The simple answer is that it takes longer to make a high quality, modified oligonucleotides reproducibly. TriLink was formed in 1996 largely in response to the poor quality of modified oligonucleotides available from many vendors. We developed very methodical protocols geared to the manufacture of highly modified products. Our protocols require a great deal of attention to detail, as much of the work must be done manually to ensure success. Additionally, our purification methods are very time consuming, and we include 1-2 days for the analysis of products prior to shipping.