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- Posts: 405
- Joined: Wed Jul 18, 2012 6:45 am
- Location: Germany
Does anyone have experience with Vancomycin (glycopeptide antibiotic) extraction from animal tissue?
The molecule is large (1450 Da) and highly polar. LC/MS/MS analytics is no problem with LOQ < 1 µg/L in water.
I tried extraction from tissues (liver, kidney and subcutaneous tissue) with the following methods:
1.) QuPPe-AO method => Recovery 0 %
2.) QuEChERs (buffered) => Recovery 0 %
3.) Homogenisation with excess water, centrifugation, filtration => Recovery < 10 %
3.) Homogenisation with lower amounts of methanol/water => Recovery < 10 %
4.) Homogenisation with metaphosphoric acid/methanol => Recovery < 5 %
5.) Homogenisation with water, cooking in microwave => Recovery 50 % (one-time lucky shot, sadly)
6.) Homogenisation with 0.3% metaphosphoric acid, cooking in microwave => Recovery < 20 %
6.) Homogenisation with less water, repeated cooking / resuspension of pellet in water bath at 80 °C => Recovery 20 - 30 %
7.) Addition of NaCl to 6. => Recovery 20 - 30 %
I tested for matrix effects => not significant, spiked blank extracts are OK.
I tested cooking stability => stable during mild cooking but not in the microwave
I have also tried to remove fat and debris with LLE (cyclohexane and dichloromethane) and dSPE (C18, PSA, diatomaceous earth) => no improvement
I hoped for literature because Vancomycin is an old molecule, but found only methods for plasma, urine and water.
Any further suggestions?
Thanks a lot
Jörg
PS.: I know from literature that Vancomycin is not metablised in liver, so I don't think that we see enzymatic degradation or similar biological effects.