Polycyclic aromatic hydrocarbons in Antarctic ice core : prior study by homogeneous liquid-liquid extraction and high-performance liquid chromatography

Abstract

Organic contamination has been less investigated in Antarctic snow and ice than in other matrices due to analytical operational problems. In this study, the concentration of 14 Polycyclic Aromatic Hydrocarbons was determined in a shallow firn core by Homogeneous Liquid-Liquid Extraction and High–Performance Liquid Chromatography with a Fluorescence Detector. This investigation aimed to develop a simple analytical methodology for future application directly in fieldwork, taking advantage of the simplicity and small sample volumes. The analyte recoveries were 71–99% considering a 100 ng L⁻¹ initial concentration of each compound, with a relative standard deviation of 1.1–9.9%. Analytical sensitivity/ detection limit/ quantification limits varied from 7.8/ 20.3/ 67.6 ng L⁻¹ for fluoranthene to 0.6/ 1.5/ 5.1 ng L⁻¹ for anthracene. These analytical parameters allow us to apply the method to real samples. We found visible differences at various firn core depths when considering the sum of total analytes under study. The highest total concentration was 741 ng L-1 and the lowest one 134.9 ng L-1. The methodology can be applied without mixing samples with adequate analytical parameters, and it can preserve the firn core temporal resolution, which is an advantage for application in fieldwork.