[Histonet] Eosin leaching

[Debra Siena]

Hi Histonet,


Eosin bleaching is usually due to the alcohols that are used after the eosin, if you are in a humid area, the alcohols can actually absorb water from the humidity in the air. This may mean a change of how often you rotate or change the alcohols, possibly more often than you did during the winter months when usually less humid.  Also if you use a graded alcohol after the eosin, maybe worth looking into going straight to 100%, I usually always recommend at least 3 changes 100% alcohol for 1 minute and 3 changes of xylene for 1 minute.  If the last alcohol in your staining line is pink, it means that there is eosin and that means that there is water.  Eosin loves water and loves to come out of solution into the one containing the water.  I have even seen pink xylene in some staining lines due to water in xylene, however, not enough that it has turned cloudy yet but still have a bit of water.  Xylene will tolerate about .5% water before becoming too milky or cloudy to use.  Also when you rotate your solutions make sure that you dry the containers well before  refilling and by graduating the levels of the alcohols and xylenes to make sure that your last container completely covers the slides. Lastly, adding a 95% alcohol before your eosin, if you don't have one may help to keep excess water out of your eosin which will cause the eosin to break down faster, again eosin loves water.  Just spouting off the top of my head but hope something helps out.

Debbie Siena
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