HighPerformanceLiquidChromatography SP2008

HighPerformanceLiquidChromatography SP2008 -...

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High-Performance Liquid Chromatography Page 1 of 12 High-Performance LC (HPLC) Called H - P due to reduced particle size ----> increases resolution. SP A A SP A A So, HETP is decreased with smaller particles. H = A + B/u x + Cu x A is also reduced due to homogeneous particle size. Decrease C As a result, can Increase u x and thus decrease B
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High-Performance Liquid Chromatography Page 2 of 12 But, small particles mean huge resistance to solvent flow ----> High Pressures must be used to obtain reasonable flow rates. P = 7 - 40MPa (70 - 400 atm) @ 2 mL/min Use strong materials like SS tubing! Stationary Phase Support - Microporous Silica: 5 - 10μm Pellicular Silica: (not porous); reduced efficiency; higher pressures
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High-Performance Liquid Chromatography Page 3 of 12 Liquid - Liquid Partition Chromatography Concept Chemical modification of silica surface - react silanol groups. Si-OH + X-Si-R Si-O-Si-R + HX CH 3 CH 3 CH 3 CH 3 CH 3 CH 3 Si-O-Si-R The siloxane bond will hydrolyze at pH>8 and pH<2. Care must be taken in aqueous solutions.
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HighPerformanceLiquidChromatography SP2008 -...

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