The Effect of Draw-Out Lens Diameter on Sensitivity of GC–MS Analysis
Gas chromatography–mass spectrometry (GC–MS) allows isolation and identification of individual analytes within a complex mixture. Helium has traditionally been the first-choice carrier gas, owing to its inertness, performance, and relatively cheap price. Since 2001, however, helium has become increasingly expensive with a reported global increase in price of 500% between 2001 and 2016 (1). In 2012–2013, the global helium shortage increased the number of GC users switching to alternative carrier gases and improved the availability of information on their use.