This is an application note about improving data quality in the automated HPLC analysis of PNAs (PAHs)
This document presents an optimized method for the automated HPLC analysis of polycyclic aromatic hydrocarbons (PNAs), also known as PAHs. The study focuses on improving data quality by addressing issues with retention time stability and fluorescence detection sensitivity. Key improvements include the use of vacuum degassing to prevent quenching effects and thermostatting the column compartment slightly below ambient temperature to enhance resolution of critical peak pairs.
The authors utilized an Agilent 1100 Series HPLC system configured with a quaternary gradient pump, vacuum degasser, autosampler, thermostatted column compartment, diode-array detector, and fluorescence detector. The method achieved retention-time stability within 0.05–0.2% RSD and peak area precision below 2% in the low ng range. Additionally, the improved diode-array detection system allowed for the detection of PNAs at ppb levels with automatic identification via UV-Visible spectral library search.
| Column internal diameter | 2.1 mm |
|---|---|
| Solvent flow rate | 0.4 ml/min |
| Retention time stability | 0.05 — 0.2 % RSD |
| Peak area precision (low ng range) | below 2 % |
| Detection limit | ppb levels |
| Identification threshold | less than 1 mAUFS |
Thorough degassing prevents quenching effects in fluorescence detection and improves retention-time stability.
Thermostatting the column temperature slightly below ambient temperature improves the resolution of critical peak pairs.
Yes, an improved diode-array detection system allows identity confirmation automatically by UV-Visible spectral library search.