Metrohm 794 Basic Titrino - Manual (Page 184)

6.3. User methods
794 Basic Titrino
180
6.3.14 "P2O5Fert""
Determination of P
2
O
5
in fertilizer.
TIP method with submethods "P2O5-1" and "P2O5-2"
Electrode: 6.0232.100 combined pH glass electrode, at measuring input 1.
additional instrument: 765 Dosimat, connect to 794 Basic Titrino via Remote line.
Titrant: c(NaOH) = 1.0 mol/L.
Reagents: c(HCl) = 1.0 mol/L
Sodium oxalate sat.
Sample: Pipette exactly 10 mL liquid fertilizer into the titration vessel. Add 5 mL
c(HCl) = 1.0 mol/L and dilute with 40 mL dist. water.
Fill the Dosimat with sodium oxalate solution and adjust the dosing vol-
ume to 15 mL.
Sequence: P2O5Fert is startet and the submethod P2O5-1 titrates the sample to the
dihydrogenphosphate and determines the excess of dispensed titrant. An
activating pulse starts the Dosimat dispensing the sodium oxalate solu-
tion. After the waiting time of 30 s P2O5-2 titrates the dihydrogenphos-
phate. P2O5Fert calculates the content of P
2
O
5
.
Reference: Metrohm Application Bulletin Nr. 240.
P2O5-1 Titration of the first equivalence point of
H
3
PO
4
.
'pa
794 Titrino 01102 794.0010
date 2002-01-03 time 10:01 0
DET pH P2O5-1
parameters
>titration parameters
meas.pt.density 4
min.incr. 10.0 µl
titr.rate max. ml/min
signal drift 50 mV/min
equilibr.time 26 s
start V: OFF
pause 0 s
meas.input: 1
temperature 25.0 °C
>stop conditions
stop V: abs.
stop V 99.99 ml
stop pH OFF
stop EP 1
filling rate max. ml/min
>statistics
status: OFF
>evaluation
EPC 5
EP recognition: all
fix EP1 at pH OFF
pK/HNP: OFF
>preselections
req.ident: OFF
req.smpl size: OFF
activate pulse: OFF
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