What is the purity of an unpurified oligo?

The crude oligo will contain full length product and n-1 failure sequences. Our 2'-ACE synthesis chemistry has very high coupling efficiencies, resulting in ~ 99% incorporation at each step. Any growing oligo that does not receive the next base in the sequence is capped and thus prevented from 'growing' incorrectly. Thus, the full length product will have the complete correct sequence and any shorter fragments will have complete sequence fidelity, but represent truncated oligos. The percent of full length product is calculated by: 0.99exp(n), where 0.99 = the coupling efficiency and n = the number of couplings (length of the oligo - 1). For example, for a 21-mer, the calculation is 0.99exp20 = 0.82, or 82% full length material with the rest representing truncation products.