Chromatography (with 100% Errorless answers)

LC correct answers chromatographic technique in which the mobile phase is a liquid Advantages of LC vs. GC correct answers 1. LC can be applied to the separation of any compound that is soluble in a liquid phase (biological compounds, synthetic/natural polymers, inorganic compounds) 2. liquid mobile phase allows lc to be used at lower temps than required by GC 3. retention of solutes in LC depend on their interaction with BOTH the mobile phase and stationary phase (gc based only on interaction with stationary phase...LC more flexible in optimizing separations - change either stationary or mobile phase) 4. lc detectors are non-destructive Disadvantages lc vs. gc correct answers 1. LC is subject to greater peak/band boradening (much larger diffusion coefficients of solutes in gasses vs. liquids) low performance correct answers -lc methods that use large, non-rigid support material -poor system efficiencies and large plate heights -broad peaks, poor LOD, long separation times, low operating pressures -ex: column chromatography low performance advantages correct answers simple system requirements low cost popular in sample purification used in removal of interferences from samples HPLC correct answers -small, uniform, rigid support material -good system efficiencies and small plate heights -narrow peaks, low LOD, short separation times, high operating pressures and faster flow-rates HPLC advantages correct answers -fast analysis time -ease of automation -good LOD -preferred choice for analytical applications -popular for purification work HPLC disadvantages correct answers -more expensive -lower sample capacities Elution correct answers retention and elution of solutes in LC depends on interactions of solutes with both the mobile and stationary phases strong mobile phase correct answers solvent that quickly elutes solutes from the column this occurs if the mobile phase is very similar to the stationary phase inits intermolecular interactions with the solutes polar solvent would be a strong mobile phase for a column containing a polar stationary phase