Metrohm 774 Oven Sample Processor - Manual (Page 158)

6 Appendix
774 Oven Sample Processor, Instructions for use 152
6.6 Validation / GLP
GLP (Good Laboratory Practice) demands, amongst other things, a peri-
odic inspection of analytical measuring instruments for reproducibility and
correctness on the basis of Standard Operating Procedure (SOPs).
Since this unit is not a measuring instrument as such, the user is advised to
include the 774 Oven Sample Processor as a part of an analysis system in
comprehensive validation of this system.
Inspection of the electrical and mechanical function groups of Metrohm
equipment can and should be performed within the framework of regular
servicing by technical staff of the manufacturer's company. All Metrohm
units feature start-up check routines which, when the unit is switched on,
check proper operation of the relevant modules. If no error message is dis-
played in this case, it can be assumed that the device is functioning cor-
rectly. Messrs. Metrohm also supply their equipment with integrated diag-
nostic routines allowing the user to check the function of specific modules
and localise the error or fault in the event of any faults or incorrect re-
sponses occurring. Diagnostic routines may also be integrated in a valida-
tion procedure.
Please refer to the Metrohm Application Bulletins 255/1 ("Validation of
Metrohm KF Titrators and KF Ovens according to GLP/ISO 9001") and
273/1 ("Validation of Metrohm KF Coulometers according to GLP/ISO
9001") for directives on elaborating Standard Operating Procedures for
checking a titration system. These Bulletins are available free of charge
from Metrohm.
Notes on the use of standard substances
If the 774 Oven Sample Processor is used primarily at high temperatures
(>150 °C), use a certified water-standard substance on the basis of potas-
sium citrate-1-hydrate (5.55 % water).
Recommended settings:
Oven temperature: 220 °C
Gas flow:
Approx. 40 mL/min
Sample size: 20 to 40 mg
Important! Since this solids standard features a high water content for the
determination with a Coulometer, it must be ensured that the moisture is not
transferred too quickly to the titration cell during the determination. If neces-
sary, further-reduce the gas flow. The measured value of the Coulometer
should never exceed 100 mV.