You are a consultant in a chemical laboratory and are responsible to suggest suitable extraction techniques for different chemical analysis. Based on the info described in the below cases, i) Propose an extraction technique for the below two projects; ii) Support your answer with three reasons. a) Determine several phthalates, some organic endocrine disruptors, in a bottled water sample. The concentrations of the phthalates are supposed to be very low (ppb levels only). b) Determine benzo[a]pyrene, an organic carcinogen, in a rubber handle sample from a bicycle at ppm level. Pyrethroid insecticides are group of organic chemicals that bind tightly to soil and sediment; therefore they usually are at low levels in environmental waters (ppb levels). These pesticides may affect wild lives if they are over-used and should be monitored. In a long-term environmental monitoring program, river water samples are routinely collected from several points near an agricultural site for pyrethroid insecticides analysis. Discuss the pros and cons employing solid-phase microextraction (SPME) technique for doing such an analysis. a) With aid of a flow diagram, briefly describe the flow of solvent extraction by an accelerated solvent extraction (ASE) system. b) For collecting constituents for food production, such as extracting vanillin (the vanilla favour in ice-cream) from vanilla beans, we prefer supercritical fluid extraction (SFE) rather than ASE. Discuss two advantages of SFE over that of ASE in such an application.