BUCHI KjelSampler K-377 - Manual (Page 27)

3 Technical data
27 K-375/376/377 Operation Manual, Version B
Measuring input: pH/mV input with 12 bit transducer for accurate resolution during the titration
Connection: electrode socket according to DIN 19 262 or BNC socket and reference electrode 1 x 4 mm socket
Measuring range Display resolution Accuracy* without sensor Input resistance ( Ω)
pH 0…14 0.01 0.05 ±1 digit > 5·10 12
mV –1400 ... +1400 0.1 2 ±1 digit > 5·10 12
Measuring range Display resolution Accuracy* without sensor
T [°C] –30…115 0,1 0,5 K ±1 digit
*Accuracy:
Indicated in terms of measuring incertainty with a confidence of 95%. In addition the measuring uncer-
tainty of the sensor has to be taken into account as well. For pH electrodes e.g.:
∆ pH=0.012...0.03
according to DIN 19 266, Part 3.
3 .3 Titration solution
The amount of sample and the concentration of the titrant should be optimized, so that the titrant
volume is between 3 and 17 mL (buret volume: 20 mL).
Table 3-16: Nitrogen expected
N-amount N-content Sample size Titrant Titrant concentration Titrant volume
5 mg N 0.5 % N 1 g H
2
SO
4
0.01 mol/L 17.8 mL
50 mg N 5 % N 1 g H
2
SO
4
0.1 mol/L 17.8 mL
100 mg N 10 % N 1 g H
2
SO
4
0.25 mol/L 14.3 mL
100 mg N 10 % N 1 g H
2
SO
4
0.5 mol/L 7.1 mL
200 mg N 20 % N 1 g H
2
SO
4
0.5 mol/L 14.3 mL
200 mg N 20 % N 1 g H
2
SO
4
1 mol/L 7.1 mL
Table 3-17: Protein expected
P-content P-factor N-content Sample size Titrant Titrant concentration Titrant volume
1 % P 6.25 0.16 % N 2 g H
2
SO
4
0.01 mol/L 11.4 mL
2 % P 6.25 0.32 % N 1 g H
2
SO
4
0.01 mol/L 11.4 mL
5 % P 6.25 0.80 % N 2 g H
2
SO
4
0.1 mol/L 5.7 mL
10 % P 6.25 1.6 % N 2 g H
2
SO
4
0.1 mol/L 11.4 mL
10 % P 6.25 1.6 % N 2 g H
2
SO
4
0.25 mol/L 4.6 mL
20 % P 6.25 3.2 % N 2 g H
2
SO
4
0.25 mol/L 9.1 mL
50 % P 6.25 8.0 % N 2 g H
2
SO
4
0.5 mol/L 11.4 mL
General recommendation
The correction factor for self prepared solutions is called titer.
The use of standardized titration solutions make a titer determination unnecessary.
Exact titrant concentration = concentration x titer
The titer of the titrant must be known. In case, it is unknown, it must be determined.
Example: Exact titrant concentration = 0.100 mol/L x 0.998