Ammonium hydroxide vs Ammonium carbonate

[Charles Bird]

Jean-Francois Landry & Bernard Landry, J. Lep. Soc 48(1): 208, advocate
laboratory grade (30% ammonia, 70% water) ammonium hydroxide solution for
despatching microleps. The latest Bioquip Catalog does not have ammonium
hydroxide but has ammonium carbonate instead. The latter is in a powder
form, some of which is placed in the bottom of a collecting vial and
activated by the addition of some water. In other words, it would be used
as in the old fashioned potassium cyanide killing jars I used to use. 

My question is which of the above is best, ammonium hydroxide or ammonium
carbonate, and does anyone have any tips about their use? Could either be
used with a UV light trap, or would ethyl acetate be best?