This document describes the application of HPLC with ELSD for high-resolution analysis of triglycerides in cooking oil. ELSD detection offers higher sensitivity and adaptability compared to RI and UV, enabling the detection of low levels of contaminants. The author used a PLRP-S 100Å column and Agilent's ELSD detector for the analysis, and presented a chromatogram of unadulterated cooking oil.
The document details a method for analyzing the complex composition of triglycerides in cooking oil. It explains that gradient elution is required for high resolution separation and that Evaporative Light Scattering Detection (ELSD) is preferred over RI or UV due to solvent interference issues. The note highlights the suitability of PLRP-S 100A columns for this analysis due to their small pore sizes and high surface areas.
Specific instrumentation and conditions are provided, including the use of an Agilent ELS detector with specific settings (neb=40 °C, evap=40 °C, gas=1.6 SLM) and a PLRP-S 100A 5 um column. The method utilizes a gradient of Acetonitrile and Dichloromethane with a flow rate of 0.5 mL/min and an injection volume of 10 pL.
| Column | PLRP-S 100A 5 um, 150 x 4.6 mm |
|---|---|
| Detector | Agilent ELSD |
| Nebulizer Temperature | 40 °C |
| Evaporator Temperature | 40 °C |
| Gas Flow | 1.6 SLM |
| Flow Rate | 0.5 mL/min |
| Injection Volume | 10 pL |
ELSD is unaffected by the optical properties of the solvents used in the gradient, whereas RI is not viable and UV can suffer from baseline disturbance.
Eluent A is Acetonitrile and Eluent B is Dichloromethane.
The sample concentration is 1 mg oil/mL.