Development of an analytical method based on LC-MS/MS for the determination of perfluorinated compounds in fish samples


Fàbregas i Rué, Céline


Since the 1940s, perfluorinated compounds (PFCs) have been widely produced and used in a wide range of applications due to their unique properties. These same physicochemical properties grant them persistency, toxicity and in some cases a bioaccumulative ability. For that reason, several PFCs were included in the Stockholm Convention as persistent organic pollutants (POPs). The principal exposure routes of PFCs have been studied leading to the conclusion that dietary exposure (more specifically the consumption of seafood) was the main contributor. Consequently, the development of an analytical method that determines the level of PFCs in fish has become a relevant subject.
In this work, a previous analytical method has been optimized to determine 13 PFCs in muscle fish samples, by liquid chromatographycoupled to tandem mass spectrometry (LC-MS/MS). Perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), perfluorododecanoic acid (PFDoA), perfluoro-n-tridecanoic acid (PFTrA) and perfluoro-n-tetradecanoic acid (PFTeA) were the target compounds. Firstly, the mass spectrometry conditions were optimized for the new analytes added (PFDA, PFUnA, PFDoA, PFTrA and PFTeA).
An evaluation of the preparation of standards was carried out to study the stability and solubility of the analytes and be able to select the solvent to use. The results show that the analytes are not degraded during a week independently of their storage conditions. Also, it has been demonstrated that the lower solubility in water, especially for the heavier compounds, leads to a loss of the analytes during the preparation of the standards due to its adhesion. Three different extraction methods were also tested to choose the one that provided a better accuracy and precision. The method selected provided recoveries in a range of 39-91% and %RSD from 2.4 to 10.0%. Once the extraction method was selected, quality parameters such as the linearity, the limits of detection (MDL: 0.004 to 0.79 ng g-1 ww), quantification (LOQ: 0.011 to 2.7 ng g-1 ww) and matrix effects were calculated and evaluated. In the same way, the internal standard method was used to study the recoveries of different fish samples, obtaining a range from 70 to 130%. Lastly, the determination of PFCs in different fish samples was determined. The concentrations of PFCs obtained ranged from 0.011 to 2.7 ng g-1 ww and were compared with the bibliography.



Díaz Ferrero, Jordi
Gómez-Canela, Cristian  


IQS SE - Master’s Degree in Analytical Chemistry