Perfluoroalkyl and polyfluoroalkyl substances (PFASs), in particular perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), have been widely studied due to their persistence, distribution, toxicity and bio-accumulation in humans and the environment. These compounds can enter the environment through landfills (products containing stain repellents, food packaging), wastewater treatment plants (industry waste) and from the use of firefighting foams (aqueous film-forming foams [AFFFs]). The heavy use of PFAS compounds has led to their widespread presence in the environment, including in water, sediment and biota. In 2000, companies began to phase out the use of the eight carbon-chain and higher carbon-chain PFAS's (PFOS-related compounds and PFOA) and replaced them with their shorter-chain homologues or other types of non-fluorinated chemicals. The production of PFOA, which is commonly used in the production of polytetrafluoroethylene and used in food pan coatings, lubricants, paints, paper products and floor finishes, was completely phased out by industry in 2015.
In a recent study by Susan Genualdi et al., (FOOD ADDITIVES & CONTAMINANTS: PART A, 2017 https://doi.org/10.1080/19440049.2017.1361046 ), UCT’s QuEChERS kits (AOAC 2007.1, 6 g MgSO₄ with 1.5 g NaCl) and dispersive SPE (dSPE) sorbent (0.9 g MgSO₄, 0.3 g primary secondary amine [PSA], 0.15 g graphitized carbon black [GCB]) and were used for the extraction of PFAS in cranberries. In the extraction, a homogenate of 20 grams of cranberries was combined with LCMS grade water. The sample was ground for 1 minute at 5000 rpm. A 10 g portion of the homogenate (equivalent to 5 g cranberries) was placed in a 50 mL polypropylene (PP) conical centrifuge tube, spiked with 13C8 PFOA and 13C8 PFOS surrogate standards. 10 mL of dichloromethane and 150 µL of formic acid were added to the sample and the mixture was vortexed/shaken for 2 minutes. A salt pouch (6 g MgSO₄ and 1.5 g NaCl) was added, and the tube was shaken/vortexed for 2 minutes and centrifuged for 5 minutes at 10,000 rcf. 6 mL of the supernatant was transferred into a 15 mL PP conical centrifuge tube containing dSPE sorbent (0.9 g MgSO₄, 0.3 g PSA, 0.15 g GCB). The tube was shaken/vortexed vigorously for 2 minutes and centrifuged for 5 minutes at 10,000 rcf. 1 mL of the supernatant was transferred into a 15 mL PP conical centrifuge tube and internal standard was added prior to analysis by liquid chromatography-tandem mass spectrometry. To test the methodology, cranberry samples were spiked with PFOA and PFOS at 10, 20 and 40 ng per gm for method validation. All method recoveries fell within the required range of 60% to 115%. This study shows the efficiency and productivity that can be achieved by scientists using UCT’s famous QuEChERS Kits in the area of public food safety analysis. For more information regarding UCT’s QuEChERS Kits, methods and applications please visit https://sampleprep.unitedchem.com/products/quechers.