What is the best quality controlled LIMITED QTY-Dinucleotide Standards Formamido Adenine Dimer d (PfpA) (50 µg)?

The LIMITED QTY-Dinucleotide Standards Thymine Glycol Guanine Dimer d from Ncbi publications supplied next week by Genprice is the best choice!!! The catalog number is 801214 and the price is 66 EUR.