I am using KELPLUS ELITE-EX VA semi-automatic Kjeldahl distillation unit for nitrogen estimation. The salesman told me that unlike the older version; this version does not require making up the sample volume after digestion and we can directly attach the tube to distillation unit and entrap the liberated ammonia in boric acid (with mixed indicator) and than titrate it against standard acid (H2SO4 ). However, fitting titration value in the traditional formula is giving wrong underestimated result. What will be the correct formula for estimating nitrogen% using the above-mentioned device? I am using about 0.7 gram of sample, 30 ml of conc. H2SO4 along with digestion tablet for digestion of the sample. The temperature of the digestion unit reaches up to 400`C in final stages. After the completion of the digestion and cooling down of the sample, I am attaching the tube directly to the distillation unit. I have measured the amount of digested sample and found it is 20 ml. The distillation unit is drawing 40 ml of 40% NaOH to neutralize acid and steam digesting for about 9 minutes. To entrap the liberated ammonia, I am using 4% boric acid along with a mixed indicator of methyl red (7 ml mixed with 1000 ml of 4% boric acid) and Bromocressol green (12 ml mixed with 1000 ml of 4% boric acid). for the titration, I am using 0.1N H2SO4 . The titration value is coming as 2.57 for wheat grain and 1.6 for wheat straw. Now how to convert these value to N%?

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