Warning: This synthesis produces toxic nitrogen dioxide gases and handles corrosive acids. This should be performed in a fume hood with gloves.
First get 10 grams of inositol and add 25 mL of concentrated nitric acid. With a condenser, reflux the mixture for three hours. Eventually gas production will cease and the mixture should be allowed to cool. Add enough cold water to make the total volume 100 mL. Add an additional 50 mL of glacial (100%) acetic acid. Place the mixture on an ice bath and stir.
With continuous stirring, add in 40 g of potassium hydroxide in small portions. Be careful as it will produce a lot of heat and may bubble over. Allow time between each addition to allow the mixture to cool and settle down before adding the next portion.
Once all of the potassium hydroxide is added and the mixture is cool. Take it off the ice bath and continue stirring it overnight.
Filter out the red potassium rhodizonate precipitate and wash it with 100 mL of isopropanol. Then let it dry overnight.
Remove the chunks of potassium rhodizonate and grind them with a spatula into a powder. And then transfer into a vial.
Dissolve as much as possible of 0.3g of potassium rhodizonate in 100 mL of 5% acetic acid solution. Apply this solution to absorbent paper and rub it onto the item to be tested for lead. A violent, purple, or brown color is strong indication of lead.