High performance liquid chromatography-(HPLC)
(HPLC)-High performance liquid chromatography
· HPLC is a product of the scientific effort towards optimization of the conventional column chromatography.
· This method uses an extremely high pressure. The flow rate therefore is high and the experimental time is shortened considerably.
· This technique is suitable for both analytical and preparation purposes.
· The technique may be used with small amounts of sample (pico gram)
· It is popular for the separation of polar compounds such as drug metabolites, which, in general are poorly resolved by other techniques.
· Thus, it may apply the principle of adsorption, partition, ion-exchange, exclusion, and affinity chromatography.
Working principle
· It is a technique for separation identification and quantification of components in a mixture.
· It is especially suitable for compounds which are not easily volatilized, thermally unstable and have high molecular weights.
· The liquid phase is pumped at a constant rate to the column packed with the stationary phase.
· Before entering the column the analysis sample is injected into the carrier stream.
· On reaching the column the sample components are selectively retained on the basis of physico-chemical interactions between the analyte molecules and the stationary phase.
· The mobile phase moving at the steady rate elutes the component based on the operating conditions.
· Detection techniques are employed for detection and quantification of the eluted components.
INSTRUMENTATION
Application
· Pharmaceutical applications.
· Environmental applications.
· Applications in forensics.
· Food and flavor.
· Application in clinical tests.
Advantage
· It offers a quick, automated and highly accurate method to identify certain chemical components in a sample
· It is highly efficient and uses a pump rather than gravity, to force a liquid solvent through a solid adsorbent material
· It is accurate and highly reproducible.
· HPLC run cans can be performed with minimal training.
Disadvantage
· HPLC is costly, complex and doesn’t work for all samples
· HPLC does have low sensitivity for certain compounds, and some cannot be detected as they are irreversibly adsorbed.
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