Metrohm 840 PC Control 5.0 / Touch Control - Manual (Page 280)

4.9 Electrode test for pH electrodes (ELT)
268
PC Control / Touch Control
Limit values of the three electrode types
Rating
Excellent electrode Good electrode Usable electrode
Electrode type "Standard"
Streaming potential 2.5 mV 3.0 mV 4.0 mV
Drift 2.0 mV/s 2.5 mV/s 3.0 mV/s
Slope min. 96.5 % 96.0 % 95.0 %
Slope max. 101.0 % 102.0 % 103.0 %
Response time 45 s 50 s 60 s
Lower limit Uoff –15 mV
Upper limit Uoff 15 mV
Electrode type "Gel"
Streaming potential 3.0 mV 3.5 mV 4.5 mV
Drift 2.5 mV/s 3.0 mV/s 4.0 mV/s
Slope min. 96.5 % 96.0 % 95.0 %
Slope max. 101.0 % 102.0 % 103.0 %
Response time 60 s 75 s 90 s
Lower limit Uoff –15 mV
Upper limit Uoff 15 mV
Electrode type "Non-aqueous"
Streaming potential 3.0 mV 4.5 mV 6.0 mV
Drift 5.0 mV/s 7.0 mV/s 9.0 mV/s
Slope min. 88.0 % 80.0 % 70.0 %
Slope max. 120.0 % 130.0 % 140.0 %
Response time 60 s 75 s 90 s
Lower limit Uoff –10 mV
Upper limit Uoff 70 mV