Hanna Instruments HI 83200C User Manual

Page 5

• Proper use of the powder reagent packet:

(a) use scissors to open the powder packet;
(b) push the edges of the packet to form a spout;
(c) pour out the content of the packet.

USING CUVETTES

• Proper mixing is very important for reproducibility of the measurements. The right way of mixing a

cuvette is specified for each method in the related chapter.
(a)

invert the cuvette a couple of times or for a specified time: hold the cuvette in the vertical position. Turn
the cuvette upside-down and wait for all of the solution to flow to the cap end, then return the cuvette
to the upright vertical position and wait for all of the solution to flow to the cuvette bottom. This is one
inversion. The correct speed for this mixing technique is 10-15 complete inversions in 30 seconds.

This mixing technique is indicated with “invert to mix” and the following icon:

(b)

shaking the cuvette, moving the cuvette up and down. The movement may be gentle or vigorous.
This mixing method is indicated with “shake gently” or “shake vigorously”, and one of the following
icons:

shake gently

shake vigorously

The instructions listed below should be carefully followed during testing to ensure most accurate results.
• Color or suspended matter in large amounts may cause interference, and should be removed by

treatment with active carbon and filtration: refere to Sample Preparation Chapter (page 17).

• Ensure the cuvette is filled correctly: the liquid in the cuvette forms a convexity on the top; the bottom

of this convexity must be at the same level as the 10 mL mark.

COLLECTING AND MEASURING SAMPLES

• In order to measure exactly 0.5 mL of reagent with the 1 mL syringe:

(a) push the plunger completely into the syringe and insert the tip into the solution.
(b) pull the plunger up until the lower edge of the seal is exactly on the 0.0 mL mark.
(c) take out the syringe and clean the outside of the syringe tip. Be sure that no drops are hanging

on the tip of the syringe, if so eliminate them. Then, keeping the syringe in vertical position above
the cuvette, push the plunger down into the syringe until the lower edge of the seal is exactly on
the 0.5 mL mark. Now the exact amount of 0.5 mL has been added to the cuvette, even if the
tip still contains some solution.

USING LIQUID AND POWDER REAGENTS

• Proper use of the dropper:

(a) for reproducible results, tap the dropper on the table for several times and wipe the outside of the

dropper tip with a cloth.

(b) always keep the dropper bottle in a vertical position while dosing the reagent.

TIPS FOR AN ACCURATE MEASUREMENT

(c)

(a)

(b)

(a)

(b)