46 CHROMATOGRAPHY
RAPID perfluorinated alkyl acid ANALYSIS P
Dr Shun-Hsin Liang presents some recent research using LC-MS/MS
erfluorinated alkyl acids are manmade fluorochemicals that are
used as surface-active agents in the manufacture of a variety of products, such as firefighting foams, coating additives, textiles and cleaning products. Tey have been detected in the environment globally and are used in very large quantities around the world. Tese fluorochemicals are extremely persistent and resistant to typical environmental degradation processes. As a result, they are widely distributed across the higher trophic levels and are found in soil, air, groundwater, municipal refuse and landfill leachates. Te toxicity, mobility and bioaccumulation potential of perfluorooctanesulphonic acid (PFOS) and perfluorooctanoic
acid (PFOA), in particular, pose considerable potential adverse effects for the environment and human health. Such effects include carcinogenicity, toxicity, hormonal effects, immunological effects and endocrine disruption. Due to exposure risk and the likelihood of these detrimental impacts, PFOS and PFOA have both come under regulatory scrutiny and many countries have restricted their use and are establishing threshold levels in drinking water and other matrices. In Directive 2013/39/ EU (an amendment to the Water Framework Directive), PFOS is named as a “Priority Substance” with very challenging environmental quality standards. PFOS was also listed in the Stockholm Convention on Persistent Organic Pollutants in 2009, and PFOA is currently being considered for inclusion in this international treaty, which is aimed at global protection of human and environmental health. In addition, EU
Directive 2006/122/ECOF now prohibits the manufacture and use of PFOS in the EU, and this directive also considers PFOA to present a risk profile that is comparable to PFOS. Similarly, PFOS is already regulated under the European Chemicals Agency’s REACH regulation EC No. 1907/2006, and PFOA is currently identified as a “Substance of Very High Concern” and has been placed on the REACH candidate list.
Challenging analysis Perfluorinated alkyl acid analysis can be challenging because these compounds are chemically different from most other environmental contaminants. Tey are difficult to quantify because some are more volatile than others, and they also tend to be more hydrophilic and somewhat reactive. In addition, fluorochemicals are present in polytetrafluoroethylene (PTFE) materials, so excluding the use of any PTFE labware throughout the sampling and
Fig.1. Longer lists of targeted perfluorinated alkyl acids can be analysed in eight minutes (10 minute total cycle time) on a 5 µm Raptor C18 SPP column using LC-MS/MS
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