PFAS, short for per- and polyfluoroalkyl substances, are a wide group of chemicals that consist of a polymer carbon chain where several of the hydrogens in the carbon chain have been replaced with fluorine atoms. PFAS have several beneficial properties, such as being inert, water-resistant, oil-resistant, flame-resistant and corrosion resistant. These same properties have however led to them being ubiquitous in the environment due to their frequent use in a variety of products and because of their persistence. PFAS have shown signs of bioaccumulation and having potential for harmful effects on the health of humans and the environment. There are several routes of exposure of PFAS, including through ingestion, inhalation, and absorption through the skin. The main route of direct exposure is thought to be through food, where the highest contribution is from fish. Ultra High-Performance Liquid Chromatography (UHPLC) combined with triple quadrupole tandem mass spectrometry (QqQ MS/MS) is a highly sensitive and versatile analytical technique that is well suited for PFAS analysis. However, optimization of the analytes of interest is required before analysis can take place. In this project several novel PFAS were optimized on an Agilent 1290 Infinity II UHPLC combined with an Agilent G 6495 Triple quadrupole mass spectrometer, and a method validation of an alkaline digestion sample preparation method was tested on three different fish matrices. Due to unsatisfactory results from this method validation, an altered method was then quickly tested with improved results. While the optimization was largely successful and the altered method shows promise, the sample preparation method still needs more work before analysis can be done on real samples