3.4.3.3 Equipment
• Chromatographic system for HPLC and 2D-LC. A prototype chromatographic
system for HT-2D-LC (Polymer Char, Valencia, Spain) was used for all
experiments. The system has an autosampler, two separate ovens, valves and
two pumps equipped with vacuum degassers (Agilent, Waldbronn, Germany).
The first oven is for thermostating the SEC column while the other one is used to
thermostat the HPLC column. The injector and a switching valve were housed in
the latter. An electronically controlled 8-port valve EC8W (VICI Valco
instruments, Houston, Texas, USA) equipped with two 100 μL loops was
employed for hyphenation of HT-HPLC and HT-SEC.
• HT-SEC. PL GPC 220 high-temperature chromatograph (Polymer Laboratories,
Church Stretton, UK) operating at 150
C equipped with a differential RI
detector, flow rate 1.0 mL/min, samples were dissolved at 160
C at a concentration of 1 mg/mL for 1–2 h, injection volume 200 μL, calibration with narrowly
distributed PS standards (Polymer Laboratories, Church Stretton, UK).
• TREF. Instrument developed and built in-house. For the fractionation, 3.0 g of
polymer, ca. 2.0 wt% Irganox 1010 (Ciba
® Speciality Chemicals, Switzerland)
and 300 mL of xylene were placed in a glass reactor and dissolved at 130 ºC. The
reactor was transferred to an oil bath maintained at 130 ºC. As a crystallization
support, preheated sea sand (white quartz, Aldrich, South Africa) was added to
the reactor. The reactor was cooled at the rate of 1 ºC/h to facilitate the controlled
crystallization of the polymer. A stainless steel column was packed with the
crystallized mixture and transferred to a modified GC oven for the elution step.
The temperature of the oven was increased at a steady rate while preheated
solvent (xylene) was pumped through the columns. Fractions were collected at
predetermined intervals, isolated by precipitation in acetone followed by drying
to a constant weight.
• LC-transform interface. LC-Transform series model 303 (Lab Connections,
Carrboro, USA) coupled to the HT-HPLC system. Samples were dissolved at
160
C in 1-decanol at a concentration of 1–1.2 mg/mL, with 110 μL of each
sample being injected. The HPLC column outlet was connected to the
LC-Transform interface through a heated transfer line set at 160
C. The
fractions were deposited by rotating a germanium disc (sample target in the
LC-Transform) at a speed of 10
per minute. The disc stage and nozzle
temperatures of the LC-Transform were set to 160
C.
• Columns. HT-2D-LC: Chromatograph 1: Hypercarb column (Thermo Scientific, Dreieich, Germany) packed with porous graphite particles with the following parameters: column size 100 mm  4.6 mm i.d., average particle size 5 μm,
surface area 120 m
2 /g, pore size 250 A ˚ . Chromatograph 2: PL Rapide H,
100 mm  10 mm i.d. (Polymer Laboratories, Church Stretton, England).
HT-SEC: Column set of three 300 mm  7.5 mm i.d. PLgel Olexis columns
together with a 50 mm  7.5 mm i.d. PLgel Olexis guard column (Polymer
Laboratories, Church Stretton, UK).
• Mobile phase. HT-2D-LC: Chromatograph 1: linear gradient 1-decanol to TCB
starting with 100 % of 1-decanol, flow rate 0.05 mL/min. Chromatograph 2:
3.4 Two-Dimensional Liquid Chromatography
131
• Chromatographic system for HPLC and 2D-LC. A prototype chromatographic
system for HT-2D-LC (Polymer Char, Valencia, Spain) was used for all
experiments. The system has an autosampler, two separate ovens, valves and
two pumps equipped with vacuum degassers (Agilent, Waldbronn, Germany).
The first oven is for thermostating the SEC column while the other one is used to
thermostat the HPLC column. The injector and a switching valve were housed in
the latter. An electronically controlled 8-port valve EC8W (VICI Valco
instruments, Houston, Texas, USA) equipped with two 100 μL loops was
employed for hyphenation of HT-HPLC and HT-SEC.
• HT-SEC. PL GPC 220 high-temperature chromatograph (Polymer Laboratories,
Church Stretton, UK) operating at 150
C equipped with a differential RI
detector, flow rate 1.0 mL/min, samples were dissolved at 160
C at a concentration of 1 mg/mL for 1–2 h, injection volume 200 μL, calibration with narrowly
distributed PS standards (Polymer Laboratories, Church Stretton, UK).
• TREF. Instrument developed and built in-house. For the fractionation, 3.0 g of
polymer, ca. 2.0 wt% Irganox 1010 (Ciba
® Speciality Chemicals, Switzerland)
and 300 mL of xylene were placed in a glass reactor and dissolved at 130 ºC. The
reactor was transferred to an oil bath maintained at 130 ºC. As a crystallization
support, preheated sea sand (white quartz, Aldrich, South Africa) was added to
the reactor. The reactor was cooled at the rate of 1 ºC/h to facilitate the controlled
crystallization of the polymer. A stainless steel column was packed with the
crystallized mixture and transferred to a modified GC oven for the elution step.
The temperature of the oven was increased at a steady rate while preheated
solvent (xylene) was pumped through the columns. Fractions were collected at
predetermined intervals, isolated by precipitation in acetone followed by drying
to a constant weight.
• LC-transform interface. LC-Transform series model 303 (Lab Connections,
Carrboro, USA) coupled to the HT-HPLC system. Samples were dissolved at
160
C in 1-decanol at a concentration of 1–1.2 mg/mL, with 110 μL of each
sample being injected. The HPLC column outlet was connected to the
LC-Transform interface through a heated transfer line set at 160
C. The
fractions were deposited by rotating a germanium disc (sample target in the
LC-Transform) at a speed of 10
per minute. The disc stage and nozzle
temperatures of the LC-Transform were set to 160
C.
• Columns. HT-2D-LC: Chromatograph 1: Hypercarb column (Thermo Scientific, Dreieich, Germany) packed with porous graphite particles with the following parameters: column size 100 mm  4.6 mm i.d., average particle size 5 μm,
surface area 120 m
2 /g, pore size 250 A ˚ . Chromatograph 2: PL Rapide H,
100 mm  10 mm i.d. (Polymer Laboratories, Church Stretton, England).
HT-SEC: Column set of three 300 mm  7.5 mm i.d. PLgel Olexis columns
together with a 50 mm  7.5 mm i.d. PLgel Olexis guard column (Polymer
Laboratories, Church Stretton, UK).
• Mobile phase. HT-2D-LC: Chromatograph 1: linear gradient 1-decanol to TCB
starting with 100 % of 1-decanol, flow rate 0.05 mL/min. Chromatograph 2:
3.4 Two-Dimensional Liquid Chromatography
131