Articles by Danijela Kocic in JoVE
Other articles by Danijela Kocic on PubMed
Using Active Flow Technology Columns for High Through-put and Efficient Analyses: The Drive Towards Ultra-high Through-put High-performance Liquid Chromatography with Mass Spectral Detection Journal of Chromatography. A. Nov, 2015 | Pubmed ID: 26363945 The performance of active flow technology chromatography columns in parallel segmented flow mode packed with 5μm Hypersil GOLD particles was compared to conventional UHPLC columns packed with 1.9μm Hypersil GOLD particles. While the conventional UHPLC columns produced more theoretical plates at the optimum flow rate, when separations were performed at maximum through-put the larger particle size AFT column out-performed the UHPLC column. When both the AFT column and the UHPLC column were operated such that they yielded the same number of theoretical plates per separation, the separation on the AFT column was twice as fast as that on the UHPLC column, with the same level of sensitivity and at just 70% of the back pressure. Furthermore, as the flow velocity further increased the performance gain on the AFT column compared to the UHPLC column improved. An additional advantage of the AFT column was that the flow stream at the exit of the column was split in the radial cross section of the peak profile. This enables the AFT column to be coupled to a flow limiting detector, such as a mass spectrometer. When operated under high through-put conditions separations as fast as six seconds, using mobile phase flow rates in the order of 5-6mL/min have been recorded.
A New Approach to Live Reaction Monitoring Using Active Flow Technology in Ultra-high-speed HPLC with Mass Spectral Detection Journal of Mass Spectrometry : JMS. Dec, 2015 | Pubmed ID: 26634974 A new type of chromatography column referred to as a parallel segmented flow (PSF) column enables ultra-high-speed high-performance liquid chromatography-MS to be undertaken. This occurs because the separation efficiency obtained on PSF columns has been shown in prior studies to be superior to conventional columns, and the flow stream is split radially inside the outlet end fitting of the column, rather than in an axial post-column flow stream split. As a result, the flow through the column can be five times higher than the flow through the MS. In this work, the degradation of amino acids in dilute nitric acid was used to illustrate the process. Separations were obtained in less than 12 s, although the reinjection process was initiated 6 s after the previous injection. The degradation rate constant of tryptophan, in the presence of tyrosine and phenylalanine, was determined. Copyright © 2015 John Wiley & Sons, Ltd.