A strange factoid about a zinc supplement

Seeking to calculate the percent by mass of the active ingredient in a tablet of zinc mineral supplement, an interesting fact was discovered. The zinc supplement is manufactured by Jamieson Laboratories of Toronto; the label amount is 10 mg zinc.1 These supplement tablets are utilized as analytical samples in an EDTA titration laboratory exercise for an introductory analytical chemistry course at Mohawk College.2

The zinc in the tablets is in the form of zinc gluconate. Wikipedia was consulted for the structure and molar mass of gluconic acid and hence of the gluconate anion.3 The article in Wikipedia is short, but an interesting statement and link caught my attention. A solution of zinc gluconate can be used by injection to necrotize the testicles of male dogs, rendering them neutered!!4

Gluconic Acid structural formula.


  1. Jamieson Zinc 10 mg: http://www.jamiesonvitamins.com/2159.
  2. Experiments for term 2 of the 2-year programs for health science, environmental, and biotechnology technicians: http://www.uclmail.net/users/dn.cash/experiments.html.
  3. Gluconic acid: https://en.wikipedia.org/wiki/Gluconic_acid.
  4. American Journal of Veterinary Research 2008: http://avmajournals.avma.org/doi/abs/10.2460/ajvr.69.1.140