I have used a sailmakers needle to dispense a small amount of KMnO4. These are triangular and the flats will work as a small spatula. A few grains of the material can be picked up to add to the water. I carry a few sailmakers needles in my kit and one in my calendar book binding. Here is a picture of a sailmakers needle.
A dry stick can also be whittled to a small flat spatula shape also...just be sure it is dry.
Make sure you are very careful with the dry powders. Inhalation of the material or getting in the eye can be very harmful.