Hand-Portable Gradient Capillary Liquid Chromatography Pumping System

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• 作者：Sonika Sharma ; Alex Plistil ; Hal E. Barnett ; H. Dennis Tolley ; Paul B. Farnsworth ; Stanley D. Stearns ; Milton L. Lee
• 刊名：Analytical Chemistry
• 出版年：2015
• 出版时间：October 20, 2015
• 年：2015
• 卷：87
• 期：20
• 页码：10457-10461
• 全文大小：261K
• ISSN：1520-6882

文摘

In this work, a novel splitless nanoflow gradient generator integrated with a stop-flow injector was developed and evaluated using an on-column UV-absorption detector. The gradient pumping system consisted of two nanoflow pumps controlled by micro stepper motors, a mixer connected to a serpentine tube, and a high-pressure valve. The gradient system weighed only 4 kg (9 lbs) and could generate up to 55 MPa (8000 psi) pressure. The system could operate using a 24 V DC battery and required 1.2 A for operation. The total volume capacity of the pump was 74 渭L, and a sample volume of 60 nL could be injected. The system provided accurate nanoflow rates as low as 10 nL/min without employing a splitter, making it ideal for capillary column use. The gradient dwell volume was calculated to be 1.3 渭L, which created a delay of approximately 4 min with a typical flow rate of 350 nL/min. Gradient performance was evaluated for gradient step accuracy, and excellent reproducibility was obtained in day-to-day experiments (RSD < 1.2%, n = 4). Linear gradient reproducibility was tested by separating a three-component pesticide mixture on a poly(ethylene glycol) diacrylate (PEGDA) monolithic column. The retention time reproducibility was very good in run-to-run experiments (RSD < 1.42%, n = 4). Finally, excellent separation of five phenols was demonstrated using the nanoflow gradient system.