Thank you for contacting QIAGEN Technical Service.
Single-stranded DNA binds to the QIAquick column with similar affinity as double stranded DNA fragments that are half as long. Therefore, if the minimal length for dsDNA is 100 base pairs, then the minimal length for recovery of ssDNA would be approximately 200 nucleotides.
Unfortunately there is not an available list of “tested interfering chemicals.” Is there a particular chemical that is cause for concern?
However, R&D has found no inhibition in regards to the PCR purification kit for the following:
2% NP-40, Tween 20, Triton X-100, or Gelatine
3% SDS
10% Glycerol
10% Formamide
10% DMSO
1 Vol (=100 µl) Chloroform, Phenol, or Isoamylalcohol. Some phenol is found in the eluate.
1/10 Vol (= 10 µl) Butanol, Isopropanol, or Ethanol
15 % PEG 6000
15 % PEG 8000
10 mM DTT
25 µg / ml (= 2,5 µg) BSA

If anything I have written is unclear or if I can help you in any other way, please feel free to reply to this email or call me at the number below.  For 24/7 access to technical support, visit our online resources at <>.
Bryan N. Kahner, Ph.D.
Technical Service Scientist