| Low Sensitivity |
Possible Causes |
Action Required |
| Dirty reaction chamber |
Clean reaction chamber |
| Clogged frit restrictor |
Clean or replace the frit restrictor |
| Leaks in the purge system |
For VCl3 reagent, check if reagent vacuum distills, if not confirm Teflon sleeve on NaOH trap is tight. |
| Replace septum |
| Confirm Swagelok connections are tight, ferrules are present and no glass is present in fitting. |
| Confirm connections to filter are tight. |
| Purge gas flow too high or too low |
Record cell pressure when frit restrictor is open to atmosphere (filter line disconnected), then adjust needle valve to match cell pressure when purge system is connected to frit restrictor. |
| Clogged hydrophobic filter |
Clean or replace filter |
| Water bath temperature too low (VCl3 reagent) |
Set water bath to 95° C |
| |
| Poor Repeatability |
Possible Causes |
Action Required |
| Leaks in purge system |
See above |
| Syringe contaminated or leaking |
Clean syringe and needle (should get no peak with empty syringe injection) |
| Replace syringe |
| Sample not injected into reagent (for µL volumes) |
Adjust volume of reagent so that end of needle is below reagent levels |
| |
| VCl3 Reagent Vacuum Distills |
| Possible Causes |
Action Required |
| Purge flow rate too low |
Adjust flow rate to match cell pressure when frit restrictor is open to atmosphere |
| |
| High Baseline or Rising Baseline |
| Possible Causes |
Action Required |
| Leaks in purge system |
See above |
| Dirty Purge Vessel |
Clean purge vessel with laboratory detergent |
| Injection of material slowly converted to NO (e.g., L-NAME or other nitro compounds when using the VCl3 reagent) |
Nitro-containing inhibitors (L-NAME, nitro-arginine, 7-nitroindazole) cannot be used with VCl3 reagent. |
| Replace reagent. |
| |
| Peaks observed without injections |
| Possible Causes |
Action Required |
| Leaks in purge system |
See above and also check for leaks in tubing from purge gas regulator to purge vessel |
| Contamination in reagent |
Will sometimes see peaks with VCl3 reagent due to contamination; allow the reagent to purge for 10-15 minutes. |
