Liu M K, Williams P S, Myers M N, Giddings J C
Department of Chemistry, University of Utah, Salt Lake City 84112.
Anal Chem. 1991 Oct 1;63(19):2115-22. doi: 10.1021/ac00019a010.
Two means are described for achieving hydrodynamic relaxation and thus avoiding the stopflow injection procedure in field-flow fractionation (FFF): split flow injection and frit inlet injection. The advantages, disadvantages, and the theoretical basis of these procedures are discussed. Incremental band broadening due to the final relaxation step is examined theoretically and shown to be negligible when the flow rate of the sample inlet substream is small compared to the total channel flow rate. The optimization of the sample inlet flow rate is discussed. Experimental results for both injection procedures are reported for flow/steric (or hyperlayer) FFF applied to latex standards, confirming the expected trends. However, closer examination shows that the observed incremental band broadening associated with hydrodynamic relaxation is somewhat larger than the value predicted.
文中描述了两种实现流体动力学弛豫从而避免场流分级（FFF）中停流进样程序的方法：分流进样和烧结滤片进样。讨论了这些程序的优缺点及理论基础。从理论上研究了由于最终弛豫步骤导致的增量谱带展宽，结果表明，当样品进样子流的流速与总通道流速相比很小时，该展宽可忽略不计。还讨论了样品进样流速的优化问题。报告了将流动/空间（或超层）FFF应用于乳胶标准品时两种进样程序的实验结果，证实了预期趋势。然而，进一步研究表明，观察到的与流体动力学弛豫相关的增量谱带展宽比预测值略大。
