Journ. Of res. 1979, 84, 241-245.

Jackson, p. E. Ion chromatography in environmental analysis. In encyclopedia of analytical chemistry; meyers, R. A.; Ed.; John wiley & sons ltd: chichester; 2000; 2779-2801.

Karmarkar, s. V. Analysis of wasterwater for anionic and cationic nutrients by ion chromatography in a single run with sequential flow injection analysis. Journ. Of chrom. A. 1999, 850, 303-309.

Llorente-mirandes, t.; Calderon, J.; Centrich, F.; Rubio, R.; & Lopez-sanchez, J. F. A need for determination of arsenic species at low levels in cereal-based food and infant cereals. Validation of a method by IC-ICPMS. Food chem. 2014, 147, 377-385.

Gajdoski, m. S.; Kovac, S.; Malatesti, N.; Muller, E.; & Josic, D. Ion-exchange sample displacement chromatography as a method for fast and simple isolation of low- and high-abundance proteins from complex biological mixtures. Food technol. Biotechnol. 2014, 52(1), 58-63.

Thermo scientific. Http://www.Thermoscientific.Com/en/product/dionex-ics-5000-capillary-hpic-system.Html (accessed oct 27, 2014).

Dionex. Principles and troubleshooting techniques in ion chromatography. Dionex corporation: 2002; document no. 034461.

Jackson, p. E.; Gokhale, S.; Streib, T.; Rohrer, J. S.; & Pohl, C. A. Improved method for the determination of trace perchlorate in ground and drinking waters by ion chromatography. Journ. Of chem. A. 2000, 888, 151-158.

Jiang, s.; Li, Y.; & Sun, B. Determination of trace level perchlorate in antarctic snow and ice by ion chromatography coupled with tandem mass spectrometry using an automated sample on-line preconcentration method. Chin. Chem. Lett. 2013, 24, 311-314.

Li, y.; Whitaker, J. S.; & Mccarty, C. L. Analysis of iodinated haloacetic acids in drinking water by reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry with large volume direct aqueous injection. Journ. Of chrom. A. 2012, 1245, 75-82.

Roehl, r.; Slingsby, R.; Avdolovic, N.; & Jackson, P. E. Applications of ion chromatography with electrospray mass spectrometric detection to the determination ofenvironmental contaminants in water. Journ. Of chrom. A. 2002, 956, 245-254.