Hi there,

I think you should follow the instructions of the manufacturer.

Hi Mariana, as a rule, free thiols (such as in DTT) bind very strongly to metals, including gold, silver, copper and cobalt.

I think that DTT will almost certainly ruin your cobalt column.

thiols form complexes with many transition metals, like Co.

Don't ruin your column!

http://www.nrcresearchpress.com/doi/pdf/10.1139/v72-563

Good luck

Hi Mariana,

I believe you are doing the classical His tag purification. Such His tag purification need to avoid DTT. However, new column such as iMac from GE Healthcare could resist to DTT stripping more (see GE high bounds columns or IMAC colomn from Pierce). The high quality standard now for His tag purification is to use low reduction buffer such as TCEP. See the advantage of TCEP buffer: http://info.agscientific.com/blog/bid/101786/Side-by-Side-comparison-DTT-VS-TCEP-Preferred-Reducing-Reagents

Good luck !

Dan