3
How mixed sample
can be separated?
river bed
direction of flow
4
What is the difference?
Interaction difference
Strong
Weak
Classification of Chromatography
On the basis of Geometry (Planner, Colum)
Mode of Separation (Adsorption, Partition, Ion Exchange,
Size Exclusion, Affinity)
Nature of Stationary Phase(GLC,GSC, LSC & LLC)
Nature of Mobile Phase (Liquid chromatography, Gas
chromatography, SCF chromatography)
5
Advancement in Liquid Chromatography
Scientists Year Achievement
Tswett 1903 Introduction of liquid chromatography
N. A. Izmailov 1938 TLC
Martin & Synge1941 Liquid-Liquid Chromatography
Huber 1967 LLC with small particles
Horvath and Lipsky1966-67Instrumentation of HPLC
Wilmington 1971 First Book on HPLC
R.E. Majors 1972-78Small porous silica particles & modified
st.phases
Hjerten& Liao 1988 Polymer based monolithic column
Nakanishi & Soga1991 Silica based monolithic column
Knox & Grant 1991 Capillary electrochromatography
Currently HPLC is one of the most widely used technique for Analysis,
purification ,identification, quantification of mixtures of compounds
9
Componentsofamixtureareseparatedthroughacolumn
bytheirpartitioningbetweenstationaryphaseandmobile
phaseunderpressure
Accordingtodistributionorpartitioncoefficient(K
c)
X
m X
s
K
c=[X]
s/[X]
m
X
s=Concentrationofthecomponentinthestationaryphase
X
m=Concentrationofthecomponentinthemobilephase
Principle of HPLC
A
B
C
D
E Sample Mixture
Chromatogram
0 5 10 15 20
Time (minutes)
Abundance
A
B
C
D
E
Chromatograph
The HPLC Chromatogram
The time that a peak
appears (it’s retention
time) is diagnostic for a
given compound
The relative size of a
peak (area or height)
is proportional to the
relative abundance of
the compound in the
mixture
Mobile Phase Supply System
Individual reservoirs store the
mobile phase components until
they are mixed and used.
Solvent Features
A range of solvents available
High Purity
Degassed
HPLC Grade (filtered through 0.2 µm)
HPLC Pumps
Pneumatic Type (non reciprocating/constant pressure pumps)
Syringe Type (Mechanically driven)
Hydraulic Amplifier Pump
Reciprocating type (Electrically driven, most common)
minimum flow surges, Dual pistons
Pressure of 1,000-3,000 psi often required for 1-2 mL/min
80-90% separation require <1200 psi
16
Isocratic System
pump
injector
column
oven
detector
Simple system with 1 pump and
1 solvent reservoir.
If more than 1 solvent is used, solvents
are premixed.
data
processor
17
Low-pressure Gradient System
pump
injector
column
oven
detector
One pump used to
control 4 reservoirs;
mixing is done
before pump.
low pressure
gradient valve
data
processor
18
injector
column
oven
detector
pump
pump
High-pressure Gradient System
pump
mixer
data
processor
19
Elution Mode in HPLC
Isocratic elution mode
One mobile phase with a constant composition
Gradient elution mode
Multi mobile phases with changing composition
20
Isocratic Elution Mode
Long Time Analysis
Bad Separation
MeOH / H
2O = 6 / 4
MeOH / H
2O = 8 / 2
Injectors
Introduces the sample into the mobile phase
stream to be carried into the column.
Two major designs:
Manual Injectors
Automatic Injectors
23
Manual injector
Auto injector
Column-The Heart of HPLC
Guardcolumn
Protects the analytical
column
Particles
Interferences
Prolongs the life of the
analytical column
Analyticalcolumn
Performs the separation
Lenghth:10 -30 cm, i.d 3.9 or 4.6mm
A typical 15-cm long column with 4.6
mm id have 15,000 plates with 3 µm
particles, 9000 with 5 µm and 5000 for
10 µm.
A 25 cm long column may have
ca.50,000 plates
Column Composition
Solid Support -Backbone for bonded phases.
High-purity spherical silica (particles 10µm, 5µm or 3µm);
Microporus particles (pore size 60-100 Å)
Cross linked polymeric particles (polystyrene,
polymethacrylates)
Monolithic packing [(rod like structure of silica, bimodal pore
macropore(2 µm), mesopore (13nm)]
Bonded Phases -Functional groups firmly linked (chemically
bound) to the solid support.
Extremely stable
Reproducible 25
Chromatography Stationary Phases O O O
| | |
OSiOSiOSiOH
| | |
O O O
| | |
OSiOSiOSiOH
| | |
O O O
bulk (SiO
2)
xsurface
Silica Gel O O O
| | |
OSiOSiOSiOR
| | |
O O O
| | |
OSiOSiOSiOR
| | |
O O O
bulk (SiO
2)
xsurface
Derivatized Silica Gel
Where R = C
18H
37
hydrocarbon chain
(octadecylsilyl deriv.
silica or “C18”)
relatively polarsurface relatively nonpolarsurface
“normal phase” “reversed phase”
DMCS
Silination
27
Normal Phase Mode
Column : polar property
Solvent : non polar property
TheoreticalPlate Model of Column
Efficiency of a Column
Theoretical plate number (N)
N = 16 (t
R/w
b)
2
HETP = L/N
29
Normal Phase HPLC Columns
Silica gel type : general use
Cyano type : general use
Amino type : for sugar analysis
Diol type : for protein analysis
Silica gel
Si
Si
-Si-CH
2CH
2CH
2CN
-Si-CH
2CH
2CH
2NH
2
-Si-CH
2CH
2CH
2OCH(OH)-CH
2(OH)
Modified Si
30
What is the interaction?
Silica gel (polar)
Hydrogen bonding
Non-polar
Hydrogen bonding
If the sample has
-COOH : Carboxyl group
-NH
2 : Amino group
-OH : Hydroxyl group
Hydrogen bonding becomes strong.
If the sample has bulky group,
due to steric hindrance
Hydrogen bonding becomes weak.
32
Mobile phase solvents for
normal phase HPLC
Primary solvents (non-polar)
Hydrocarbons (Pentane, Hexane, Heptane, Octane)
Aromatic Hydrocarbons (Benzene, Toluene, Xylene)
Methylene chloride
Chloroform
Carbon tetrachloride
Secondary solvents
Methyl-t-butyl ether (MTBE), Diethyl ether, Tetrahydrofuran
(THF), Dioxane, Pyridine, Ethyl acetate, Acetonitrile, Acetone, 2-
propaol, ethanol, methanol
A primary solvent is used as mobile phase. Addition of
secondary solvents is to adjust retention time.
34
Reversed Phase HPLC Columns
C18 (ODS) type
C8 (octyl) type
C4 (butyl) type
Phenyl type
Cyano type
-Si-C
18
H
37
Si
Non-polar property
35
What is the interaction?
Hydrophobic
interaction
Non-polar
polar solvent
36
Hydrophobicity
If the sample has more
CH
3CH
2CH
2---: Carbon chain
: Aromatic group
If the sample has more
-COOH : Carboxyl group
-NH
2 : Amino group
-OH : Hydroxyl group
Hydrophobicity
is stronger.
Hydrophobicity
is weaker.
37
Mobile phase solvents for reversed
phase HPLC
Water (buffer) + Organic solvents
Methanol (MeOH), acetonitrile
(ACN) or THFare common organic
solvents for r.p HPLC.
38
Effect of stationary phase
C18 (ODS)
Strong
C8
sample
sample
sample
C4
Medium
Weak
Normal Phase vs. Reverse Phase HPLC
Skoog and Leary: Principals of Instrumental Analysis, 5
th
ed. Suanders, 1998
40
Column Temperature Control Devices
•Column temperature control devices are functioning to keep the
column temperature constant.
•The temperature fluctuation of column will influence retention
time reproducibility.
Important Features of Selected Detectors
Detectors Approx. limit of
detection
Features
UV/Vis.
10
-8
g mL
-1
(0.01ppm) high sensitivity, insensitive to
changes in temperature and flow rate,
suitable for gradient elution.
Fluorescence
10
-11
-10
-12
g mL
-1
(0.1 -1ppt)greater detection sensitivity,
insensitive to changes in temperature
and flow rate, suitable for gradient
elution.
RI
10
-5
-10
-6
g mL
-1
(10 -1ppm)universal, lack high sensitivity, not
suitable for gradient elution,
temperature and pressure sensitive
43
Sample Preparation for HPLC
Extraction
Liquid phase extraction
Solid phase extraction
Removal of insoluble material
Filtration
Centrifuge (Precipitation)
Control of concentration
Concentration
Dilution
Derivatizationfor detection
Data Interpretation in HPLC
Qualitative analysis
The retention times of unknown compounds are
compared with those of pure standards
Quantitative analysis
Integration of peak area
base
height
Area = Wb x height
2
Triangulation
Normalization
%Area = Area of peak x 100
Tolal Area
47
Separation of Sugars
Peak identification;
1
sucrose;
2
glucose;
3
fructose
Bio-Rad Aminex HPX-87K 300 ×7.8 mm column, mobile phase
was ultra pure H
2O at a flow rate of 0.6 mL/min , RI detector
Separation of Organic Acids
48
Peak identification;
1
tartaric acid;
2
ascorbic acid;
3
malic acid;
4
citric acid
Mobile phase consisted of 5 % methanol in 25 mM potassium dihydrogen
phosphate ; RP-C18 column (250 mm x 4.6mm; 5µ particle size), Detector
diode array detector (DAD)
Separation of Phenolic acids
49
Peak Identification: 1. Gallic acid 2. . Chlorogenic acid3.P-hydroxy-benzoic acid 4. Vanillic acid ,
5. p-coumaric acid 6. Ferulic acid
RP-C18 column (250 mm x 4.6mm, 5µ particle size); Mobile phase consisted of 40 % Trifluoroacetic
acid (0.3 %), 40 % Acetonitrile and 20 % Methanol , detected at 280 nm.
Mn(II)
Co(III)
Cu(II)
Cr(III) Mn(II) Fe(III) Co(III) Ni(II) Cu(II)
0 5 10 15
min.
MDC
Coupled column chromatographic
separation of metal complexes
0 2 4 6
8
Ion chromatography of F,
CH
3COO, Cl, NO
3 , Br in
suppressed conductivity mode
RP-HPLC of NO
3, Cl, Br, I
with UV detection
Lucy et al. J.Chromatogr. A
1000, 711, 2003
Bhanger, Khuhawar, Arain,
J. Sep. Sci., 25, 462, 2002
Minutes
New Trends in HPLC
FPLC-Fast Protein Liquid Chromatography
•Separation & purification of proteins and other polymeric complex mixtures
•Separation of macromolecules based on size, charge distribution (ion exchange),
hydrophobicity, reverse-phase or biorecognition (as with affinity chromatography)
•FPLC differs from HPLC in that the columns used for FPLC can only be used up to maximum
pressure of 3-4 MPa (435-580 psi).
•Columns used in FPLC are large [mm id] tubes that contain small [µ] particles or gel beads
LC-MS
•Powerful technique used for many applications which has very high sensitivity and
selectivity
•In particular used for pharmacokinetic, Proteomics/Metabolomics, Drug development
LC-MS-NMR
•A revolution in the separation science
•Power full platform for the analysis complex mixtures
•Determination of molecular weight and composition with in fmol/l concentration
•The exact mass, isotopic pattern and fragmentation characterization
•Intelligently organize data interpretation and visualization
HPLC-GC Chromatography
•Isolation of fractions and GC analysis in one process
•high separation, efficiency and high sensitivity
•Analysis of compounds avoiding sample preparation and cleanup
•Cost effective and time reduction
•Analysis of volatile and non-volatile in the HRGC
•Simplified method adjustment and new methods development