Skip to main content

Theoretical Plates 'N' and their Determination in HPLC Analysis

Theoretical Plates 'N' and their Determination in HPLC Analysis

Learn about the theoretical plates N and their calculation in HPLC using the retention time and peak width. This is a helpful parameter to determine the system suitability.

Theoretical plates are known as a measuring tool of HPLC column efficiency. Any chromatography column doesn't have any physical plate but it is a result of a mathematical calculation.

The columns having a high number of theoretical plates are considered more efficient in HPLC separation than the columns having less number of theoretical plates. A more efficient HPLC column will have a narrower peak than a less efficient column with less theoretical plates at the same retention time.

Related: Principle of HPLC

High column efficiency is needed to resolve the narrow peaks in the drug analysis. Hence the resolution of peaks also depends upon the column efficiency i.e. theoretical plates. Theoretical plates are calculated per meter length of the column and often called as Nm. As per the United States Pharmacopoeia (USP) following formula is used to calculate the theoretical plates of HPLC columns.

N = 16(Ve/Wb)2

Where,

N = Theoretical plates

Ve = Retention Time

Wb = Peak Width

Theoretical plates should be determined under specific set conditions; specifically, temperature plays an important role that alters the number of theoretical plates. Retention factor (k) of test solute used to determine the theoretical plates should be more than 5. Less than 5 retention factor can give an inaccurate number of theoretical plates.

Related: Resolution Factor, Tailing Factor, Theoretical Plates and Capacity Factor in HPLC

When comparing the efficiency of two columns; there should be same temperature conditions and retention factor (k) for a valid evaluation of their performance.

All the columns don’t have the same number of theoretical plates. Generally, it ranges between 8000-12000 but it also depends upon the flow-rate, viscosity of mobile phase and molecular of the compound to be analyzed. In reverse phase chromatography it is determined using simple hydrophobic compounds, like toluene, naphthalene or acenaphthene and mobile phase contains a higher concentration of organic solvents having low viscosity.

Related: Relative Response Factor (RRF) and its Calculation in HPLC Analysis

In general HPLC analysis, most of the analyzed compounds are more polar and their mobile phase has a higher concentration of water. The mobile phase having water is more viscous than the mobile phase having organic solvents.

When viscosity increases the count of the column theoretical plates decrease and this is the reason due to which the theoretical plates are found lower in practical use than the standard testing conditions.

Also see: HPLC Column Receipt, Checking and Regeneration

Labels:

Comments

Post a Comment

If you have any doubts, please let me know

Popular posts from this blog

Checklist for Audit in Sterile Area

Checklist for Audit in Sterile Area Checklist to verify the sterile manufacturing area before the audit. 1. Is there any SOP giving details for activity/ movement in the sterile area. 2. Verify the suitability of system for sanitization of hands. 3. Is there the SOP on entry-exit; gowning and de-gowning into the critical area available? 4. Verify the availability of following records:  Air pressure differential  Particulate monitoring  Temperature  Humidity  Microbiological monitoring by settle plate 5. Are these records available and maintained as per SOPs? 6. Check the above mentioned individual records. Are the entries within specifications mentioned in SOP/ MTPs. 7. Is the controlled copy of MTP pertaining to monitoring by settle plate available to plant person? 8. Are the location for settle plates identified and the chart/ layout available with plant? 9. Are the following areas monitored for parameters mentioned in step 4:  Air-lock to the critical ar...
Post a Comment
Read more

Aseptic Filling Process (Media Fill) Validation Protocol in Sterile Pharmaceuticals

Aseptic Filling Process (Media Fill) Validation Protocol in Sterile Pharmaceuticals Validation of sterile manufacturing process by media fill validation test as per PICS guidelines for aseptic validation or aseptic process simulation. 1.0 OBJECTIVE 1.1 To define procedures for validating and maintaining the validation of all aseptic filling processes and qualification of the quality of the product by system/facility/equipment. 2.0 SCOPE 2.1 This procedure applies to all aseptically filled sterile products intended for human use. 3.0 RESPONSIBILITY 3.1 The Validation personnel coordinate the aseptic filling validation program and write the sterile media aseptic filling processes reports. 3.2 Manufacturing personnel the sterile media aseptic filling processes and performs the sterile media fills. 3.3 QA personnel perform the sampling and assist with the IPQA monitoring required for each sterile media fill. 3.4 QC personnel to perform the testing and assist with the monitoring required fo...
Post a Comment
Read more

Blow Fill Seal (BFS) and Form Fill Seal (FFS) Technology in Sterile Manufacturing

Blow Fill Seal (BFS) and Form Fill Seal (FFS) Technology in Sterile Manufacturing Know about sterile pharmaceutical production using Blow Fill Seal (BFS) and Form Fill Seal (FFS) technology. Both of these techniques are used to manufacture  sterile pharmaceutical products   as parenteral (LVP & SVP), infusions, ophthalmic and inhalation products. These are automated techniques to prepare sterile products. The basic concept of the  FFS   and BFS is to reduce the  contamination   by forming the container, filling and sealing in a closed sterile chamber of the machine. There is no personnel intervention to reduce the chances of the contamination during the manufacturing of sterile products. It gives more production at very low operational cost with the high assurance of  sterility . Blow fill seal technology is widely used and accepted by the various pharmaceutical regulatory authorities as US-FDA and MHRA. The system is being used for over 30 years a...
Post a Comment
Read more