Theoretical plates and Assay of the sample

Respected all,
Can anybody tell me that How a theoretical plate of the column affects the assay of a sample and how much it can vary i.e. Standard deviation of the theoretical plates. kindly provide me with the datas.

Theoretical plates in column chromatography are directly related to the efficiency of its column. Therefore, it can assist in improving the resolution, which is directly proportional to the square root of theoretical plates’ number when all other variables are kept constant. This means the resolution will increase by a factor of two each time the number of plates is raised by four.

From all these things, it is clear that the more theoretical plates imply the better quality of separations as more equilibriums can be attained between stationary and mobile phases. Because of better resolution of chromatographic peaks you get accurate and precise analytical results.

Generally, number of theoretical plates in chromatographic column is certified by the column manufacturer. We can check in QC laboratory efficiency of column by determining facators such as number of theoretical plates, tailing & resolution factors etc. Please refer USP.

A HPLC column is the most critical component of the HPLC system. Quality of analytical results will greatly depend on its performance. Though it is possible to monitor the HPLC column condition by keeping track on number of theoretical plates you are advised to look for other signs such as :

  • Degradation of peak shapes
  • Variations in retention times
  • Sudden increase in backpressure
  • Poor resolution between peaks
  • Appearance of ghost peaks