By Kenny Yeoh on Tuesday, August 19, 2003 - 08:16 pm:
Hi all, I am working with some analysis of pesticide residue, I notice a funny observation that when I inject a mixture of pesticide standard (1uL) consist of (Acephate, Methamidophos and Monocrotophos) only two peak has shown out. On the other hand, when I inject the standard individually, three of them appear at really different retention time, why one peak disappears? Anybody has come across this problem? How to solve this problem?
RT for individual pesticide standard :-
Acephate : 6.37 minute
Methamidophos : 5.31 minute
Monocrotophos : 8.91 minute
Column used : DB 1 30m x 0.25mm
Condition used :
Injector : 280 oC
Detector : 300 oC
Flow rate : 0.9 ml/min
P/S : Methamidophos is metabolite for Acephate.
By Anonymous on Tuesday, August 19, 2003 - 10:37 pm:
dun know
By Anonymous on Wednesday, August 20, 2003 - 03:06 am:
which peak disappears ?
By kennyyeoh on Thursday, August 21, 2003 - 06:34 pm:
Acephate peak is disappear.
By Anonymous on Sunday, August 24, 2003 - 10:13 am:
Did you check your standard prep?
It sounds like you forgot to add "Acephate" to the mixture.