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SGE is in the business of developingand producing GC capillary columns for a  long time. Back in 1959, Ernest Dawes, the founder of SGE started with the production of glass capillary columns. It is with the application of the knowledge of chromatography along with the latest glass technology, polymer synthesis, surface chemistry and production processes which lead to the expertise in this field.

SGE became the only capillary chromatography company that excels in the development and synthesize of polymers and offers different GC stationary phases. The company gets the credit to initiate many new innovations in this field like the silarylene phases and carborane phases in 1987 and SolGel in 1999. There is a detailed description of the working of polymers on pages 76 to 80.

SGE, the manufacturer of GC capillary columns is well-known in this industry for the use of latest technology to build the capacity of undertaking the whole procedure of producing the finest capillary columns. Right from the start till the end, the production process is done with expert guidance to even manufacture the fused silica capillary tubing. It is this competence due to which the company is ahead in the task of producing the best capillary columns with high-quality.

SGE puts to use the following technological updates for preparation of GC capillary column:

  • The extraction of the precision fused silica capillary tubing.
  • Advancement of specialty polymer stationary phases with the development and synthesis processes.
  • The process for making the fused silica surface compatible with the cross-linked stationary phase with the chemical treatment.
  • The process of coating and cross-linking the polymer stationary phase.
  • To test the quality of the manufactured capillary column with set high-standards.

Fused Silica

SGE carries out the process of manufacturing of the fused silica with a series of high-level extracting towers. The whole process is carried out under prescribed conditions and even specific loops are created for making automatic adjustments in the conditions. The capillaries are developed strongly under such strict control from all aspects and it can easily be verified with the help of stress-proof testing. So, SGE feels proud in announcing the production of fused silica along with the high-quality of the GC capillary columns.

The company assures the purity of fused silica with the best production process that avoids any impurities like metal oxides which are mostly found in the traditional glasses. The selection of the FST is dependent on its application. Usually, SGE produces two types of FST coating, one is polyimide where the maximum temperature should be 400 °C and the other is aluminum where the maximum temperature should be 480 °C. The phase determines the usage of the capillary columns produced by SGE but mostly the ideal temperature is 400 °C.

Stationary Phase Polymer

The creation of the phase synthesis by SGE is done in such a way that the capillary columns are easily washed without getting contaminated during the process. It may be possible that the performance of the capillary column gets deteriorated with the longtime use. The performance can be easily restored by washing the capillary column with a suitable solvent that can remove the contamination too. The detailed description of the same is available on page 196.

Rigorous Performance Testing

The various types of the capillary column used for different purposes are tested on the basis of their application in order to check the standard. The regular capillary columns are tested and verified with the standards for difficult to chromatograph compounds to know whether the performance is stable at each level and condition. One such example is the test of SGE’s non-polar phase BPX5 with certain active probes and with sufficient time period to check the standard met by it. There is no separate rage of capillary columns to meet the high standards as all the GC capillary columns are of high-quality that can be used for achieving various performance levels.

Retention Time and Consistency

It is due to the expertise in the capillary column fabrication process that SGE is able to achieve the remarkable features for each produced column. Each SGE column exhibits the same results even with the change of the method or application.

Thermal Stability

The common issue with the GC capillary columns is the undue noisy baseline signals which are observed due to the failure of stationary phase at elevated temperatures. It also prevents the sensitivity of the analysis. Even, the latest technology cannot overcome this issue. Yet, the main achievement of SGE is the introduction of the silarylene in the year 1987. Silphenylene phases replace some of the oxygen atoms in the backbone of the siloxane polymer with aromatic groups. There is a wide range of polarities and selectivities which is available due to the improved thermal stability for GC phases. The SGE capillary columns fulfill the standard requirements thoroughly. Testing is done at the maximum operating temperature to check the bleeding performance of the GC capillary columns which means that it will be measured and quantified with the indicator like “nanograms of siloxane per second”.

The accuracy of the calculation of bleed for the capillary column with nanograms of siloxame per second method is quite high rather than the picoamp FID signal. The main reason that Picoamp signal is not the perfect method is the unreliability due to the dependence on indicator and change in the condition. In order to get more excellent results, SGE performs the bleed measurement on FID.

A detailed SGE GC Capillary Column Performance Report is presented below:

GC Capillary Columns Polarity Scale

The proper designing by SGE of the various product ranges strive excellence in meeting the standards set by the industry in synthesizing various elements. The use is quite easy for the chromatographer as the products fulfill the objective for the GC stationary phase when used for different compounds.

The chromatographers would definitely achieve the target after considering the importance of separation each time. The resultant effect can be checked with the formula R where the variables like capillary column efficiency, retention, and selectivity are influenced.

One of the ways to verify the equation given above is the impact on the capillary column efficiency, the physical dimensions, and the phase chemistry. There is a need for the concentration on the flow rates and temperatures along with the effect on the relative retention time for the availability of peak shapes and nice separations. It is the final result at the end of chromatography which is achieved with the interaction with the phase.

Stationary Phase Polarity

The phase chemistry can go well with the understanding of polarity along with the linear polarity scale which fits the phase properly. It is the various interactions which are dependent on the type of functionality of the GC stationary phase polymer. SGE gets the accurate measurement from the stationary phases with the scaled representation which is dependent on the chemical constituent that is being measured. It is the scale that gives a clear idea of the relative ability of each phase during the interaction with the various types of analytes.

A 3D Phase Polarity diagram is presented below. It is clearly understood that the scales can be easily measured by quality rather than the quantity which is evident from various experiments conducted for the study of retention of the analytes with the change in the stationary phase. The primary motive behind this was to evolve a three dimensional representation when each of the phase fits the classic bonding mechanisms namely three of them being ‘Van der Waals’, H-bonding and p-bonding.

Bonding Mechanisms

The bonding mechanism of Van der Waals is the formation of the electrostatic attraction which is obvious from the temporary dipoles. This evidently forms a weak interaction. The right way to get the relative contribution is from the dimethylsiloxanes which are a nonpolar phase.

The bonding mechanism of hydrogen is the resultant of the attraction of the charges of hydrogen, both, positive and negative with the non-bonding pairs of electrons. Here is when the water molecules are held together as a liquid.

The bonding mechanism related to p-bonding is the accurate association with the compounds of the aromatic class like benzene rings. It is the attraction of the molecules loosely held in the donut-shaped electronic charges. There is a perpendicular relation of the p-bond in benzene with the benzene ring bonds which makes the interaction quite easy provided the molecules in that shape do not form steric hindrance.

It becomes easy to modify the functions of the stationary phases which comprise of basic polymer units with the addition of the different moieties at the time of synthesis. The addition can be done in varying amounts so that each function creates a different concentration.

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