Where are you located? There is at least one company in the USA that sells a pre-mix micro-nuternt blend. But I would need to find the link again. Although if you are are in a pinch, I understand that adding "Epsom salt" (Magnesium Sulfate) and "calcium nitrate" to miracle grow (a soil based fertilizer) can work. But I have never tried it, and personally don't know anyone who has. So I can't tell you how well it works, I also can't tell you what quantity to mix, or if making your own soil base
nutrients (without micro nutrients) it will be compatible. So trial and error would be your best bet there.
That's all about chemistry, and some elements will bond with others, rendering them useless to plants (even if they were water soluble to begin with). Not to mention plant chemistry is very complex, even involving temperature, humidity, type of plant, plant cycle, light (photosynthesis) etc., as to how the plants use the available nutrients, and what they need. That's why I'm wondering why anyone would want to try to make their own nitrients without having what they need available to them, even if they had a clear understanding of all the chemistry involved.