Department of Chemistry, Vanderbilt University, Station B 351822, Nashville, Tennessee 37235, United States.
Anal Chem. 2012 Oct 16;84(20):8467-74. doi: 10.1021/ac3021032. Epub 2012 Sep 25.
Current desalination techniques for mass spectrometry-based protocols are problematic for performing temporal response studies where increased temporal resolution requires small samples and faster sampling frequencies, which greatly increases the number of samples and sample preparation time. These challenges are pertinent to cellular dynamics experiments, where it is important to sample the biological system frequently and with as little sample waste as possible. To address these needs, we present a dual-column online solid phase extraction (SPE) approach capable of preconcentrating and preparing a constantly perfusing sample stream, with minimal to no sample loss. This strategy is evaluated for use in microfluidic bioreactor studies specifically aimed at characterizing suitable sample flow rates, temporal resolving power, and analyte concentrations. In this work, we demonstrate that this strategy may be used for flow rates as low as 500 nL/min, with temporal resolving power on the order of 3 min, with analyte loadings ranging from femtomoles to picomoles for metabolites. Under these conditions, recoveries of ca. 80% are obtained even at femtomole loadings.
目前基于质谱的方案的脱盐技术在进行时间响应研究时存在问题，因为增加时间分辨率需要小样本和更快的采样频率，这大大增加了样本数量和样本制备时间。这些挑战与细胞动力学实验有关，在这些实验中，频繁地以尽可能少的样本浪费来采样生物系统是很重要的。为了解决这些需求，我们提出了一种双柱在线固相萃取（SPE）方法，能够浓缩和制备恒流样品，最小化甚至不损失样品。该策略特别针对微流控生物反应器研究进行了评估，旨在确定合适的样品流速、时间分辨率和分析物浓度。在这项工作中，我们证明了这种策略可以用于低至 500nL/min 的流速，时间分辨率约为 3 分钟，对于代谢物，分析物的加载量从飞摩尔到皮摩尔不等。在这些条件下，即使在飞摩尔负载下，回收率也约为 80%。
