By droxy on Thursday, June 21, 2001 - 05:29 am:
I have SM5000 UV/DAD detector (LDC Analytical) and I analyse pesticides; about 3 min of each run I have a big single peak, then signal drops to 0 value and so remains to the end of the run. It happens every time I make an injection (no matter if it is a spiked sample or a standard). I've never had this problem before.
Have somebody had a problem like this? What may be the cause?
I appreciate any advice.
By Anonymous on Friday, June 22, 2001 - 05:13 am:
Details of the method will be helpfull, but at first guess this looks like you have column/mobile phase mismatch - everything eluting in void volume. Too strong mobile phase (like 100% acetonitrile)
By droxy on Sunday, June 24, 2001 - 11:43 pm:
I use acetonitrile + phosphate buffer mobile phase, gradient 30% to 50% MeCN 20 min., and C18 ODS column.
Anon, do you sugest pump problem? ...Maybe... I will check it.
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