Determination of Extractable Organically Bound Fluorine (EOF) in Surface Water With Molecular Absorption Spectrometry

Introduction

A wide range of materials based on fluorinated organic compounds with highly desirable properties has been created during the last decades and their amount is constantly growing. The chemical resistance and physical properties of fluorinated organic substances are used in many everyday products and applications, from pharmaceuticals through fine and specialty chemicals to polymers. The consequence of the accelerating production of fluorinated organic substances is their increased occurrence in the environment. Some of these substances are already listed as persistent organic pollutants by the Stockholm Convention (Annex B -restriction) and the European water framework directive (WFD). 

Besides the known substances further toxic fluorine species can occur due to decomposition or microbial degradation. The determination of single compounds is time-consuming and cost-intensive. Therefore, a sensitive screening method of fluorinated organic compounds as sum parameter enables a fast monitoring of the environmental pollution. The presented method of the quantitative determination of extractable organically bound fluorine (EOF) as sum parameter in surface waters, recently developed by the Federal Institute of Hydrology, Germany, combines solid phase extraction (SPE) and molecular absorption spectrometry (MAS). 

The SPE is suitable for multiple enrichment of organic compounds as well as separation of interfering inorganic fluoride. This procedure can be simplified by the sample preparation device APUsim, that offers the flow speed control and allows simultaneous handling of up to six samples. The contrAA 800 with its integrated Xenon short arc lamp and its highresolution spectrometer offers low detection limits as well as the possibility to record molecular bands besides the atomic absorption. This allows the quantification of non-metals such as F via GaF molecular absorption.