By Bella Vulfova on Wednesday, February 5, 2003 - 05:55 pm:
Test for triclosan ( mobile phase:10mL of Acetic Acid, 270mL of H2O and 720 mL of Methanol; standard solvent -100% Methanol, sample solvent-about 2.5% Water and 97.5% methanol; column - Nucleosil C18, 5um, 4.6mm x 15mm)showed different tailing factors for standard solution peak (0.86) and sample solution peak (0.96). What could be the reason for this? Second analyst received the same picture using different instrument and column ( the same type). His tailing factor was 0.96 for standard peak and 1.06,1.07 for duplicate sample prep.
Thanks to everybody who will answer me.
By David Blais on Thursday, February 6, 2003 - 08:50 am:
Perhaps the 2.5% water in the samples is cause for the (slight) increase in tailing. Try making the standard in 97.5% methanol, 2.5% water, inject, and calculate the tailing factor. This would be the easiest place to begin.
By GE on Thursday, February 6, 2003 - 08:57 am:
Hi,Bella,
Because you use different solvents for the standard and sample, and it makes sense that the standard should have a more tailing peak. Why didn't you use the same solvent or mobile phase to prepare the sample and standard.