HPSF stands for High Purity Salt Free. It refers to a purification method using gel filtration plates in a 96-well format, combined with centrifugation.
This size exclusion technique removes small molecular weight impurities, including salts, protecting groups, and short n–x sequences (typically <10mers).
lease note that longer n–x sequences, such as a 25mer in a 35mer synthesis, may not be fully separated using this method. HPSF purification is available for oligonucleotides up to 120 bases in length.