Deniges Reagent

Mercuric Sulfate TS Deniges Reagent) Mix 5 g of yellow mercuric oxide (HgO) with 40 mL of water, and while stirring, slowly add 20 mL of sulfuric acid, then add another 40 mL of water, and stir until completely dissolved. 

Therefore, these reactions constitute a means to distinguish both sorts of barbiturs. This result must be connected to Denigds reaction used in analytical toxicology in order to search for barbiturics extracted in acidic medium. Deniges reagent is mercuric sulfate in a mixture of sulfuric and acetic acids ... 

Deniges reagent Mix 5 g of yellow mercuric oxide with 40 ml of water, add, slowly while stirring, 20 ml of concentrated sulphuric acid followed by 40 ml of water and stir until all the mercuric oxide has dissolved. Test for the absence of mercurous mercury as follows To 10 ml add... 

Mercury(II) sulphate reagent (0.2m) (for Deniges s test). To 40ml water add cautiously 10 ml concentrated sulphuric acid with constant stirring. Dissolve in this mixture 2.2 g mercury(II) oxide. 

---