Van Kien Nguyen, Jeong Young Han, Seog David Jin Han, Ryoo Jae Jeong
Department of Chemistry Education, Kyungpook National University, Daegu, 702-701, the Republic of Korea South Korea.
Department of Chemistry Education, Kyungpook National University, Daegu, 702-701, the Republic of Korea South Korea.
J Chromatogr A. 2023 Nov 8;1710:464402. doi: 10.1016/j.chroma.2023.464402. Epub 2023 Sep 20.
Based on the previous ultrasound-assisted chromatography (UAC) studies on plastic and stainless steel (SS) columns, this study explores the UAC mechanism by comparatively analyzing ultrasound effects on plastic and SS columns with C18 stationary phase when separating a mixture of polycyclic aromatic hydrocarbons (PAHs) under various ultrasound intensities. The results showed a substantial difference in H values between the PEEK and SS columns under the influence of ultrasound agitation. Specifically, for the pyrene peak, as the ultrasonic intensity increased from 0% to 100% of 900 W, the H values of the SS column slightly rose from 8.82 μm to 9.86 μm. Conversely, the corresponding values for the PEEK column exhibited a significant 12-fold increase from 11.5 μm to 134 μm. The findings demonstrated poor penetration of ultrasound energy through the SS column, and the temperature rise of the medium induced by the ultrasound was the primary contributing factor to PAH separation. However, ultrasound easily penetrated through the plastic column, resulting in acoustic cavitation within the C18 polyether ether ketone (PEEK) column. Cavitation induced heat generation and contributed to a decrease in retention time and the magnitude of peak broadening or distortion, depending on the specific ultrasonic energy. Based on the estimated change in inlet temperature of the PEEK column due to an acoustic effect, the comparison with temperature effects under non-sonic conditions consistently demonstrated a stronger acoustic effect in reducing the retention time, by 2-9%, depending on specific peaks and pairs. We revisited the previously described separation mechanism of ultrasound-assisted ion chromatography and conjoined with our findings to infer and establish a thorough explanation for the previously unexplained separation mechanism of chiral separation and size exclusion chromatography by UAC using SS columns.
基于之前对塑料柱和不锈钢（SS）柱的超声辅助色谱法（UAC）研究，本研究通过比较分析在不同超声强度下分离多环芳烃（PAHs）混合物时，超声对具有C18固定相的塑料柱和SS柱的影响，来探索UAC的机制。结果表明，在超声搅拌的影响下，聚醚醚酮（PEEK）柱和SS柱的H值存在显著差异。具体而言，对于芘峰，随着超声强度从900 W的0%增加到100%，SS柱的H值从8.82μm略有上升至9.86μm。相反，PEEK柱的相应值则从11.5μm显著增加了12倍，达到134μm。研究结果表明超声能量透过SS柱的穿透性较差，超声引起的介质温度升高是PAH分离的主要促成因素。然而，超声很容易穿透塑料柱，导致在C18聚醚醚酮（PEEK）柱内产生声空化。空化引起热量产生，并导致保留时间减少以及峰展宽或变形的程度变化，这取决于特定的超声能量。基于PEEK柱入口温度因声学效应而产生的估计变化，与非超声条件下的温度效应进行比较，始终表明声学效应在减少保留时间方面更强，减少幅度为2 - 9%，具体取决于特定的峰和峰对。我们重新审视了之前描述的超声辅助离子色谱的分离机制，并结合我们的研究结果进行推断，为之前使用SS柱的UAC对手性分离和尺寸排阻色谱的未解释分离机制建立了全面的解释。
