National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
J Chromatogr A. 2012 Jan 13;1220:75-81. doi: 10.1016/j.chroma.2011.11.051. Epub 2011 Dec 2.
Excess volume isotherms of acetonitrile and methanol sorbed on a C(18) BEH UHPLC packing were determined over a range of pressure, temperature, flow rate and eluent composition. The isotherm measurements were carried out by two independent experimental methods, viz., concentration pulse and tracer pulse chromatographies. Isotherms were measured with both experimental techniques at 30, 45 and 60 °C. The excess isotherms increased with decreasing temperature although the variations were relatively small. Direct comparison of the two experimental techniques showed that the measured void volumes were identical within experimental error. The measured excess volumes by both techniques were comparable with the concentration pulse experiments producing slightly higher excess volume data with highly aqueous eluents. Both experimental techniques show some variations of the retention volumes with sample volume, sample composition, flow rate and column inlet pressure. The results confirmed the validity of both concentration and tracer pulse chromatographies for the determination of column void volumes and the excess volume of eluent taken up by UHPLC packings.
在压力、温度、流速和洗脱剂组成的范围内，测定了乙腈和甲醇在 C(18) BEH UHPLC 填料上吸附的过剩体积等温线。等温线测量通过两种独立的实验方法进行，即浓度脉冲色谱法和示踪脉冲色谱法。在 30、45 和 60°C 下，用两种实验技术测量了等温线。尽管变化相对较小，但随着温度的降低，过剩等温线增加。两种实验技术的直接比较表明，在实验误差范围内，测量的空隙体积是相同的。两种技术测量的过剩体积与浓度脉冲实验相当，在高水相洗脱剂中产生稍高的过剩体积数据。两种实验技术都显示出保留体积随样品体积、样品组成、流速和柱入口压力的一些变化。结果证实了浓度和示踪脉冲色谱法在测定柱空隙体积和 UHPLC 填料所吸收的洗脱剂过剩体积方面的有效性。
