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Question 6 Phthalates are commonly used as plasticizers in the manufacture of plastic bottles. The general structure of a phthalate is given below. There is concern that these compounds can leech from plastic over time and enter into the food-chain (e.g. drinking water from a plastic bottle) R2 A solid phase extraction protocol for such phthalates is detailed as follows. SPE cartridge C18/3 ml/500 mg sorbent Sample pretreatment: 5 ml of methanol was added to IL of water to be tested Sorbent conditioning - 2 X 10mL Tetrahydrofuran (THF), 2 X 10 ml methanol Equilibration - 10 mL of ultra-pure water Sample Loading 1000 ml of water was aspirated through the SPE sorbent Washing 10 ml of ultra-pure water Elution, 10 ml of THE was slowly aspirated through the sorbent and the eluted sample was dried under a stream of nitrogen to a concentration of 0.5 ml prior to analysis by GC. Discuss the role and purpose of each solvent in the SPE protocol. Include in your answer the reasoning behind the each solvent used in the protocol. Include in your answer why the solvent in the final eluate was evaporated to 0.5 ml