Dithiol Phosphoramidite (DTPA) is discontinued and replaced by Dithiol Serinol Phosphoramidite (DTSPA), please see link below.
Thiol SS Serinol Dipod (DTSPA)
Thiol SS Dipod (DTPA) Dithiol Phosphoramidite (DTPA) is a disulfide-containing modifier designed to functionalize synthetic DNA or RNA with multiple thiol groups and can be incorporated at any position of the oligonucleotide. Each DTPA addition leads to two thiol groups. This modifier was designed for optimal tethering of oligonucleotides to a gold surface but it can also be used for multiple reactions with maleimides and other thiol-specific derivatives.
See Gene Link Manual for Gold Surface Conjugation for details
Gold Surface Thiol Conjugation
After synthesis, Gene Link normally supplies the oligo to the customer in the oxidized (disulfide) form. The disulfide bond can then be reduced with TCEP or dithiothreitol (DTT) to generate the fully active thiolated oligo by the customer in his/her own laboratory.
See Gene Link thiol reduction technical sheet for details
Thiol Reduction Protocol