I have some trouble with RNA extractions. I am trying to extract cells from mouse liver after collagenase P digestions and then I sort the cells with FACS. Then I extract RNA with this kit: https://www.thermofisher.com/order/catalog/product/AM1931. I use bioanalyzer Agilent2100 for migration and RIN calculation. In the track 1, there is RNA from total liver (the same liver from the same digestions) and tracks 2 and 3 RNA from cells sorting. There are 28S and 18S bands and another band below the 28S in cells sorting cells.

Have you ever seen this 3rd band before? Do you know what is it? If is contaminant, how can I do for eliminate this band?

Thanks for your answer.

Mickaël