Lecture 18

High Preformance Liquid Chromatography I

ColumnInjector Detector

Chromatograph

Data Processing

Zone broadening:The van Deemter equation

uCu

BAH

H - plate heightu - flow rate

Stationary phase in HPLC

Chemically inert

Non-soluble in any imaginable mobile phase

Thermal and chemical stability

Appropriate physical sorption of analyte

Shape: Uniform spherical particles

150 m2/g 300 m2/g

Si OH+

Cl Si

CH3

CH3

R-HCl

Si O R

CH3

CH3

Si

Si OH

Si OH

+ Cl2SiR2

-2HClSi O

SiR2

OSi

NH2

CN

O OH

OH

octadecyl

octyl

phenyl

amino

cyano

diolPolar phase

Nonpolar phase

Percentage of solvents having the same eluent strength

B - acetonitrile CH3CN

constant

constant constant 162

2

2

2

W

t

W

t

W

tN

r

rr

Width W is proportional to retention time tr

‘general chromatography problem’

Solution of GNP: gradient