hi;
I have been working on a problem at my work.
we have 2 HPLC's in our lab,
an Agilent 1260 series with a variable wavelength detector
and a 1100 series with a deuterium diode
both have a ODS hypersil reverse phase ( 10 microns particle size and both same lengt and diameter ) column installed
we run test on XXX( patented )
= 3-[3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoyloxy]-2,2-bis[3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoyloxymethyl]propyl] 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate
and other additives . . .
with methanol as mobile phase, both systems operate on the same parameters ( flow, pressure, temp, wavelength, internal standard etc )
now here is the problem;
we put the exact same sample in each LC system and they each produce
very different results, even though the methods on the software integrations are the same ,
the average difference between each system's series of injection
is about 1.3 area %
however, each series of results produced by each LC has a very small standard deviation; wich would mean that each LC system is very accurate in itself and NOT compared to another system running the same sample
anyone who has any tip or clue or even the slightest idea
please reply