What is the difference between low pressure gredient and high
pressure gredient in hplc instrument?
Answer Posted / yojana
In a low pressure gradient pump, different mobile phase is
mixed using a valve before entering the pump head. In a
high pressure gradient pump, each different mobile phase is
delivered by an individual pump head and then mixed at the
pump outlet. The low-pressure gradient design is of lower
cost as it only use one pump head. It can also use more
types of mobile phase without significant increase of cost.
The high-pressure gradient design provides a much faster
gradient since solvent mixing point is much closer to the
column head. 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 ? | 22 Yes | 4 No |
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