Separation Acceleration through Temperature Increase

1) Retention drops to less than 50% going from the lowest to the highest temperature. 

3) The peaks appear much sharper at the elevated temperature, which translates into better resolution in spite of the markedly lower retention. 

The plot clearly demonstrates that all the hnes are almost parallel. This means that temperature has a marginal influence on selectivity, if at all. This is typical behavior for the separation of a homologous series in RP chromatography because the retention mechanism is uniform across all analytes. It can be concluded, therefore, that the temperature will not always help to aid optimization of selectivity in LC. 

It can be clearly seen that there is a steady increase in efficiency over a wide temperature range with an asymptote being reached at temperatures above 80 C. How can we explain this systematic increase in efficiency and how can we understand that in suddenly loses traction at higher temperature Before diving deeper into this discussion, it is necessary to assess the absolute level of theoretical plates in this example. With only 4200 plates under conditions slightly above room temperature this must be rated a very poor efficiency for a 250 mm long column packed with 5 pm material. It takes temperatures above 80 °C to jump over the 10 000 plate mark and make the column perform reasonably. The poor efficiency at lower temperature is a typical phenomenon on polymeric stationary phases as 

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Part of the coolant loop has two separate paths one path does not go through the heat exchanger and is used from the startup of the fuel cell system until the coolant temperature increases to a preset value (e.g., 60°C) to accelerate the rise of the coolant temperature the other path goes through the heat exchanger and is used when the coolant temperature reaches the preset value. Based on the stack needs, the coolant flow rate is adjusted by the coolant pump, and the heat that is dissipated out of the system enclosure is controlled by the fan mounted on the heat exchanger. 

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