Halogens are estimated by the Carius method, where a known mass of the organic compound is heated in a Carius tube. The halogen is precipitated as a silver halide (AgX), which is filtered, dried, and weighed to calculate its percentage.

Sulphur is estimated by heating a known mass of the compound in a Carius tube with sodium peroxide or fuming nitric acid. Sulphur is oxidised to sulphuric acid and precipitated as barium sulphate ($BaSO_4$) by adding excess barium chloride. The precipitate is filtered, washed, dried, and weighed.

Phosphorus is estimated by heating a known mass of the compound with fuming nitric acid, oxidising it to phosphoric acid. It is precipitated as ammonium phosphomolybdate, $(NH_4)_3PO_4.12MoO_3$, by adding ammonia and ammonium molybdate. Alternatively, it is precipitated as $MgNH_4PO_4$ using magnesia mixture, which on ignition yields $Mg_2P_2O_7$.