Go With the Flow | 合法醫療器材資訊網

由SPMcCann著作—SuccessfulGCanalysisrequirescarefulcontrolofcarriergas.Here,weexplainhowtomeasureandcontrolflowrate,useconstantpressurevs.

Mobile phase flow is critically important, and must be carefully controlled. In this installment of “GC Connections,” we discuss carrier gas flow and its importance in successful gas chromatographic analysis. We will begin with a short review of fundamental theories showing why flow is important, and move into a discussion of how flow rate is measured and controlled on modern instruments. Finally, we will discuss the effect of flow-related parameters, including carrier gas choice, the difference between constant pressure and constant flow modes, and some new thinking about flow rate optimization. We conclude with some takeaways that should assist gas chromatographers with effective carrier gas management. 

When a sample is injected into a column in any mode of chromatography, its molecules spend time in one of two phases, the stationary phase or the mobile phase, as illustrated in the very fam...