Total Phosphorus Determination Steps for Water Samples:

Turn on the digestion instrument power, select the total phosphorus digestion mode (125°C, 30 min).

2. Power on the main unit and preheat.

3. Prepare several clean and dry colorimetric tubes on the colorimetric tube rack.

1. Accurately measure 5ml of distilled water and add it to the blank reaction tube.

2. Accurately transfer each water sample, sequentially adding them to the other reaction tubes.

When the total phosphorus value of the water sample is between 0~2mg/L, take 5ml of water sample.

② At 2~20mg/L, collect 0.5ml of water sample and add 4.5ml of distilled water.

1. Add 1ml of total phosphorus reagent (1) (including blank) sequentially to each digestion tube.

2. Tighten the degassing tube cap and shake evenly.

The dissolver beeps briefly upon reaching the set temperature, indicating to insert the digestion tube into the digestion hole, cover the protective shield, and press the "Confirm" button to start the dissolver's timing digestion process.

After dissolution is complete, the dissolution instrument's buzzer will sound a long beep to alert you. Press any key to cancel the long beep. Place the dissolution tube on the dissolution tube rack to cool to room temperature (either natural cooling or water cooling is acceptable).

After cooling to room temperature, add 0.2ml (4 drops) of Total Phosphorus Reagent (II) sequentially, cover and shake well, then let it stand for 30 seconds (including blank).

2. Add 0.3ml (6 drops) of Total Phosphorus Reagent (III) sequentially, cover and shake well, then allow to stand for 10 minutes to develop color.