Studies on azaspiracid biotoxins. I. Ultrafast high‐resolution liquid chromatography/mass spectrometry separations using monolithic columns

Abstract

In this study, the performance of monolithic columns was evaluated for ultrafast liquid chromatography/mass spectrometry (LC/MS) analyses and for high-resolution separations of several azaspiracid biotoxin analogs. Because of their high permeability, monolithic columns offer a number of advantages over conventional packed columns; viz., very low backpressures and relatively flat van Deemter curves at high flow rates. That is, very high flow rates can be used for ultrafast analyses or, by using longer than normal columns, high-resolution separations are possible. In a series of experiments, we varied the mobile phase flow rates between 1 and 8 mL/min, and studied their impact on chromatographic parameters such as retention time, resolution, number of plates and pressure. The chromatographic run times could be reduced to ca. 30 s without a significant change in the separation efficiency. A signal intensity comparison revealed interesting differences between atmospheric-pressure chemical ionization (APCI) and electrospray ionization (ESI) in their flow-rate dependency. An explanation with respect to the behavior as of a mass-flow or a concentration-dependent device is given in the paper. Additionally, the column length was varied between 10 and 70 cm. As a result, the number of theoretical plates increased substantially. In the example shown in the report, an increase from 13 000 plates for a 10-cm column to 80 000 for a 70-cm column is demonstrated. In addition, the potential of the monolithic columns for high-resolution LC/MS separations is shown for a complex biotoxin mixture, which was separated on a 40-cm-long column.

Properties of Monolithic Silica Columns for HPLC

“…3,[49][50][51] An increase in the number of separated peaks per unit time can also be achieved by an increased separation speed made possible by monolithic silica columns. 52,53 This has also been shown for peptides and proteins (Fig. 8).…”

Mediterranean Azadinium dexteroporum (Dinophyceae) produces six novel azaspiracids and azaspiracid-35: a structural study by a multi-platform mass spectrometry approach

“…The MS behavior of AZAs is indeed characteristic and it has been studied widely using either tandem MS or high resolution MS analyzers [9,[23][24][25]. Over the last years, new dinophycean species other than A. spinosum have been identified as AZA producers, including Amphidoma languida from Bantry Bay and two species in the genus Azadinium, i.e., Azadinium poporum from the North Sea, Korea [12], and the China Sea [26], and Azadinium dexteroporum from the Mediterranean Sea [13].…”

Particle discriminator interface for nanoflow ESI-MS

“…Typical solution flow rates for LC-MS are on the order of 100 -2000 L/min. It has been common practice to split the LC flow, to reduce the volume of sample entering the electrospray source region [8], but recently new ion sources have been developed that allow stable operation with solution flow rates of greater than 2 mL/min [9]. The development of high flow rate electrospray ion sources has primarily been driven by the LC market because of the lack of LC systems available for routine operation at lower solution flow rates.…”