Grau José, Moreno-Guzmán María, Arruza Luis, López Miguel Ángel, Escarpa Alberto, Chisvert Alberto
GICAPC Research Group, Department of Analytical Chemistry, University of Valencia, 46100 Burjassot, Valencia, Spain.
Department of Chemistry in Pharmaceutical Sciences, Analytical Chemistry, Faculty of Pharmacy, Complutense University of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
Analyst. 2023 Feb 27;148(5):1050-1057. doi: 10.1039/d2an02085h.
Miniaturized magnetic-based pipette tip microextraction is presented as a sample preparation approach for microsamples. It involves quick dispersion of a diminutive amount of a magnetic sorbent material in a low-volume sample (10 μL) to entrap the target analytes. Next, the dispersion is aspirated using a (semi)automatic pipette through a pipette tip with a small cubic neodymium magnet inside, which retrieves the magnetic sorbent containing the analytes. After discarding the rest of the sample, the sorbent is properly rinsed by aspirating/dispensing deionized water, and then, the analytes are eluted by aspirating/dispensing an appropriate solvent. This approach was employed for the determination of free cortisol in serum and urine from very low birth weight preterm newborns, a vulnerable patient group who present low availability for sampling biological fluids. A magnetic immunosorbent made of a cortisol antibody was employed for the selective extraction, followed by liquid chromatography-tandem mass spectrometry. Good analytical features were obtained, such as limits of detection and quantification of 0.08 and 0.27 ng mL, respectively, linearity up to 50 ng mL ( > 0.999), RSD values under 15% and relative recoveries between 91 and 111%. The cross-reactivity with other glucocorticoids (, cortisone and prednisolone) was evaluated to show the selectivity of the extraction. Finally, the method applicability was demonstrated towards the determination of free cortisol in the serum and urine samples from low birth weight preterm newborns.
微型磁基移液器吸头微萃取技术作为一种用于微量样品的样品前处理方法被提出。该方法包括将少量磁性吸附剂材料快速分散在小体积样品（10μL）中，以捕获目标分析物。接下来，使用（半）自动移液器通过内部装有小立方钕磁铁的移液器吸头吸取分散液，从而回收含有分析物的磁性吸附剂。弃去剩余样品后，通过吸取/ dispense去离子水对吸附剂进行适当冲洗，然后通过吸取/ dispense适当溶剂洗脱分析物。该方法用于测定极低出生体重早产儿血清和尿液中的游离皮质醇，这是一类难以获取生物体液样本的脆弱患者群体。采用由皮质醇抗体制成的磁性免疫吸附剂进行选择性萃取，随后进行液相色谱 - 串联质谱分析。获得了良好的分析特性，如检测限和定量限分别为0.08和0.27 ng/mL，线性范围高达50 ng/mL（>0.999），相对标准偏差值低于15%，相对回收率在91%至111%之间。评估了与其他糖皮质激素（如可的松和泼尼松龙）的交叉反应性，以显示萃取的选择性。最后，证明了该方法在测定低出生体重早产儿血清和尿液样品中游离皮质醇方面的适用性。 （注：原文中“dispensing”未翻译完整，推测可能是“dispensing and aspirating”之类的表述，这里按原文翻译）
