Supercritical fluid chromatography introduction

1. PRESENTED BY MR.AMIT H.KANSE.
(M. PHARM ) RAJGAD DNYANPEETH
COLLEGE OF PHARMACY BHOR,PUNE.
QUALITY ASSURANCE TECHNIQUES
2017-2018
Supercritical fluid chromatography

2. Supercritical fluid
chromatography

3.  In SFC, the sample is carried through a separating
column by a supercritical fluid where the mixture is
divided into unique bands based on the amount of
interaction between the individual analytes and the
stationary phase in the coumn. As these bands leave
the column their identities and quantities are
determined by a detector
Supercritical Fluids
Supercritical temperature :For every substance
there is a temperature above which it can no longer
exist as a liquid, no matter how much pressure is
applied.
Supercritical pressure : For every substance
there is a pressure above which the substance can
no longer exist as a gas, no matter how high the
temperature is raised.

4.  Supercritical
 fluid:substance has
properties intermediate
between a liquid and a
gas, non-compressible
and high density fluid. ".
The temperarure and
pressure are higher than
critical temperature (Tc)
and critical pressure
(Pc) they are proper to
fluids

5. Theory
Part of the theory of separation in SFC is based
on the density of the supercritical fluid which
corresponds to solvating power. As the
pressure in the system is increased, the
supercritical fluid density increases and
correspondingly its solvating power increases.
There for, as the density of the supercritical
fluid mobile phase is increased, components
retained in the column can be made to elute.
This is similar to temperature programming in
GC or using a solvent gradient in HPLC.

6. Instrumentation:
 Mobile phase
 Stationary Phase
 Pump
 Injection System
 Oven
 Column
 Detector

7. Mobile phase:
There are a number of possible fluids which may be
used in SFC as the mobile phase. Mostly CO2 is used.
The main disadvantage of carbon dioxide is its inability
to elute very polar or ionic compounds. This can be
overcome by adding a small portion of a second fluid
called a Modifier fluid. (alcohols, cyclic ethers,
acetonitrile and chloroform)
The addition of the modifier fluid improves the
solvating ability of the supercritcal fluid and
sometimes enhances selectivity of the separation

8. Stationary Phase
Same as those for GC and LC, with some modification.
 Silica/Alumina
 Useful for non-polar compounds
 Lead to irreversible adsorption of some polar solutes
 Widely used polar Stationary Phase are
 Polysiloxanes:- stable, flexible Si--O bond lead to good
diffusion.
 Substituted with chemical groups for selective interaction
with analyte
 Polymethylsiloxanes:- increase efficiency in separating
closely related polar analytes
 Cyanopropyl polysiloxanes:-useful for compounds with -
 COOH

9. Pumps
In contract to HPLC pumping system, pressure rather
than flow control is necessary and pulseless
operation is more critical.
In general, the type of high-pressure pump used in
SFC is determined by the column type. For packed
columns, reciprocating pumps are generally used,
while for capillary SFC syringe pumps are most
commonly employed.
Reciprocating pumps allow easier mixing of the
mobile phase or introduction of modifier fluids.
Syringe pumps provide consistent pressure for a
neat mobile phase

10. Injector
 Injection in SFC is usually achieved by
switching of the content of a sample loop into
the carrier fluid at the column entrance by
means of a suitable valve. For packed column
SFC, a conventional HPLC injection system is
adequate, but for the capillary column SFC, the
sample volume depends on column diameters
and small sample volumes must be quickly
injected into the column, therefore
pneumatically driven valves are used.

11. Detectors
 SFC is compatible with both HPLC and GC
detectors. As a result, optical detectors, flame
detectors, and spectroscopic detectors can be
used. However, the mobile phase composition,
column type, and flow rate must be taken into
account when the detector is selected as they
will determine which detector is able to be
used. Some care must also be taken such that
the detector components are capable of
withstanding the high pressures of SFC.

12. Applications
 SFC finds use in industry primarily for separation of chiral
molecules, and uses the same columns as standard HPLC systems. SFC is
now commonly used for achiral separations and purifications in the
pharmaceutical industry
 Fossil Fuels and Hydrocarbons
 Agrichemicals
 Drugs and Pharmaceuticals
 Polymers
 Explosives and Propellants
 Lipids
 Carbohydrates
 Industrial Chemicals
 Foods and Flavors
 Natural Products
 Metal Chelates and Organometallic Compounds
 Enantiomers