multi N/C pharma HT
Troubleshooting
113
Error
Carry-over
Cause
Remedy
¡
Insufficient syringe flushing.
¡
Flush the dosing syringe with sample
before the next injection. To do this, edit
the method and enter a "3" in column 1
under Rinse cycles, no flush is usually re-
quired for all further measurements. En-
ter "0" here in the table columns.
Error
Low results
(general)
Cause
Remedy
¡
The catalyst is used up.
¡
Replace the catalyst.
¡
The system is leaking.
¡
Check the system for leaks.
¡
Faulty dosing.
¡
Check the dosing.
Error
Low results for TC, TOC, NPOC and TNb
analyses
(TIC analyses OK)
Cause
Remedy
¡
The catalyst is used up.
¡
When using the platinum catalyst and
measuring in differential mode (neutral
to slightly alkaline samples):
The catalyst can be regenerated.
Inject ultrapure water that has been
acidified six times (pH <2).
Recommendation: Measure one or two
sample vessels with acidified ultrapure
water per analysis series.
¡
Replace the catalyst.
¡
After replacing the catalyst, perform cal-
ibration.
Error
Low results for TIC analyses
(TC, TOC, NPOC
analyses OK)
Cause
Remedy
¡
No phosphoric acid in the reagent bot-
tle.
¡
Refill the bottle.
¡
Incorrect sample dosing.
¡
Check the dosing.
Error
Low results for TNb analyses
Cause
Remedy
¡
The catalyst is used up.
¡
Replace the catalyst.
¡
The sample concentration is above the
calibrated range.
¡
Observe the calibrated range.
¡
Use quadratic regression.
¡
If possible, calibrate dependent on the
matrix.
¡
For analysis of unknown substances, use
low concentrations if possible. If possi-
ble, dilute the sample.
¡
Use synthetic air as a carrier gas.
Error
Unusual peak shape during TC and TNb
analyses
Cause
Remedy
¡
The catalyst is used up.
¡
Note: Low results also occur at the same
time. Regenerate or replace the catalyst.
¡
Unsuitable integration criteria.
¡
Check the integration criteria in the
method.
¡
Measuring range for CLD exceeded.
¡
Dilute the sample.
