Investigation and Comparison of 5 % Diphenyl – 95 % Dimethyl Polysiloxane Capillary Columns

Abstract

In gas chromatography, for the analysis, the most important thing is the well-chosen column. After having decided about which stationary phase is the best for our measurement and we know the length, the inner diameter and film thickness, we can buy the column from a lot of manufacturers. The products of these manufacturers’ look similar to each other, but they are different, because of the different manufacturing technologies. These differences could have significant influence on the separation. It is so important to compare the „same” columns, despite the manufacturers’ efforts to produce the best quality columns.5 % diphenyl – 95 % dimethyl polysiloxane stationary phase is widely used. Its slight polarity makes it able to determine very different compounds from the alkanes, through volatiles, drugs, fatty acid methyl esters, amines or phenols.In our work, we tested 5 % diphenyl – 95 % dimethyl polysiloxane stationary phase columns with an 8-component mixture. These columns were from different manufacturers. During isothermal conditions, we determined the height equivalent of theoretical plates on 8 linear velocity level. We represented these parameters as the function of linear velocity. With a constant linear velocity, we measured the excess sorption enthalpy and entropy. From the chromatograms we spotted differences in the retention and in resolution, which is important if we use the column for volatiles or for complex samples. With these parameters we can show many differences between the columns. These parameters have significant influence when we want to use our column for a given task.

Comparison of 624-type Capillary Columns

“…With other linear velocity values applied, no coelution occurred on any column. Valeric acid (10) did not appear on the CP-Select 624 b column.…”

“…In our previous study, we compared equivalent 5% diphenyl -95% dimethyl polysiloxane capillary columns reaching the conclusion that they show differences in enthalpy, entropy, retention, peak shape, and efficiency for the investigated compounds [10]. In addition, in our present study, we want to show how the column manufacturer and prelife affect the detector response signal, i.e., the effective carbon number, and thus the extent to which the lower limit of quantitation is influenced.…”

Hydroxyl-functionalized pillar[5]arene with high separation performance for gas chromatography

“…[7][8][9][10][11][12] However, commercialized polysiloxane (PDMS), polyethylene glycols (PEG) and ionic liquids (ILs) columns tend to show partial overlapped or coeluted peaks when separating challenging isomers, degrading the accuracy of the analysis. [13][14][15][16][17] Sample derivatization and inactivation are currently applied to solve the above problem, which requires additional procedures but results in extra expenditure and low efficiency. [18][19][20] In this case, the development of new stationary phases with high selectivity and inertness is of great value in order to obtain a high resolution of the challenging analytes and critical pairs.…”

Analysis and Comparison of Gas Chromatographic Columns with Polyethylene Glycol Stationary Phase

“…In our previous study [15] we compared 5% diphenyl 95% dimethyl polysiloxane columns from different manufacturers. We compared retention, peak shape, resolution, efficiency, and sorption enthalpies and entropies to find out which column for what purpose is suggested.…”