LaMotte COD3 Plus, Руководство оператора

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APPENDIX
Ammonia in water occurs in two forms: toxic unionized ammonia (NH
3
) and the
relatively non-toxic ionized form, ammonium ion (NH
4
+
). This test method measures
both forms as ammonia-nitrogen (NH
3+
–N) to give the total ammonia-nitrogen
concentration in water. The actual proportion of each compound depends on
temperature, salinity, and pH. A greater concentration of unionized ammonia is present
when the pH value and salinity increase.
1. Consult the table below to fi nd the percentage that corresponds to the
temperature, pH, and salinity of the sample.
2. To express the test result as ppm Unionized Ammonia Nitrogen (NH
3
–N), multiply
the total ammonia-nitrogen test result by the percentage from the table.
3. To express the test result as ppm Ammonia Nitrogen (NH
3+
–N), subtract the
unionized ammonia-nitrogen determined in step 2 from the total ammonia-
nitrogen.
10°C 15°C 20°C 25°C
pH FW1 SW2 FW SW FW SW FW SW
7.0 0.19 — 0.27 — 0.40 — 0.55 —
7.1 0.23 — 0.34 — 0.50 — 0.70 —
7.2 0.29 — 0.43 — 0.63 — 0.88 —
7.3 0.37 — 0.54 — 0.79 — 1.10 —
7.4 0.47 — 0.68 — 0.99 — 1.38 —
7.5 0.59 0.459 0.85 0.665 1.24 0.963 1.73 1.39
7.6 0.74 0.577 1.07 0.836 1.56 1.21 2.17 1.75
7.7 0.92 0.726 1.35 1.05 1.96 1.52 2.72 2.19
7.8 1.16 0.912 1.69 1.32 2.45 1.90 3.39 2.74
7.9 1.46 1.15 2.12 1.66 3.06 2.39 4.24 3.43
8.0 1.83 1.44 2.65 2.07 3.83 2.98 5.28 4.28
8.1 2.29 1.80 3.32 2.60 4.77 3.73 6.55 5.32
8.2 2.86 2.26 4.14 3.25 5.94 4.65 8.11 6.61
8.3 3.58 2.83 5.16 4.06 7.36 5.78 10.00 8.18
8.4 4.46 3.54 6.41 5.05 9.09 7.17 12.27 10.10
8.5 5.55 4.41 7.98 6.28 11.18 8.87 14.97 12.40
1
Freshwater data from Trussel (1972).
2
Seawater values from Bower and Bidwell (1978).
Salinity for Seawater values = 34% at an ionic strength of 0.701m.
Testing
Appendix
COD3 Plus Colorimeter 10.16