HANNA INSTRUMENTS HI781-25 Marine Nitrate Low Range Reagents

Measurement Procedure

• Press the ON/OFF button to turn the checker on. All segments will be displayed for a few seconds, followed by “Add”, “C.1” with “Press” blinking.
• Using the 10 mL syringe, measure exactly 7 mL of sample into the large mixing vial.
• Using the 5 mL syringe, add exactly 4 mL of HI-781A-0 reagent into the large mixing vial.
• Add the content of one packet of HI-781B-0 reagent into the large mixing vial. Replace the cap and shake vigorously for 1 minute.
• Remove the plunger from the 10 mL syringe. Attach the syringe to the filter holder assembly using the threaded connection.
• Remove the cap from the mixing vial. Hold the syringe and filter holder assembly over a cuvette. Carefully pour the contents of the mixing vial into the back of the syringe.
• Very slowly push the plunger into the 10mL syringe until the 10mL cuvette has been filled up to the 10 mL mark and replace the cap.
• Insert the cuvette into the checker and close the cap.
• Press the ON/OFF button. When the display shows “Add”, “C.2” with “Press” blinking, the checker is zeroed.
• Remove the cuvette, unscrew the cap and add the content of one packet of HI-781C-0 reagent. Replace the cap and shake vigorously for 2 minutes.
• Insert the cuvette into the checker.

Tip for an accurate measurement

It is important that the sample does not contain any debris.

Whenever the cuvette is placed into the measurement cell, it must be dry outside and completely free of fingerprints, oil or dirt. Wipe it thoroughly with HI-731318 or a lint-free cloth prior to insertion.

Shaking the cuvette can generate bubbles, causing higher readings. To obtain accurate measurements, remove such bubbles by swirling or by gently tapping the cuvette.

Do not let the reacted sample stand for too long after reagent is added, or accuracy will be lost.

After the reading, it is important to discard the sample immediately, otherwise the glass might become permanently stained.

Four steps. One click. Instant Readout.

1. ‘Zero’ the Checker®HC with your vial inside

2. Place a 10ml water sample into the vial and add your reagent

3. Place your vial into your Checker®HC

4. Press the button and read the results