Download Chromatography - Aston University

Aston University EBRI
Chromatography
Chromatography is term used for a broad range of physical methods used for separation and
analysis of complex mixtures which involves a sample being dissolved in a mobile and forced
through a stationary phase in which different compounds get separated and then will be detected
by detectors. Based on the form of the mobile phase, chromatography is divided into two
categories:
Gas chromatography
Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for
separating and analysing compounds that can be vaporized without decomposition. EBRI is
equipped with 12 GCs including one GC-Mass spectrometry manufactured by Agilent, Bruker and
Shimadzu.
Liquid chromatography
High performance liquid chromatography (HPLC) is a powerful tool to separate, identify & quantify
components dissolved in a liquid mixture with a high analytical resolution. Currently in EBRI, there
are two Agilent 1260 Infinity HPLC systems equipped with refractive index, diode array and
fluorescence detectors and a range of different columns including Hi-Plex H and Hi-Plex Ca (Duo)
for analysis of monosaccharide, oligosaccharide mixtures and organic acids.
Radleys Carousel Reaction Stations and jacketed reactors
Instead of using the old-fashioned oil-bath systems, Radleys Carousels enable researchers to
carry out up to 5 reactions in parallel in identical conditions with precise temperature and stirring
rate control. At EBRI, several Radleys Carousel Reaction Stations are being utilised for catalyst
preparation as well as for performing catalytic reactions. Also there are two jacketed reaction
systems for large scale (up to 5 litres) catalyst synthesis; equipped with overhead stirrers and
temperature controllers.
N2 porosimetry
Nitrogen porosimetry is an analytical technique which can give information about physical and
structural properties of solid materials such as surface area, pore diameter, meso- and micropore
volume, total pore volume, etc. There are 4 Quantachrome Nova N2 porosimetry instruments at
EBRI.
High pressure-temperature reactors
Some chemical reactions require high gas pressure and/or temperatures. In order to be able to
carry out research on such reactions, EBRI is equipped with 7 Parr compact reactors which can
go to temperatures and pressures as high as 350°C and 100 bar respectively.
Liquid phase flow reactors
Flow reactors provide an excellent link between the laboratory and much larger industrial scale
processes. In this mode, a wide variety of parameters can be screened in a relatively short time
period, such as pressure, temperature, solvents and substrate concentration, yielding greater
understanding of catalyst properties and behaviour prior to scale-up. EBRI is equipped with a
commercially available “Uniqsis Flowsynth reactor.”
ATR-IR spectroscopy (Attenuated Total Reflectance – Infra-red)
ATR-IR is an analytical technique which can be used to probe the species present on the surface
of a thin film of sample material. Information can be determined about identity and type of surface
sites present; however the real power of this technique lies in the ability to determine the mode of
interaction between catalyst and substrate under pseudo-operando conditions. EBRI has a
Thermo Scientific Nicolet iS50 spectrometer, equipped with a Pike environmental in-situ cell.
DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy)
DRIFTS utilises Infra-red light to ascertain the surface properties of catalytic materials. Adsorption
of probe compounds (such as pyridine or carbon monoxide) can permit the elucidation of surface
sites and type, providing a more in-depth picture of catalyst structure. EBRI has two Thermo
Scientific Nicolet iS50 spectrometers fitted for DRIFTS mode.
Chemisorption
Chemisorption arises due to chemical interactions (bonds) between an adsorbate and a surface,
with such specificity imparting selectivity into the measurement which thus allows evaluation of
active catalytic species. Quantitative titrations allow the number surface sites present to be
determined, with application including transition metal sites, metal oxides and acid/base sites,
whilst temperature programmed desorption, or reaction under oxidising or reducing conditions,
allows further insight with elucidation into active site strength and/or morphology.
TGA-MS
Thermogravimetric analysis monitors the evolution of physical and chemical properties of
materials as a function of temperature, via associated mass losses and heat flow (endothermic
or exothermic processes), with application including oxidation, reduction, desorption and
reactions under appropriate gas flows. The coupling of mass spectrometry into the set-up, via
the gas stream exhaust, facilitates qualitative analysis of both reactive gas consumption/product
formation and chemical species evolved from the material under analysis.
DRUVS
The measurement geometry utilised in diffuse reflectance ultraviolet–visible spectroscopy
imparts surface sensitivity, with the configuration also facilitating in-situ/operando
measurements of solid materials under flowing reactive gases and/or temperature. The
technique is commonly applied to transition metal compounds, metal nanoparticles and
photocatalysts.
X-ray photoelectron spectrometer
The Kratos Axis HSi photoelectron spectrometer is a highly advanced surface technique, used
in EBRI for the characterisation of nanostructural calatytic materials. It also has in-situ
capabilities, with a heating and cooling cell within the analysis chamber, for studying changes to
oxidation states or surface elemental concentrations in non-ambient conditions, as well as a
high pressure heated treatment chamber, for following chemical reaction pathways using a
gas/vapour dosing system. The instrument has 3 x-ray sources, allowing for the removal of
interfering Auger transitions, as well as advanced techniques, such as depth profiling.
Powder X-ray diffractometer
The Bruker d8 advance powder XRD is a high throughput diffractometer, for the analysis of
crystallinity and phase determination of powder samples, such as metal nanoparticles or highly
ordered mesoporous materials. 2θ values of 0.45° to 10° can be obtained through use of the low
angle set-up, or 10° to 120° using the standard Bragg-Bentano geometry. The instrument is also
capable of utilising an Anton-Paar XRK-900 high pressure cell, allowing for analysis under nonambient pressures and temperatures, and the instrument is connected to a variety of gases and
mass flow controllers. Advanced techniques such as reflectivity or offset 2θ scans are also
made possible using this cell.
Inductively coupled plasma optical emission spectrometer
Our Thermo iCAP 7000 ICP-OES is a tool for quantitative elemental analysis of solutions or,
through utilisation of our microwave digestion techniques, solid samples. With up to sub ppb
detection limits possible for a large amount of elements, this technique is an incredibly useful
tool for ion detection (for example, the study of the kinetics of dissolution).
Flash 2000 elemental analyser
The Thermo FLASH 2000 elemental analyser is a fast, easy and accurate method for the
determination of organic contents in any sample (e.g. Biomass). The instrument is set up for the
simultaneous analysis of carbon, hydrogen, nitrogen and sulphur, and analysis of solid or liquid
samples is possible.
Photocatalytic reactors
The photocatalytic reactors in EBRI are set-up to follow reactions catalysed by semi-conductive
photoactive materials under UV light. Both monochromated LEDs (365 nm) and nonmonochromated UV lamps are set up in separate units, each with a quartz reactor. Used in
combination with gas chromatography, HPLC or UV-Vis spectroscopy, we are able to follow
photodegradation or evolution kinetics of both UV-active and smaller molecules with ease.