- TOC Analyzers and Sensors
- GE Autosampler
- Quality System Optimization Services
- Boron Analyzer (UPW)
- Leakwise Oil Detectors
- Nitric Oxide Analyzer
- Parts
- Accessories
- Software
- Standards and Vials
- Support Documentation
Visit us at:
NOA Liquid Sampling
A list of possible problems with the chemiluminescence detector appears below. If the problem is not listed below or assistance is needed, contact GE Analytical Instruments.
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). |
| 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. |
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. |