Carrier

Three carrier gases are used in preparative GC - hydrogen, helium or nitrogen. The influence of the chemical nature of the carrier gas on the selectivity is negligible, so the choice will depend on the physical properties of the gases and on the environment.

Two features influence the separation performance. Viscosity governs the pressure drop in the column and consequently the possible speed of the carrier gas and diffusivity influences the mass transfer of the sample in the column and consequently the efficiency.

Whenever possible, hydrogen is chosen because of its low viscosity, high diffusion coefficient and low cost. If, for safety reasons, it is not possible to use hydrogen then helium is the second choice.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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