|about silica products carbon fibre products fine chemicals catalogues latest news contact|
Silica Gels for Column Chromatography
Silica gel is used in organic chemistry for the purification and isolation of synthetic compounds (i.e. post-reaction “harvesting” of chemical products).
The high purity, low level of fines, low water content and neutral pH of Material Harvest® silica gels provide an ideal stationary phase for optimum and reproducible purification. Our column chromatography silica gel 60 is available in a variety of particle size or "mesh" grades, including mesh 70 – 230 (63 – 200 µm) and mesh 230 – 400 (40 – 63 µm). Please refer to our lecture notes below for information on the significance of these figures.
Our multi-kg drums are unique, offering air/water-tight seals for long-term preservation of quality. If used correctly, these drums may protect your silica from floods or chemical vapours.
Our “academic grade” Silica Gel 60
The number “60” in “Silica Gel 60” indicates that the average pore diameter of the silica particles is 60 Å. This type of normal phase column chromatography silica gel is the most common in university and industrial research laboratories.
In terms of the particle size distribution, the most popular grades of silica gel 60 are:
We offer academic discounts to universities and consumption-based discounts to industrial laboratories - please do not hesitate to contact us for more detail.
Other grades of Material Harvest® Silica (including Silica Gel 40 and 90)
The following normal phase chromatography silica gels can be manufactured on demand. We can also customise silica – the pore size, particle size, pore volume, surface area, pH and water content can be altered to suite your requirements or intended application.
Please contact us to discuss your requirements or to request a quote.
Notes on Normal Phase Column Chromatography
Column chromatography is a purification technique used in organic chemistry and synthesis. It can potentially isolate a desired compound from a mixture of unwanted substances – for example the product of a chemical reaction may be separated from its crude mixture by use of column chromatography.
Column chromatography utilizes a stationary phase, otherwise known as a sorbent or an adsorbent, which is normally packed in a glass column. Common examples of stationary phases include silica gel and alumina. The mixture of compounds is applied at the top of the column and a solvent or solvent mixture, known as the “eluent” or “mobile phase”, is allowed to flow through the silica gel or alumina.
If the eluent flows down the chromatography column by gravity, the technique is referred to as “gravity column chromatography”. If positive pressure is used to force the eluent down the column at a faster rate, the technique is referred to as “flash column chromatography”.
Each component of the mixture will exhibit a different interaction (or degree of interaction) with the stationary and mobile phases; this interaction will largely depend on the chemical structure and geometry of the molecule concerned. Thus, the components of a mixture will be carried down the column at variable rates and separation may be achieved.
In normal phase chromatography, a polar sorbent such as silica gel is used and the less polar molecules are eluted first (polar molecules experience a greater degree of retention than non-polar molecules do).
Silica gel is one of the most commonly used stationary phases in normal phase column chromatography. It is available in a variety of shapes and sizes, though the most common grades in organic chemistry are mesh 70 – 230 (63 – 200 µm) for gravity column chromatography and mesh 230 – 400 (40 – 63 µm) for flash column chromatography. The number “60” in “Silica Gel 60” indicates that the pore diameter of the silica particles is 60 Å.
If you would like to receive more information please email email@example.com