Recently I received sequencing results from my universities sequencing core. 85% of my library was assigned to a barcode that was not supposed to be in my library. I had 27 samples in total, and the other 27 have very low coverage because of this contaminated bar code.
I prepare DNA sequencing libraries pretty routinely and have never had this problem. Additionally, I used this same adapter plate less than a week ago and it worked fine (IDT for Illumina TruSeq DNA UD Indexes (96 indexes, 96 samples)). I was wondering if anyone has ever had this problem and has any advice or recommendations for me.