Florida International University Practice Final Exam Department of Chemistry Modern Analytical Chemistry CHM-4130 Name: ______________________ ID#:________________________ Part I Definitions (4 points each) answer 5 out of 10 only!!! Using one or two sentences define or explain the construction and function: (use graphs or formulas if you need) 1) Relative retention time (RRT) for compound x using a retention time standard s 2) Distribution coefficient (K) of a compound being separated on a chromatography column 3) Crosslinked Poly(phenylmethyl)siloxane (5%phenyl) Stationary Phase 4) Electrospray ionization (ESI) 5) Soft Ionization technique 6) Size Exclusion Chromatography7) Chemical Ionization mechanism for a generic compound M using Methane as a reagent gas 8) Fast Atom bombardment (FAB) 9) Theoretical Plate Height (H) 10) Van Deemter Equation Part II Short Essay: (15 points each) answer 3 out of 4 only!!! 1) Describe the operation principle and construction of an electronic impact source (EI). Make sure you label each component and state its purpose. Include a basic ionization mechanism for a generic compound X. 2) Show a diagram and explain the operating principle of one of the following mass spectrometer analyzers: a) Quadrupole mass filter b) Ion-trap analyzer c) Double focusing (EBE or EB) mass spectrometer 3) Describe the instrumental setup and state the function of individual elements for one of the following systems. Be specific! Its worth 20 points: a) Capillary Column Gas Chromatograph with Flame ionization Detector b) High Performance Liquid Chromatograph with a Diode Array Detector 4) Describe in as much detail as you can two of these GC detectors. Make sure you mention their selectivity, sensitivity, as well as advantages and disadvantages : a) Electron Capture Detector (ECD) b) Flame Photometric Detector (FPD)c) Atomic Emission Detector (AED) Part III Problems: (20 points each) 1) As usual here is an analytical challenge and it has two parts! Be as creative as you possibly can but be sure you justify your proposal. Based on common sense and all you have learned during this semester tell me how we can interface these two systems: a) a gas chromatograph to a mass spectrometer b) a liquid chromatograph to a mass spectrometer Think about limitations such as vacuum vs. pressures, liquid vs. gases etc. Don't panic, there is more than one right answer. 2) You were hired to setup an instrumental analytical facility at a pharmaceutical company. Here are the problems you have to solve: After extraction of the active ingredients from saw palmetto you need to purify and identify the “active” and inactive ingredients. After doing some research you find that they are mostly large (MW>1000) fused aromatic rings with at least three ionizable carboxylic acids and three non-ionizable phenolic groups. The fragrance department is working on an imitation of designer cologne for men. They have the original product and they want to identify the volatile compound responsible for the smell. The guys working on making generic Viagra have a problem with metal contamination in the coating of the pills. They did make about 2 million tablets and they need to test for transition metal residues in the coating only! The rest of the pill is free of any impurities but they think they may have a lot of lead on the surface. Mary and Joe are still working at the company. Joe precision in his work is still poor and wants to keep his job. He asked you for some help. His peaks are horrible in terms of band broadening when he uses RPLC and runs on a 15 cm column isocratically (100 methanol). On top of that he is having a lot of trouble getting resolution of three important peaks. He knows for a fact that Mary is getting beautiful results with incredible resolution and nice peak shape but she is so competitive that does not want to share her secret. The folks on the production floor are having problems with solvent recycling. They recover most of the hexane and acetone they use but the mass balance of the benzene tells them that they are loosing about 40%. Since the solvents are re-used in the manufacturing process and aromatic solvents are not allowed in the final products they need to find a quick way to test for aromatic residues in the reuse solvents.“Your job here is to propose a way to solve the problems using instrumental analysis, there are multiple answers and if you use common sense, NO WRONG ANSWERS” just be sure to justify your line of thinking and describe why a particular instrument will be able to do the job. After all that is why we hired