To preconcentrate cocaine and benzoylecgonine from river water at the opening of this chapter, solid-phase extraction was carried out at pH 2 using the mixed-mode cation-exchange resin in Figure 27-18. After passing 500 mL of river water through 60 mg of resin, the retained analytes were eluted first with 2 mL of CH3OH and then with 2 mL of 2% ammonia solution in CH3OH. Explain the purpose of using pH 2 for retention and dilute ammonia for elution.
CH 01 6 September 2017 *First test 9/14* CHAPTER 2 GOAL: U nderstand how e lectrons are rranged in atoms Major Topics: - Light and Matter - Waves and Particles - Atomic Structures - Quantum M echanics SOME BACKGROUND: L IGHT Light is lectromagnetic wave. It’s field that is ropagating through space and o scillates regularly which are qualities of a wave. The wave does not move up nd down but he magnitude o f th ave. Speed of light is 3.00*10 /sm Wavelength varies while the peed f light stays constant. Wavelength is the length from ne mplitude maximum