Gas sampling valves with an external sampling loop with a fixed volume have become a classical technique for gas phase injection in gas chromatography. Commercially available gas sampling bags made of fluorinated polymers have gained popularity in environmental applications such as transporting and preparing calibration standards for direct reading instrument and gas chromatographs. This study present an underlying principle for a potential bias and thereby propose a good practice for typical sample bag analysis by gas sampling loop injectors. Results from a case study is demonstrated on occurrences of possible bias differences in response peak for an inert component (e.g. CH4) of the identical concentration even with the identical balance gas (e.g. N2) between in the bag and in the highly pressurized cylinder used as a standard, depending on how to control gas pressure inside of the sampling loop. Performance test results are presented from the automated, consecutive analysis of sampling bags together with cylinder gas standards.
Namgoo Kang earned a B.S. degree in Agricultural Chemistry and a M.S. degree in Environmental Management from Seoul National University, Seoul, Korea. He earned a Ph.D. degree in Environmental Engineering from Purdue University, Lafayette, Indiana, USA. He was a Post-doctoral Research Associate at Texas Tech University, Texas, USA. He is currently a Principal Research Scientist and the leader of Hydrocarbons and Energy Gas Metrology at Korea Research Institute of Standards and Science. He is also a Professor in Science of Measurement at University of Science and Technology, teaching a coursework (Statistical Data Analysis) for graduate students. He is currently a Principal Investigator of Cooperative Research Program for Agriculture Science & Technology Development (PJ012489022017) funded by Rural Development Administration, Korea and a researcher in Atmospheric Environment Measurement Standards Technology Development (17011010) funded by Korea Research Institute of Standards and Science.