Anspach Jason A, Maloney Todd D, Brice Richard W, Colón Luis A
Department of Chemistry, University at Buffalo, State University of New York, Natural Science Complex, 14260, USA.
Anal Chem. 2005 Nov 15;77(22):7489-94. doi: 10.1021/ac051213f.
The increased interest in HPLC at elevated pressures, beyond the conventional 6000 psi (400 bar), has created a demand for injection systems capable of withstanding pressures beyond the 20,000 psi (1380 bar). To achieve high-resolution separations, an appropriate length of columns packed with sub 2-microm packing materials, a 30,000-40,000 psi (2070-2760 bar) pressure range is desirable. A new air-actuated needle valve injection system rated to withstand pressures of up to 40,000 psi (2760 bar) has been evaluated. Under isocratic chromatographic conditions, injecting 200 nL and operated at approximately 20,000 psi (1380 bar), the system showed a peak area reproducibility of approximately 2.5% RSD, contrasting the 5% RSD of a pressured-balanced injection system operated under similar conditions. Programmed for partial loop injections using injection times of 300-700 ms (injection volumes in the range of 1-2.5 microL) and operated at pressures close to 30,000 psi (2070 bar), the reproducibility in peak area for the amounts injected was approximately 1.5% RSD or lower, while an injection time of 100 ms resulted in a reproducibility of 3-4% RSD. The new injection system did not show any significant carryover, and after thousands of injections, the system has not shown sign of wear, loss of pressure during injection, or loss in chromatographic performance.
对超高压高效液相色谱（HPLC）的兴趣日益增加，压力超过传统的6000 psi（400 bar），这就产生了对能够承受超过20,000 psi（1380 bar）压力的进样系统的需求。为了实现高分辨率分离，使用填充有亚2微米填料的适当长度的色谱柱，理想的压力范围是30,000 - 40,000 psi（2070 - 2760 bar）。一种新的气动针阀进样系统，额定压力高达40,000 psi（2760 bar），已经经过评估。在等度色谱条件下，进样200 nL并在约20,000 psi（1380 bar）下运行，该系统的峰面积重现性约为2.5% RSD，相比之下，在类似条件下运行的压力平衡进样系统的RSD为5%。使用300 - 700 ms的进样时间（进样体积在1 - 2.5微升范围内）进行部分定量环进样编程，并在接近30,000 psi（2070 bar）的压力下运行，进样量的峰面积重现性约为1.5% RSD或更低，而100 ms的进样时间导致的重现性为3 - 4% RSD。新的进样系统没有显示出任何明显的残留，经过数千次进样后，该系统没有显示出磨损迹象、进样过程中的压力损失或色谱性能损失。
