COMPREHENSIVE TWO-DIMENSIONAL LIQUID CHROMATOGRAPHY WITH UHP SEC IN THE SECOND DIMENSION FOR SEPARATION OF INDUSTRIAL POLYMERSElena Uliyanchenko, 27 Sept. 2016

No. 1

OUTLINE

• Introduction to SABIC

• The need for multidimensional LC for polymers

• HPLC×SEC advantages and limitations

• UHPSEC in the second dimension: advantages and limitations

• Conclusions

No. 2

SABIC IN NUMBERS

1976 – SABIC founded

2015 (Forbes):

3rd largest global diversified chemical company

116th biggest public company in the world

91 B$ total assets

50 B$ annual revenue

40,000 employees

50 countries

65 world-class plants worldwide

5 key geographies with innovation hubs

150 new products each year

10,640 global patents

Pictures © SABIC

No. 3

CHEMICALS

POLYMERS

SPECIALTIESAGRI-

NUTRIENTS

METALS

SABIC’S STRATEGIC BUSINESS UNITS

• Olefins and gases

• Oxygenates

• Aromatics and chlor-alkali

• Glycols,…

• Polyolefins (PE, PP)

• Polycarbonate (PC)

• Polyvinyl chloride (PVC)

• Polystyrene (PS), …

• Polyphenylene ether

• Polyether imide

• PC copolymers

• Specialty film and sheet

• Long steel

• Flat steel

• Urea

• Ammonia

• Phosphates

No. 4

OUR GLOBAL TECHNOLOGY AND INNOVATION CENTRES

SABIC Global Headquarters (1)

Technology Centers (13)

Application Centers (4)

SABIC Corporate Research

and Innovation Center (1)

Distribution, Storage Facilities

and Logical Hubs (52)

International Subsidiaries and

Sales Offices (81)

Manufacturing and Compounding

Companies (62)

T&I location

STC-H

MTV

SLK

BOZ

STC-G

CTG

STC-R

STC-J

SPADC

MOKA

STC-SSTC-B

GLOBAL CHROMATOGRAPHY TEAM WITH > 40 MEMBERS WORLDWIDE

No. 5

POLYMER CHARACTERIZATION AT SABIC

Detailed structural

information

Optimization of production process

Development of materials with new properties

Improvement of material performance

Understanding of degradation mechanism

No. 6

CHARACTERIZATION OF POLYMER MOLECULAR DISTRIBUTIONS

Size-exclusion chromatography (SEC)

Hydrodynamic chromatography (HDC)

Gradient-polymer elution

chromatography (GPEC)

Molar-mass distribution

Chemical-composition distribution

Distribution of functionality

Molecular architecture

Etc.

Liquid chromatography at critical

conditions (LCCC)

Size-exclusion chromatography (SEC)

with multiple detectors

No. 7

ONE-DIMENSIONAL ANALYSIS OF PC/PC-COPOLYMER BLEND

min6 7 8 9 10 11

Norm.

0

20

40

60

80

100

120

DAD1 A, Sig=254,4 Ref=360,100 (AUG\SR 2015-08-12 11-33-29\091-0301.D)

DAD1 A, Sig=254,4 Ref=360,100 (AUG\SR 2015-08-12 11-33-29\092-0401.D)

DAD1 A, Sig=254,4 Ref=360,100 (AUG\SR 2015-08-12 11-33-29\093-0501.D)

Flow marker

BPA PC +

BPA PC copolymer

ONLY INFORMATION ON AVERAGE MW OF THE BLEND CAN BE OBTAINED BY SEC

min2 4 6 8 10 12 14

mAU

0

500

1000

1500

2000

2500

BPA PC

homopolymer

BPA PC copolymer

Size-exclusion separation Gradient liquid chromatography

separation

ONLY SEPARATION OF COMPONENTS BUT NO MW INFORMATION CAN BE

OBTAINED BY GPEC

No. 8

TWO-DIMENSIONAL LIQUID CHROMATOGRAPHY - INTRODUCTION

First-dimension separation

IUPAC:Two-dimensional chromatography - A procedure in which parts or all of the

separated sample components are subjected to additional separation steps.

This can be done e.g. by conducting a particular fraction eluting from the column into

another column (system) having different separation characteristics.

IUPAC Recommendations, PAC 65 (1993) 819

No. 9

First-dimension separation

IUPAC:Two-dimensional chromatography - A procedure in which parts or all of the

separated sample components are subjected to additional separation steps.

This can be done e.g. by conducting a particular fraction eluting from the column into

another column (system) having different separation characteristics.

IUPAC Recommendations, PAC 65 (1993) 819

TWO-DIMENSIONAL LIQUID CHROMATOGRAPHY - INTRODUCTION

No. 10

SINGLE-DIMENSIONAL SEPARATIONS ARE NOT ABLE TO REVEAL

DIFFERENCES

PS

PMMA

• Higher separation capacity (two-dimensional

space)

• Visual representation of 2D sample distribution

• Great amount of information in a single analysis

• Information on mutual dependence of two

distributions (for polymers)

TWO-DIMENSIONAL LIQUID CHROMATOGRAPHY - ADVANTAGES

No. 11

COMPREHENSIVE ON-LINE 2D LC

Position 1

Position 2

Advantages:

• Does not require intensive manual

work

• Relatively fast (within few hours)

• Automated data processing possible

• All information in a single analysis

(less prone to experimental errors)

Disadvantages:

• Experimental conditions in both

dimensions need to be adjusted

• Limited sample amount can be

injected

No. 12

2D LC APPLICATION TO STUDY MATERIAL DEGRADATION*

SBC

Mw=210 000 Da

SBC

Mw<110 000 Da

300RPM 1000RPM

*Data from Stephan Moyses (SABIC SLK, currently STC-H), ISPAC 2012 presentation

PPE

Mw=79 000 Da

PPE

Mw=94 000 Da

additive additive

No. 13

Analysis speed

Fast SEC in 2D: 2-3 min

Loop size: <200 µL

Flow rate in 1D: <100 µL/min

Loop 1

Inje

cto

r

Pump 1

Pu

mp

2

Detector

Loop 2

Column 1

Column 2

Waste

Resolution

Fast SEC in 2D: 2-3 min

Loop size: >200 µL

Flow rate in 1D: >100 µL/min

LIMITATIONS OF CONVENTIONAL 2D LC

Solvent consumption

Fast SEC in 2D at 5 mL/min

Analysis time: 3-4 hrs

Polymer peak width: >10 min

Good resolution of ca 5 fractions per peak

Ca. 1 L of (organic) solvent per analysis!

Analysis time: 1-2 hrs

Polymer peak width < 10 min

Low resolution of < 5 fractions per peak

No. 14

ULTRA-HIGH PRESSURE LC IN THE SECOND DIMENSION

m

pmp

D

udC

u

BDAdH

2

Fast SEC APC

Particle size 3 - 10 mm < 3 mm

Column dimensions 20x50 mm e.g. 4.6x150 mm

Max. pressure for the column 15 MPa >60 MPa

Extra-column variance ≥ 40 mL2 ca. 10 mL2

Column chemistry Polymer based Silica based

System flexibility Limited High

DivinylbenzeneStyrene

Ethylene bridges

No. 15

QUESTIONS/CONCERNS

• Are the molecular weights provided by SEC and APC comparable?

• Does switching of solvents influence separation repeatability in APC?

• Do we have higher polymer degradation in APC vs SEC?

• Does APC provide better trade-off between resolution and analysis time in 2D LC in

practice?

No. 16

QUESTIONS/CONCERNS

• Are the molecular weights provided by SEC and APC comparable?

• Does switching of solvents influence separation repeatability in APC?

• Do we have higher polymer degradation in APC vs SEC?

• Does APC provide better trade-off between resolution and analysis time in 2D LC in

practice?

No. 17

ARE THE MOLECULAR WEIGHT IN SEC AND APC COMPARABLE?

Poly-

mer

type

SEC (12 min) APC (6 min)Fast APC

(1 min)

Mn

(Da)

Mw

(Da)

PD Mn

(Da)

Mw

(Da)

PD Mn

(Da)

Mw

(Da)

PD

PC 14885 34138 2.29 14453 33672 2.29 14640 34399 2.35

PEI 19277 44892 2.33 20787 46124 2.22 18246 40545 2.22

PPE 22204 55680 2.51 16925 51390 3.04 21402 47558 3.04

PBT 38177 113660 2.98 36665 91133 2.49 38400 92067 2.49

The Mw and Mn data measured by SEC and APC are statistically different

APC provided stable response (RSD for Mw < 1%)

The data comparison was found to be suitable for 2D LC experiments

No. 18

QUESTIONS/CONCERNS

• Are the molecular weights provided by SEC and APC comparable?

• Does switching of solvents influence separation repeatability in APC?

• Do we have higher polymer degradation in APC vs SEC?

• Does APC provide better trade-off between resolution and analysis time in 2D LC in

practice?

No. 19

APC SYSTEM AND COLUMNS ROBUSTNESS

Solvents previously run

THFDCM

CHCl3 + DBA

CHCl3 + HFIP

100% HFIP

CHCl3 + HFIP, DCM

CHCl3 + HFIP + TFA

CHCl3 + DBA + butanol CHCl3 + HFIP + FA

CHCl3 + DBA

CHCl3 + HFIP + butanol

Mn (Da)Mw (Da)

35000

30000

25000

20000

15000

Da

ta

Boxplot of Mw (Da), Mn (Da) Recorded on Polycarbonate Sample Over 3 months (n=9)

RSD ~5%

Polycarbonate samples regularly

injected after measuring other

polymers at different column

temperatures and with different

solvents

No. 20

QUESTIONS/CONCERNS

• Are the molecular weights provided by SEC and APC comparable?

• Does switching of solvents influence separation repeatability in APC?

• Do we have higher polymer degradation in APC vs SEC?

• Does APC provide better trade-off between resolution and analysis time in 2D LC in

practice?

No. 21

POLYMER DEGRADATION

Study of PS degradation in UPLC

• Polymers were injected on UPLC column at different flow rates, collected and re-injected

• No significant degradation of PS with Mw up to ca 3 MDa at common conditions

• The onset of degradation was only slightly lower that reported for SEC

Minutes

1.06 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.38 1.42 1.46 1.50

Minutes

1.06 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.38 1.42 1.46 1.50

Minutes

1.06 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.38 1.42 1.46 1.50

Minutes

1.06 1.10 1.14 1.18 1.22 1.26 1.30 1.34 1.38 1.42 1.46 1.50

E. Uliyanchenko et al. J. Chromatogr. A 1218 (2011) 6039

Linear velocity > 7 mm/s

Onset of degradation

3 MDa PS, 2.1×100 mm UPLC column, 1.7 mm particles

Linear velocity < 7 mm/s

No degradation

NO DEGRADATION IS EXPECTED FOR MOST POLYMERS UP TO 2 MDa

(AVAILABLE SEPARATION RANGE OF APC)

No. 22

QUESTIONS/CONCERNS

• Are the molecular weights provided by SEC and APC comparable?

• Does switching of solvents influence separation repeatability in APC?

• Do we have higher polymer degradation in APC vs SEC?

• Does APC provide better trade-off between resolution and analysis time in 2D LC

in practice?

No. 23

Red

Std

Mw,

kDa

R

Yello

w S

td

Mw,

kDa

R

Gre

en

Std

Mw,

kDa

990 2.51 483 3.18 282 3.66

126 3.04 74.8 3.46 29.2 3.20

19.5 2.98 10.1 2.72 4.43 1.90

2.93 1.32 0.6

Columns: APC XT 125 + APC XT 450,

4.6 x 75 mm, 2.7 mm

Flow rate 2 ml/min, t0 = 1.25 min

Fast SEC APC

APC VS FAST SEC COLUMNS – PS STANDARDS

m in0.5 1 1.5 2 2.5 3

mAU

-2

0

2

4

6

8

10

12

D A D 1 B , S ig=272,4 R ef=360,100 (M A R \C A R O LE P S S P S S TD S 2016-03-31 15-16-41 \072-0202.D )

Column: 20 x 50 mm, SDV Linear M, 5 µm

Flow rate 5 mL/min, t0 = 2.7 min

990k

126k

19k3k

990k

126k

19k 3k

Red

Std

Mw,

kDa

R

Yello

w S

td

Mw,

kDa

R

Gre

en

Std

Mw,

kDa

990 1.24 483 1.12 282 1.29

126 1.20 74.8 1.34 29.2 1.18

19.5 1.18 10.1 1.26 4.43 1.05

2.93 1.32 0.6

Peak Resolution

No. 24

CHROMATOGRAPHIC RESOLUTION IN SEC

2212

12

4

ln

)(2

)/ln(

D

M

D

MMR

From: Striegel AM, Kirkland JJ, Yau WW, Bly DD (2009) Modern Size-Exclusion Liquid Chromatography.

2nd edn. John Wiley & Sons, New York

M1 and M2 – polymer molar masses

σ – peak standard deviation

D2 – slope of the calibration curve

No. 25

CALIBRATION CURVES FOR FAST SEC AND APC

Fast SEC column – mixed bed linear M: MW range 100-1000000

APC – combination of two single pore-size columns of 125 Å and 450 Å, MW range: 1000 - 400000

y = -6.594x + 9.354R² = 0.998

y = -5.546x + 8.441R² = 0.992

2.5

3

3.5

4

4.5

5

5.5

6

6.5

0.4 0.5 0.6 0.7 0.8 0.9 1

log M

w

tr (normalized)

PSS

APC

SELECTIVITY (D) IS ONLY SLIGHTLY BETTER FOR APC COLUMN

No. 26

PEAK STANDARD DEVIATION IN SEC

2222

columnextrachromPDIobserved

Band-broadening due to

polymer Mw distribution:

desired contribution

Band-broadening on

the chromatographic

column

Band-broadening in the

extra-column system

volume

Depends on

selectivityDepends on the stationary

phase, mobile phase, analyte

Depends on the

instrument

No. 27

H VS U CURVE FOR TOLUENE

Hobserved = Hchrom + Hextra-column

EXTRA-COLUMN CONTRIBUTION IS THE SAME AS THE SAME SYSTEM USED

APC CAN OFFER UP TO 50% IMPROVEMENT IN PLATE HEIGHT AT MUCH FASTER

ANALYSIS TIMES

0

20

40

60

80

100

120

140

160

0 2 4 6 8 10 12

H o

bserv

ed (mm

)

U, cm/min

0

20

40

60

80

100

120

140

160

0 0.2 0.4 0.6 0.8 1

H o

bserv

ed (mm

)Column length/min

Column pressure limit

APC

Fast SEC

APC

Fast SEC

No. 28

PLATE NUMBERS FOR TOLUENE

Flow rates,mL/min

N(5 cm column)

0.5 362

1 565

1.5 689

2 775

2.5 838

3 882

3.5 908

4 902

4.5 969

5 970

5.5 940

6 989

Flow rates, mL/min

N(15 cm column)

0.2 2828

0.4 4134

0.6 4906

0.8 5342

1 5639

1.2 5642

1.4 5370

1.6 5048

1.8 4809

2 4818

Fast SEC APC

No. 29

CALCULATED h vs. v CURVES FOR SEC

G. Stegeman, A. C. van Asten, J.C. Kraak, H. Poppe and R. Tijssen Anal. Chem, 66 (1994) 1147

The slope of h vs. v curves depends on the analyte / pore size ratio λ.

The chromatographic band broadening has maximum at λ ≈ 0.8

The pore size of the two columns in different!

pore

polymer

R

R

H. Engelhardt and G. Ahr J. Chromatogr. 282 (1983) 385

hS

EC

vSEC

λ>>1

λ=0

λ=0.2

λ=0.4

λ=0.6λ=0.8

Is the polymer behavior comparable to toluene?

No. 30

0

10

20

30

40

50

60

70

80

90

100

0 0.2 0.4 0.6 0.8 1

H(µ

m)

Column length/min

DEPENDENCE OF H VS U CURVE ON THE MOLECULAR WEIGHT

0

10

20

30

40

50

60

70

80

90

100

0 0.2 0.4 0.6 0.8 1

H(µ

m)

Column length/min

1.3 kDa

75 kDa

0

10

20

30

40

50

60

70

80

90

100

0 0.2 0.4 0.6 0.8 1

H(µ

m)

Column length/min

10 kDa

Depending on the Mw

fast SEC or APC show better

performance

Note: APC has somewhat better

selectivity and therefore higher PDI

contribution

APCFast SEC

APC

Fast SEC

APCFast SEC

No. 31

REAL CONDITIONS IN D2 – HIGH INJECTION VOLUME

For PSS column extra-column contribution in total peak widths is small and

does not significantly affect plate number

For APC column extra-column contribution in total peak widths is large

0

10

20

30

40

50

60

0.0 0.5 1.0 1.5 2.0 2.5

H o

bserv

ed (µm)

u (cm/min)

5uL

25uL

80uL

100uL

Fast SEC

1.3 kDa

0

10

20

30

40

50

60

70

0 2 4 6 8 10 12

H o

bserv

ed (µm)

u (cm/min)

5uL

25uL

80uL

APC

1.3 kDa

No. 32

SUB-CONCLUSIONS

• APC can offer a better trade-off between resolution and analysis time

• The benefits of APC over fast SEC decrease with increasing injection

volume in D2 and change with polymer molecular weight

• APC is especially advantages for high-resolution 2D LC separations

No. 33

HPLC×APC IN PRACTICE – HIGH-RESOLUTION SEPARATION OF SAN POLYMER

HPLC×SEC HPLC×APC

*HPLC×SEC chromatogram courtesy Stephan Moyses (SABIC SLK, currently STC-H)

No. 34

HPLC×APC IN PRACTICE – ANALYSIS OF PC COPOLYMER BLEND

PC

homopolymer

1OH

2OHcopolymer oligomers

PC copolymer

GPEC – separation based on chemical composition

GP

C –

sep

ara

tio

n b

ased

on

mo

lecu

lar

weig

ht

Fully end-capped

1.5 hrs

30 sec

PC-OLIGOMERS ARE WELL-RESOLVED

No. 35

30 min

HPLC×APC AND HPLC×SEC IN PRACTICE – ANALYSIS OF PC COPOLYMER BLEND

1.5 hrs

HPLC×SEC

HPLC×APC

PC

homopolymerPC copolymer

oligomers

PC

homopolymerPC copolymer

No. 36

Advantages:

• Legacy stationary phase, minimal

differences in Mw expected compared to

“normal” SEC

• Available in broad pore size range

• Less sensitive to high injection volumes

in D2

Disadvantages:

• High solvent consumption

• Short columns – low plate number

• Difficult to exchange solvent

• Lower sensitivity due to high dilution

Advantages:

• Fast separations (e.g. down to 1 min)

• Low solvent consumption

• Higher sensitivity due to lower dilution

• Flexible: solvent can be easily replaced

Disadvantages:

• Mw data can differ from legacy SEC

methods

• Limited pore sizes available, no linear

columns

• Sensitive to high injection volumes in D2

Fast SEC APC

CONCLUSIONS

No. 37

ACKNOWLEDGEMENTS

• Stijn Rommens (SABIC)

• Christian Wold (SABIC)

• Stephan Moyses (SABIC)

• Carole Reymond (CPE Lyon)

• Charlotte Pourtier (Montpellier Univ.)

• WATERS and PSS

No. 38

No. 39

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