intelligent column selection for reversed-phase & new ... · pdf filethe van deemter equation...

2016 Waters Corporation 1
New LC Columns Technologies
Solid-Core particles
Peru October 2016
Ricardo Martnez

Solid-Core Particles

The Solid-Core Particle Column Advantage:
Greater Efficiency, Resolution, and
Throughput

CORTECS Extensions
Vision Statement
We are expanding the CORTECS brand by introducing
chemistries that will offer additional selectivities that
will allow scientists to achieve their separation
demands.

Agenda
Review of Solid-Core Particles
CORTECS Solid-Core Particle Columns
Column Benefits for Improved Laboratory Performance
Practical Applications of CORTECS Columns
Summary

Agenda

Solid-Core particles have been around since the 1970s
Waters Corasil I 30-80 m particles.
Today's modern core-shell particles are prepared by the multi-
layering of silica sols around a solid silica core.
FIB SEM Images
Solid- Core
Core
Part
icle
1.6 m

CORTECS Solid-Core Particle Characteristics
Solid- Core
Core
Part
icle
Attribute CORTECS
r 0.7
Particle Size 1.6 m, 2.7 m
Pore Volume 0.26 cm/g
Pore Size 90
Surface Area 100 m/g
FIB SEM Images
Solid- Core
Core
Part
icle
Fully optimized synthesis process
Mechanically strong particles
Particles have roughened surface
1.6 m 2.7 m
= 0 fully porous particle
= 1 nonporous particle
r = core diameter / particle diameter

Why are Modern Solid-Core Columns so Popular?
Provide higher efficiency when compared to fully porous
particles of equivalent particle size.
Provide lower backpressure when compared to fully
porous particles of equivalent particle size.
Efficiency
Pressure

Laboratory Impact
With highly efficient columns you have more resolving power.
More peaks are baseline resolved, easier to identify and quantify
With lower backpressure you can perform faster analysis
and/or use longer columns.
Run at higher flow rates, run more samples/ day.
Longer columns add more resolving power.
More resolving power & faster analysis = More information in less time.

More Efficient, How??? The van Deemter Equation the basics
The van Deemter equation describes empirically additive
sources of dispersion that result as a function of mobile phase
velocity and particle size.
ucu
baH
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
H-u

More Efficient, How??? The van Deemter Equationthe basics
The a-term was thought to be a constant dp and takes into account flow heterogeneity
ucu
baH
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
H-u
a-term

The b-term is the longitudinal diffusion term
which diminishes at high linear velocity
ucu
baH
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
H-u
a-term
b-term

The b-term is the longitudinal diffusion term
which diminishes at high linear velocity
The c-term is the mass transfer term which
increases at high linear velocity
ucu
baH
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
0
2
4
6
8
10
0 5 10 15 20 25 30
Linear Velocity u
H-u
a-term
b-term
c-term

What makes SolidCore Particles more Efficient than Fully Porous???
One of the major differences for small molecules is in the b-term:
1. The b-term is the longitudinal diffusion term and is the
easiest to explain and examine:
At the () optimum linear velocity the b-term
contribution is significant.
The impervious solid-core at the center of these
particles decrease the volume available for diffusion thereby
decreasing the b-term. Higher Rho-values lead to lower b-terms.
F. Gritti, G. Guiochon, J. Chromatogr. A 1221 (2012) 2 40 K. Miyabe, ANALYTICAL SCIENCES MARCH 2013, VOL. 29
0
2
4
6
8
10
0.0 0.5 1.0 1.5Linear Velocity cm/sec
H-u

Understanding Mass Transfer [Diffusion]: Fully-Porous Particles

Understanding Mass Transfer [Diffusion]: Influence of Particle Size
Diffusion distance is shorter with decreasing particle size resulting in a narrower, more efficient, chromatographic band

Understanding Mass Transfer [Diffusion]: Superficially Porous Particles
Fused Core Particle
Diffusion distance is short because the analyte band can only diffuse into the porous layer of material
../../../../Acq/water_van_deemter.exe

Agenda
CORTECS Solid-Core Particle Columns

CORTECS Column Family
UPLC Columns featuring 1.6 m solid-core silica particles
HPLC/UHPLC Columns featuring 2.7 m solid-core silica particles
Key Benefits
High Efficiency
o Resolution
o Speed
Scalability UPLC HPLC
7 chemistries: C18+
C18
C8
Phenyl
T3
HILIC
Shield RP 18

Where we were
14,150
4,000
8,000
12,000
16,000
0.00 0.25 0.50 0.75 1.00 1.25
Pla
tes (
4 s
igm
a)
Flow Rate (mL/min)
Since 2004, fully porous ACQUITY UPLC 1.7 m BEH C18
Has been our most efficient particle
Started us down the path of sub-2-m particles and the development
of UPLC Technology, which was needed to demonstrate its efficiency
ACQUITY UPLC 1.7 m BEH C18
2.1 x 50 mm column. A standard ACQUITY UPLC I-Class using 70% Acetonitrile in H2O at 30 C with 0.5 L injections from a 1 L FL injector

However, as of today Pla
tes (
4 s
igm
a)
2.1 x 50 mm column. A standard ACQUITY UPLC I-Class using 70% Acetonitrile in H2O at 30 C with 0.5 L injections from a 1 L FL injector
19,700
14,150
4,000
8,000
12,000
16,000
20,000
0.00 0.25 0.50 0.75 1.00 1.25
Flow Rate (mL/min)
39% higher efficiency
or up to 3x faster!
CORTECS UPLC 1.6 m C18+
ACQUITY UPLC 1.7 m BEH C18

Achieving Optimal Performance on CORTECS Solid-Core Columns
The Effect of System Dispersion on Column Performance
In 2004, key component of UPLC introduction was the relationship
between observed efficiency of small particle columns and the
dispersion of the system
As system dispersion decreases, observed efficiency of columns
increases.
In order to realize full potential of CORTECS Columns, and all small
particle columns, low-dispersions systems should be used.

Performance and Dispersion
True separation performance is governed by the system
dispersion paired with a flow rate range that yields the
highest possible effic

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