INSTRUCTION MANUAL CODE 80188 REV E
Jun/2018
(It can be modified without notice)
Page: 42
J
.P. SELECTA s.a.u.
Autovía A-2 Km 585.1 Abrera 08630 (Barcelona) España
Tel 34 937 700 877 Fax 34 937 702 362
e-mail: [email protected] - website: http://www.jpselecta.es
% Protein =
P
2
x 100 x F
P
0
P2: Nitrogen (mg).
P0: Sample weight (mg).
F: Protein factor.
6.5 Titration and Protein contents (%) calculation
Prepare the titration burette with the reagent usually HCl 0.25N.
Slowly dispense the HCl 0.25N on the Erlenmeyer stirring it at the same time.
Titrate until the colour changes (end point at pH 4.65).
From the HCl volume (ml) consumption on the titration, the Kjeldahl Nitrogen (mg)
is calculated:
Nitrogen (mg) = 14 x Volume
HCl
(ml) x Normality
HCl
And, from the nitrogen we calculate the sample protein content:
6.4 Analysis interruption
Press «STOP» to abort the analysis.
Note: The analysis interruption, left on the unit rests not neutralized that will cor
-
rupts the following analysis. Run a cleaning operation (See 6.2) before to run new
analysis.
• Insert the sample tube. See 5.1
• Select mode «MANUAL» or «AUTOMATIC» and initiate the sequence.
• Wait for the end of distillation. Buzzer sound.
• Empty the sample tube.
• Open the safety door.
• Remove the sample tube. See 5.2
• The unit is completely prepared to analyse the following sample. Any operation
of cleaning is needed, unless any malfunction has occurred during the analysis.
Visual Checking during the analysis:
Some visual checking can be applied from the colour that takes the solution on the
collector or in the sample tube.
This checking is useful at the beginning to set the optimal parameters or to solve
unit malfunctions.
Visual Checking on the sample tube: (Using CuSO
4
Catalyst)
When the NaOH volume is sufficient, the sample becomes blue. (If not, program
more NaOH on the following a analysis)
Visual Checking on the collector:
The initial colour must be the fixative solution colour (Violet with mixed indicator
or Red with mixed indicator 5). If it is grey or green, it is because of not neutral
-
ized rests of the previous sample remains on the collector. On this case stop the
analysis and run a cleaning operation. See 6.2
Almonds 5,18
Nuts 5,30
Nut- peanuts 5,41
Jello 5,55
Soya 5,71
Barley, trenches, rye 5.83
wheat, whole flour 5,83
Flours (not whole one) 5,70
Rice 5,95
Corn 6,25
General 6,25
Saved 6,31
Milk and milky products 6,38
Common protein factors
