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2000-OSM, F1
6-7
5. Baseline offset extreme. See "Baseline or Signal Offset (TCD)" or "Baseline or Signal Offset
(FID)."
6. Column broken or connection in the column train disconnected. Perform
Test Procedure 7
(Column Train Problems).
7. TCD Failure. Perform
Test Procedure 5
(TC Detector Balance) and
Test Procedure 6
(Filament
TCD Test), as applicable.
8. FID Failure. Perform
Test Procedure 17
(Verification FID Flame Is Ignited) and
Test Procedure
15
(FID Reduced Sensitivity), as applicable.
9. FPD Failure. Perform
Test Procedure 43
(FPD Gain Setting).
10. Low Zone Temperatures. See "TEMPERATURE CONTROL HARDWARE PROBLEMS" and
Test Procedures 21 through 27
.
11. Active stream is stream 9 (no inject occurs on stream 9). Change to correct active stream.
12. Check Method Table for correct entries. Perform
Test Procedure 33
(Checking Method Table
Configuration).
13. Sample Valve Failure. Perform
Test Procedure 1
(Carrier, Makeup, and Utility Gas Supplies)
and
Test Procedure 2
(Carrier and Makeup Gas Flow Adjustments), as applicable. Also see
"Baseline or Signal Offset (TCD)" and "Baseline or Signal Offset (FID)." Repair sample valve
(see "SAMPLE VALVE REPAIR" in Section 8). Check for correct stem volume and length.
14. Actuation solenoid valve vent is plugged or obstructed. Check and remove any obstruction.
15. Solenoid not moving. Replace solenoid valve, driver card, or Chroma I/O board.
Double Sampling
Symptom: The chromatogram peaks appear to have double apexes (see Figure 6-9). The trailing
peak apex is generally smaller than the leading due to the first having the greater sample size.
TIME
TIME
NORMAL
DOUBLE SAMPLING
Figure 6-9. DOUBLE SAMPLING
Cause: Double sampling problems are isolated to the sample valve. Generally the first injection
occurs when the valve is turned on (valve stem inserted into the injection chamber). The second
injection is made when the valve is turned off (the valve stem is withdrawn from the injection
chamber). Perform
Test Procedure 19
(Double Sampling).