| Hach rapid spectrophotometry was used to determine the ammonia escape concentration from flue gas denitrification device. By optimizing sampling flow rate, sampling probe temperature, absorbing solution concentration and consumption, and choosing appropriate color developing time, the testing result of Hach rapid spectrophotometry showed a high precision and accuracy in the range from 0.12 mg/m3 to 5.10 mg/m3. The detection limit of this method was 0.03 mg/m3. The relative standard deviations of 2 practical samples by 6 duplicate test were 1.2% and 0.1%, respectively. The results of ammonium certified standard materials were within the uncertainty of the standard values. The recoveries of 2 spiked samples with different concentration were 100% and 98.8%, respectively. Comparing this method with national standard method, no significant difference were detected in practical samples analysis results. |
