Gas Samples

For accurate quantitative analysis gas samples are nearly always introduced by means of a valve fitted with an internal or external sample loop. Although the construction of gas-sampling valves takes a variety of forms, the principle of operation is common to all. In one configuration the gas passes through a loop ranging from approximately 0.1 to 10 mL in size while the carrier gas passes into the column. In the other configuration, the sample is isolated and the carrier gas stream sweeps the sample trapped in the loop onto the column. If care is taken to control the temperature and pressure of the gas, such valves offer very high reproducibility and all quantitative analysis can be performed by external calibration. They can also be readily automated for plant analysis. For further details see Gas analysis by gas chro-matography. Gas samples can be injected on to columns by means of gas-tight syringes but the precision is much poorer than that with loop valves and their use is not recommended for accurate quantitative analysis.

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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