This report uses the Agilent 7890A GC system configured with a chemiluminescence detector (NCD) to analyze 2-ethylhexyl nitrate in diesel fuel, and the results show that the NCD can provide the required sensitivity and selectivity.
The document details an alternative method to ASTM D4046 for determining alkyl nitrate in diesel fuel. It utilizes an Agilent 7890A GC system configured with a chemiluminescence detector (NCD) to analyze 2-ethylhexyl nitrate (2-EHN). The method offers high sensitivity and selectivity for nitrogen over carbon, allowing for the detection of 2-EHN at low concentrations without interference from hydrocarbon backgrounds.
| Inlet Temperature | 250°C |
|---|---|
| Column Type | HP-5MS |
| Column Dimensions | 15 m x 0.32 mm |
| Column Flow Rate | 3.9 mL/min |
| Oven Temperature Program | 60 °C {2 min), to 280 °C {8 min) at 20 °C/min |
| NCD Temperature | 200°C |
| Detector Pressure | 77 Torr |
| Dual Plasma Controller Pressure | 110 Torr |
| Burner Temperature | 905 °C |
| Hydrogen Flow Rate | 5 sccm |
| Oxidant Flow Rate | 10 sccm |
The ASTM D4046 standard test method uses spectrophotometry with a detection range of 0.03 to 0.30 volume percent.
The concentration determined for 2-EHN as nitrogen in pump diesel is 1.18 ppm.
The concentration determined for 2-EHN as nitrogen in B20 biodiesel is 18.7 ppm.
No, the method demonstrates high selectivity for nitrogen over carbon and analyzes nitrogen in diesel without suffering from any hydrocarbon interference.