JCU
User
Fresh Boarder
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Precision issues - 2007/02/19 08:40
Dear Experts,
I am noticing poor agreement between my replicate samples. I am analysing thyroxine and am finding typically that there is a 1% difference between the replicates (calibration samples) and up to 2% in the actual samples. The actual samples are the thyroxine extracted from tablets, using mobile phase and filtered (0.22u).
Peak purity analysis says that the peaks are pure but this loss of precision is worrying. What could I do to rectify this situation? I can't see any leaks.
Varian HPLC Prostar, PDA, C18, 0.2%Phosphoric acid/Acetonitrile 45:55, 255nm, 1mL/min, column warmed:35deg.
kind regards
Martina
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