Q1) GC-FID

Q2)

GC-FID system having 10% Trifluoropropyl methyl di-methyl-polysiloxane as a stationary phase is used to separate components of a sample having 100 ppm decane and 100 ppm hexanol in acetone. At initial settings, decane is coming out at 4 mins (completely separated from acetone) and hexanol at 20 mins. The disadvantage of this run is that it is too long. Select all applicable suggestions that can reduce the retention time of hexanol. (Note: Trifluoropropyl forms hydrogen bonding with hexanol acting as hydrogen bond acceptor) Use oven program to increase the temperature after 4 mins into the run Derivatize hexanol, using esterification reaction with acetic acid, to form hexyl acetate Replace stationary phase with another having a lower percentage of Trifluoropropyl groups Increase the flow rate of the mobile phase Reduce the flow rate of the mobile phase Use oven program to reduce the temperature after 4 mins into the run Replace stationary phase with another having a higher percentage of Trifluoropropyl groups Increase the split ratio Change the solvent from acetone to hexane Reduce the length of the column Select all statements that are true about GC delivery system: Helium, usually used as carrier gas in GC analysis, is a flammable and toxic gas. Always chain or strap cylinders to stationary objects or wall whether in-use or in- storage. Regulators reduce the gas cylinder pressure to line pressure (60 - 100 psi), and then EPC system is used to reduce the pressure according to set parameters. The common concern among all gas cylinders is that they contain gas under pressure and poses physical hazard When moving gas cylinders, gas regulator should be kept installed at all times. Gas tanks should be completely emptied and only replaced when they hit 0 psi mark