[nf405]

can L-ascorbic acid reduce gold from 3+ to 0 charge?

To put the question in context I'm a physicist but my work involves a bit of chemistry. I know that ascorbic acid is only a weak reducing agent and I thought that the reduction to Au 0 was happening in my experiment because there is a gold surface there (colloidal gold present in solution) and they could be completely reduced at the surface but not elsewhere in the solution. But my co-worker reckons when he added a lot of ascorbic acid to sodium tetrachloroaurate (III) dihydrate colloidal gold was formed, which can only happen if you have gold atoms (not ions) because otherwise they repel each other and won't come together to form colloids.

If L-ascorbic acid can reduce gold from 3+ to 0 charge then under what conditions can this occur? would the amount of ascorbic acid you used have an effect on this?