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- Posts: 1
- Joined: Wed Feb 05, 2014 3:03 am
Hi to all...
I'd like to inquire and ask for assistance regarding my plasma sample.
Just wondering why can't i have a good linearity curve at
lower concentration level (0.1ng/mL, 0.5ng/mL, 1.25ng/mL) while at higher
concentration (5ng/ml, 7.5ng/ml, 10ng/mL) theres no problem at all.
same is true for both my standard solutions and spike plasma samples!?.
Im using a thermo LTQ XL ion trap LCMS.
mobile phase: 0.1% Formic Acid in Acetonitrile : 0.1% Formic Acid in Water (60:40)
Column: C18 2.1x50 1.9u
Flow rate: 100 uL/min
Inj vol: 10uL
Sample Preparation: SPE Bond Elut C18 (condition / apply plasma / elute)
Eluent: 90:10 Acetonitrile:0.1% Formic Acid in water
evaporate then reconstitute with MP (1:1) ratio
I'd like to inquire and ask for assistance regarding my plasma sample.
Just wondering why can't i have a good linearity curve at
lower concentration level (0.1ng/mL, 0.5ng/mL, 1.25ng/mL) while at higher
concentration (5ng/ml, 7.5ng/ml, 10ng/mL) theres no problem at all.
same is true for both my standard solutions and spike plasma samples!?.
Im using a thermo LTQ XL ion trap LCMS.
mobile phase: 0.1% Formic Acid in Acetonitrile : 0.1% Formic Acid in Water (60:40)
Column: C18 2.1x50 1.9u
Flow rate: 100 uL/min
Inj vol: 10uL
Sample Preparation: SPE Bond Elut C18 (condition / apply plasma / elute)
Eluent: 90:10 Acetonitrile:0.1% Formic Acid in water
evaporate then reconstitute with MP (1:1) ratio
