Nitrogen, total lr, Ntot1 tc (lr), 5 - 25.0 mg/l n – YSI pHotoFlex Series User Manual
Page 51: 16 mm, Rn319

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03/2013
Note: Before using the test with your photometer for the first time, determine the reagent blank 
value.
YSI model no.:
Ntot1 TC (LR)
Category:
KT (reaction cell test)
Cell:
16 mm
Measuring range:
0.5 - 25.0 mg/l N
Add the contents of a
VARIO TN Persulfate 
Rgt. powder pack into a 
TN Hydroxide LR 
digestion cell.
With a pipette add 2.0 ml 
of sample, close the cell 
with the screw cap and 
mix vigorously for at least 
30 s. A small amount of 
solids may remain 
undissolved.
Heat the cell in the 
thermoreactor at 120 °C 
for 30 minutes.
Remove the cell from the 
thermoreactor and let it 
cool down in a cell rack.
Add the contents of a 
VARIO TN Reagent A 
powder pack, close the 
cell with the screw cap 
and mix for at least 15 s.
Allow to react for 3 
minutes.
Add the contents of a 
VARIO TN Reagent B 
powder pack, close the 
cell with the screw cap 
and mix for at least 15 s.
Allow to react for 2 
minutes.
Pipette 2.0 ml of 
prepared sample into a 
TN Acid LR/HR 
(Reagent C) reaction 
cell and close the cell 
with the screw cap.
Mix the contents by 
carefully swaying the cell 
(10 x / for approx. 30 s 
altogether).
Caution, the cell 
becomes warm!
Note:
Always clean the powder funnel prior to adding a 
reagent!
Allow to react for 5 
minutes.
Insert the cell in the 
photometer cell shaft 
and start measurement.
3:00
2:00
5:00
Nitrogen, total LR
Program no.
319
*RN319*
