Question

1. Qualitative vs.Quantitative analysis for both High Performance Liquid Chromatography(HPLC) and High Performance Thin Layer Chromatography(HPTLC)

Answer 1

Qualitative analysis for HPLC:

1. The sample components are known and peaks within the chromatogram need to be assigned to the known components.

(or)

2. The sample is a complete unknown which you are attempting to characterize.

Quantitative analysis for HPLC:

1. Know the compound you are analyzing.

2. Establish a method for analyzing samples containing the known compound.

3. Analyze a sample or samples (the standard) containing a known concentration or concentrations of the compound to obtain the response due to that concentration (called ‘Calibration’).

4. You may analyze a number of these samples with different concentrations of the compounds of interest if your detector has a non-linear response (referred to as ‘multi-level calibration’), or if a wide concentration range is to be measured in the samples.

5. Analyze the sample containing an unknown concentration of the compound to obtain the response due to the unknown concentration.

6. Compare the response of the unknown concentration to the response of the known (standard) concentration to determine how much of the compound is present.

Quantitative analysis for HPTLC:

HPTLC is an enhanced form of TLC. A number of enhancements can be made to the basic method of TLC to automate the different steps, to increase the resolution achieved and to allow more accurate quantitative measurements, i.e. to find how much of the sample is present.

Qualitative analysis for HPTLC:

In a similar way, in order to find what is the unknown sample, qualitative HPTLC is performed.