how to locate the root cause?

<p>recently  wo transfer one gradient method that  run successful on agilent conventional 1200 LC-DAD-MS(single Quadrupoles) system  to run on waters  Acqtuity uplc -pda -SQD system</p><p>the run time shorten from 30 mins to 10 mins now ,and we get good peak shape and resolutons .but there is one question  that one same sample solution  runing on two different syestem gets two different sample amount  we have get series of raw dates compared two system .what may cause the problem ? how to design the procedures to find the root cause ?</p>


  • You're showing us the final results in mg/kg - I assume you get your HPLC/UPLC results in unit of mass (mg, ug, ng) per unit of volume (mL, uL) and convert them to get the concentration in raw material (mg/kg), correct? Look carefully at raw data in mass/volume and how you convert it. Then look at both of your standard curves, especially residuals - this may cause you strange results even if R^2 is high.

  • thank you ! you are right ! we will check  whether the residual achieve the criterion