[Histonet] sample BRIGHT yellow color change immediately upon fixation

[Jennifer Wyffels]

I am fixing a sample that has a lot of glycoprotein in a gel-like matrix using a freshly prepared EM grade glut/para mixture in 0.1M Sorensons buffer.  I have fixed many samples previously but have one species where the sample turns from mostly clear to bright yellow but still transparent within a minute of adding fixative.  I’m searching for an explanation but was unable to find a similar description for other samples.  Note the fixative is fresh and not yellow at the onset.  Would appreciate any information.  Thanks, Jen