Explain about Low pressure gradient and High Pressure
gradient systems in HPLC?

Answer Posted / venkata narayana

Answer:
In a high pressure gradient pump, each different mobile phase is delivered by an individual pump head and then the mobile phases are mixed at the pump outlet. In a low pressure gradient pump, different mobile phases are mixed using a valve before entering the pump head.


As a result of the fact that the low-pressure gradient design uses only one pump head, it is of lower cost. It can also use more types of mobile phase without significant increase of cost.


Since solvent mixing point is much closer to the column head in the high-pressure gradient design, it provides a much faster gradient. This is measured using delay volume. The value can be 50-300 uL for high pressure gradient pump and can be 2 to 3 times larger for a low pressure gradient pump. A small delay volume is important when the analysis time is short or the flow rate is low. If the delay volume is too large, it become impossible to obtain reproducible gradient run since the planed composition cannot reach the column head before a run is finished.

Is This Answer Correct ?    20 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

what is lod and loq ?,why use k2cr2o7 , kcl h2so4 in uv calibration ?,why use benzophenone & caffene acetone in hplc calibration ?,what is leading peak in hplc ?why we do the calibration of limit of stry light in hplc & uv ?

3180


why we use a particular hplc column for a particular compound give reasons?please

2263


What is the diference between residual solvents and organic volatile matter

1479


what is the importance of peak purity in HPLC and how we can calculate through manul(not software)?

3983


how require to set assay concentration for standard and sample?

359






Which parameter require to do for analytical method equivalency?

317


Describe your field experience sample type collected,sample techniques,field measurements taken and equipment used?

2271


How to start the dissolution development for unknown tab?

1138


how require to interprit the method precision data of hptlc?

291


in sampling of raw material which side is pasted sampled labels

1247


what type of question will ask in the interview of lab chemist.

2882


EXPLAIN THE CALCULATION PART OF AN KF TITRATOR CALIBRATION WITH SUITABLE EXAMPLE

2126


what is the difference between potentiometric titration and karl fischer titration?

2414


Why sodium hydroxide used for maintain pH of phosphate buffer

1822


Difference between the quantitative analysis and qualitative analysis?

618