Lovibond Tintometer MD 100 Manual De Instrucciones página 70

Chemical Method
Phenol Red
Appendix
Interferences
Persistant Interferences
1. Water samples with little Carbonate hardness* can lead to false pH values.
*K < 0.7 mmol/l ≙ total alkalinity < 35 mg/l CaCO
S4.3
Removeable Interferences
1. pH values below 6.5 and above 8.4 can produce results inside the measuring range.
A plausibility test (pH-meter) is recommended.
2. Salt error
For salt concentrations below 2 g/l, no significant error, is expected due to the salt
concentration of the reagent tablet. For higher salt concentrations the measurement
values
have to be adjusted as follows:
Salt
content per
sample in
g/l
Correction
according to Kolthoff (1922)
1)
according to Parson and Douglas (1926)
2)
Bibliography
Colorimetric Chemical Analytical Methods, 9th Edition, London
EN Method Reference Book 1.0
30 60
(seawater)
-0.15 -0.21
1) 2)
pH-value T / M330
.
3
120 180
-0.26 -0.29
2)
EN
2)
71