Photometric determn. of total bound nitrogen in water or soluble solid - e.g. dyestuff by alkaline oxidn. to nitrate with excess oxidant and conversion of excess oxidant to prod. not interfering with determn.

摘要

In the rapid determn. of the total bound N content of aq. liquors and water-soluble solids by measuring the nitrate (I) obtd. by oxidising the N, the novel features are that: (a) the conditions are made alkaline before oxidn.; (b) oxidn. is carried out under alkaline conditions, using excess oxidant (II); (c) after complete oxidn. of N to (I), excess (II) is converted to a prod. not interfering with (I) determn.; and (d) (I) is determined photometrically. The turbidity resulting from redn. is removed, pref. by sedimentation, filtration or addn. of a masking agent, pref. complex-formers, acids or acid salts. Photometric determn. is carried out directly; or indirectly, pref. by converting (I) to a deriv., esp. a nitrophenol or phenol oxidn. prod. obtd. by adding a phenol. USE/ADVANTAGE - The process is useful for determining N in water and water-soluble dye-stuffs. The technique can be carried out on site with few instruments and simple appts., it is reliable (typical variation coefft. 2.1%) and is friendly towards the environment, since no Cd is added, as in the determn. of nitrite.