What is HEEDTA?

Someone first mentioned HEEDTA and followups referred to it, i.e.

>> I am in the process of mixing my own PMDD. A little while ago someone
>> posted a very nice discussion of the various chelating agents, EDTA,
>> DTPA, HEEDTA etc. Unfortunately I lost that mail. Could someone
>> please email me this post?

Is it a typo meant to be EDDHA (ethylene-diamine dihydroxyphenyl acetic
acid) or is it something entirely different?

Dave Whittaker                       ac554 at FreeNet_Carleton.CA
Gloucester, Ontario                  dwhitt at magmacom_com