Determination of short-chain chlorinated paraffins in gull egg samples by gas chromatography-mass spectrometry.

Abstract

Chlorinated paraffins (CPs), otherwise known as polychlorinated n-alkanes, are chlorinated derivatives of paraffinic hydrocarbons used for years in a wide variety of industrial applications such as lubricating additives and fire retardants, among others. They are very complex mixtures composed by a large number of congeners, homologues and isomers, resulting in a great variety of physical and chemical properties. Among CP mixtures, short-chain chlorinated paraffins (SCCPs, C10-C13) are well-known ubiquitous organic pollutants of great concern because they exhibit a high toxicity and persistence and cause adverse effects in the environment and in living beings. Fish-eating birds are exposed to these contaminants through their diet and can accumulate in their bodies and transfer to their offspring, causing toxic effects at individual level or to the whole colony. For this reason, they are in the spotlight of the international community since the United Nations Environment Programme Governing Council proposed them as a new candidate to the list of Persistent Organic Pollutants (POPs). In the present work, an analytical method for the determination of SCCPs in gull eggs was optimised and validated according to international guidance. The proposed method consists of a pressurised liquid extraction followed by a clean-up procedure with Florisil and quantification by gas chromatography-electron-capture negative ionisation-mass spectrometry (GC-ECNI-MS). The method provides good figures of merit with a high sensitivity, trueness and precision, achieving low limits of detection (0.04 ng/g wet weight). The established methodology was applied to the analysis of SCCPs in egg samples from two gull species (Larus michahellis and Larus audouinii) collected in several natural parks and protected areas from Spain with the aim of evaluating the real impact of these pollutants in the environment using a non-invasive way of monitoring, and to propose measures to minimise their adverse effects on the living organisms.