By Zane Zhang on Thursday, June 7, 2001 - 11:56 pm:
I was handed over an evaporative light scattering detector to set up a method for analysing glyceral monostearate. As I was told, this detector was new.
However, when I started to set up the method, I noticed a baseline drifting when I used 100% acetonitrile as mobile phase at 1 mL/min flow rate without column. The evaporation temperature was 40 °C and nebulizer gas pressure was 2.8 bar.
Under the manufacturer's instruction, I tried to clean the detector by using 100% acetonitrile and 100% water with a temperature gradient from 50 to 100 °C in two hours, alternately and repeated twice.
The result is when I use 100% water as mobile phase under same condition, there is no baseline drifting observed.
However, when I use 100% acetonitrile as mobile phase, I still can observe the drifting. And the drifting rate is 1.3 mV/hour.
I tried to increase the evaporation temperature to 50 and 60 °C. At both temperatures, I could see the drifting when I used 100% acetonitrile as mobile phase at 1 mL/min.
I tried to contact the manufacturer again, they could not offer me any better idea.
Could any one give me some advice?
Just in case I can not solve the problem, does this kind of drifting (1.3 mV/Hour) effect the HPLC analysis qualitatively and quantitatively? And by how much, normally?
By bill lyons on Friday, June 8, 2001 - 01:42 am:
What pumping system are you using?Sounds like your acn is washing something out of the system.
By zane on Monday, June 11, 2001 - 11:05 pm:
I am using HP1050
By bill lyons on Tuesday, June 12, 2001 - 08:37 am:
The H.P. 1050 has a dampner.Is it oil filled?
Might the dampner membrane be ruptured?
By zane on Thursday, June 14, 2001 - 12:06 am:
Thank you and I will check it.
However, why there is no drifting when I use 100% water?
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