By Anonymous on Monday, March 27, 2000 - 07:02 am:
I have been getting high recoveries on a Shimadzu LC10AT. Placebo is 15% glycerin/7.5% EtOH (w:v). When samples are analyzed against stds w/placebo added, recoveries are OK, but 2% high when analyzed against the "normal" std. BUT on an HP1100, this effect is not seen, recoveries are 99-100% with both normal standard and std w/placebo added. I need to resolve this issue to complete a method validation, so help is greatly appreciated.
By Anonymous on Tuesday, March 28, 2000 - 04:22 pm:
It would be helpful to have more information:
What is the dilution solvent solvent if there are any? Concentration range, wavelength (if were UV detec) and reference lambda on HP1100. How does the blank (placebo) run look like on Shimadzu compared to HP1100?
Chromatographic conditions?
Regards.
By Anonymous on Wednesday, March 29, 2000 - 03:40 am:
Wavelength 280nm, diluent: 0.2% TEA,pH 3.5:ACN (2:1), There is a peak in the placebo, but is < 0.05% of active area. 1.0 mL/min, column temp 40C, autosampler 5C, 20uL inj. volume, mobile phase: 0.2% TEA, pH 6.5:ACN (60:40)
By lej on Wednesday, March 29, 2000 - 05:17 am:
The problem is most likely your autosampler. HP uses split loop and shimadzu SIL-10A and older autosampler does not. If you are using SIL-10A or older, references and sample must be disolved in the same solvent, which is not the case in your metod. If you want to use SIL-10A (or older) autosampler you must use internal reference.
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