8
MI490 Photometer for edible oils
5. GENERAL TIPS FOR AN ACCURATE MEASUREMENT
The instructions listed below should be carefully followed during testing to ensure best
accuracy.
y
The official method EC 2568/91 recommends to work at room temperature, between
15 and 25 °C.
y
Whenever the vial is placed into the measurement
cell, it must be dry outside, and completely free of
fingerprints, oil or dirt. Wipe it thoroughly with
Mi0004
(tissue for wiping cuvets, see chapter ACCESSORIES)
or a lint-free cloth prior to insertion.
y
In order to avoid reagent leaking and to obtain more accurate measurements, it is
recommended to close the cuvet very well with the cap.
y
In order to measure exactly 1 mL of oil:
a. Push the plunger completely into the syringe.
b. Insert the syringe in the oil and push the plunger
up and down twice to rinse and eliminate air
bubbles; then 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. Then, keeping the syringe in
vertical position above the vial, push the plunger
completely down into the syringe.
y
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.
