Department of Environmental Science and Bioscience, Faculty of Natural Science, Kristianstad University, SE-291 39 Kristianstad, Sweden.
Molecules. 2019 Apr 11;24(7):1426. doi: 10.3390/molecules24071426.
By using an innovative, positive pressure sample loading technique in combination with an in-line filter of finely ground sand the bottleneck of solid phase extraction (SPE) can be reduced. Recently published work by us has shown the proof of concept of the technique. In this work, emphasis is put on the SPE flow rate and method validation for 26 compounds of emerging environmental concern, mainly from the 1st and 2nd EU Watch List, with various physicochemical properties. The mean absolute recoveries in % and relative standard deviations (RSD) in % for the investigated compounds from spiked pure water samples at the three investigated flow rates of 10, 20, and 40 mL/min were 63.2% (3.2%), 66.9% (3.3%), and 69.0% (4.0%), respectively. All three flow rates produced highly repeatable results, and this allowed a flow rate increase of up to 40 mL/min for a 200 mg, 6 mL, reversed phase SPE cartridge without compromising the recoveries. This figure is more than four times the maximum flow rate recommended by manufacturers. It was indicated that some compounds, especially pronounced for the investigated macrolide molecules, might suffer when long contact times with the sample glass bottle occurs. A reduced contact time somewhat decreases this complication. A very good repeatability also held true for experiments on both spiked matrix-rich pond water (high and low concentrations) and recipient waters (river and wastewater) applying 40 mL/min. This work has shown that, for a large number of compounds of widely differing physicochemical properties, there is a generous flow rate window from 10 to 40 mL/min where sample loading can be conducted. A sample volume of 0.5 L, which at the recommended maximum flow rate speed of 10 mL/min, would previously take 50 min, can now be processed in 12 min using a flow rate of 40 mL/min. This saves 38 min per processed sample. This low-cost technology allows the sample to be transferred to the SPE-column, closer to the sample location and by the person taking the sample. This further means that only the sample cartridge would need to be sent to the laboratory, instead of the whole water sample, like today's procedure.
通过使用创新的正压样品加载技术并结合精细研磨砂的在线过滤器，可以减少固相萃取（SPE）的瓶颈。我们最近发表的工作已经证明了该技术的概念验证。在这项工作中，重点是 26 种新兴环境关注化合物的 SPE 流速和方法验证，这些化合物主要来自欧盟第 1 和第 2 个关注清单，具有各种物理化学性质。在三个研究的流速 10、20 和 40 mL/min 下，从加标纯水样品中测定的 26 种化合物的平均绝对回收率（%）和相对标准偏差（RSD）（%）分别为 63.2%（3.2%）、66.9%（3.3%）和 69.0%（4.0%）。所有三种流速均产生了高度可重复的结果，这允许在不影响回收率的情况下，将 200 mg、6 mL 反相 SPE 小柱的流速提高到 40 mL/min。这一数字是制造商推荐的最大流速的四倍多。结果表明，某些化合物，特别是所研究的大环内酯类化合物，当与样品玻璃瓶长时间接触时可能会受到影响。减少接触时间会在一定程度上减少这种复杂性。在应用 40 mL/min 对加标富营养池塘水（高浓度和低浓度）和接收水（河流和废水）进行实验时，也表现出非常好的重复性。这项工作表明，对于具有广泛不同物理化学性质的大量化合物，在 10 至 40 mL/min 的范围内有一个很大的流速窗口，可以进行样品加载。0.5 L 的样品体积，在推荐的最大流速 10 mL/min 下，之前需要 50 分钟，现在可以使用 40 mL/min 的流速在 12 分钟内处理。这为每个处理的样品节省了 38 分钟。这种低成本技术允许将样品转移到 SPE 柱上，更接近样品位置，并由取样人员进行操作。这意味着，与当前的程序相比，只需将样品小柱寄往实验室，而不是像现在这样将整个水样寄往实验室。
