Agilent Technologies 7890A Troubleshooting Manual page 4

4 GC Not Ready Symptoms
4
Baseline Rise During Oven Temperature Program
Poor Peak Resolution
Peak Tailing 34
NPD 34
Peak Boiling Point or Molecular Weight Discrimination Poor
For any inlet operating in split mode with any detector
For any inlet operating in splitless mode with any detector
Sample Decomposition in Inlet/Missing Peaks
Peak Fronting 37
Noisy Detector, Including Wander, Drift, and Baseline Spikes
Noisy baseline 38
Baseline wander and drift
Baseline spiking 40
Figure 1. Cyclic spiking
Figure 2. Random spiking
Low Peak Area or Height (Low Sensitivity)
FID Flame Goes Out During a Run and Attempts to Reignite
FID Baseline Output Above 20 pA
FPD Flame Goes Out During a Run and Attempts to Reignite
FPD Output Too High or Too Low
FPD Low Peak Areas 47
FPD Large Peak Width at Half-Height
FPD Baseline Output High, > 20 pA
NPD Solvent Quenching
NPD Response Low 51
NPD Baseline Output > 8 million
NPD Adjust Offset Process Not Functioning Properly
NPD Low Selectivity 54
Negative Peaks Seen with TCD
TCD Baseline Has Dampened Sinusoidal Noise Trailing Peaks (Ringing
Baseline) 56
TCD Peaks Have Negative Dip on Tail
GC Never Becomes Ready
33
39
40
40
41
44
46
48
49
50
52
55
57
60
32
35
35
35
36
38
43
45
53
Troubleshooting