FlashPack enables packing of 50cm columns with 2mircon particles in less than an one hour

Usually column packing using sub micron particle requires packing pressures of sometimes more than 1000bars. Such workflows require special high pressure equipment and take more or less time since packing time for a given column length depends on the concentration of the particle suspension.

FlashPack provides a new column packing methodology for highly concentrated sub-2µm sorbent suspension (up to 1000mg/mL) at relatively low pressure of 100bar by overcoming particle aggregation. Thus, column packing procedures utilizing the FlashPack setup are a 100-times faster for a given column length than conventional column packing approaches.

This is achieved by  the unique setup consisting of a "pressure bomb"  which provides a pressure gradient and therefore creates a continuous stream of particles from the high pressure region (suspension) into the empty capillary placed within the low pressure region. Secondly, the capillary is mechanically strapped close to the bottom of the beaker to stay in position even at higher pressures and flow rates. Thirdly, application of an magnetic stirrer which provides a turbulent flow to homogenize the suspension and more importantly which continuously taps the proximal end of the capillary column to avoid particle aggregation at the entrance of the capillary while loading.

Overcoming the issues of particle aggregation enables packing of a 50cm column with 2µm particles in less than an hour.

Source: https://www.biorxiv.org/content/early/2018/09/26/426676.full.pdf+html

Ionic liquid matrices in MALDI MS

I know that sometimes glyercol is used a liquid matrix in IR MALDI, but I have ever heard about Ionic Liquid Matrices (ILMs) before. These type of matrices are trying to eliminate the drawbacks of commonly used MALDI matrices, which in most of the cases are organic acids, having a really pKa in order to achieved analyte protonation.

ILMs have a low melting point, low vapor pressure and high stability at AP and vacuum. They do not create dangerous fumes and are considered to be a greener technology compared to conventional MALDI Matrices. They do not display crystallization, therefore sample preparation is supposed to be really homogeneous - which is one of the biggest advantages applicational-wise. So there is no need to find the “sweet” spots on your sample anymore.

ILMs are composed of a mixture of organic salts and bases. This unique mixture leads to a high ionization performance with the analyte due to ion pairing via electrostatic or hydrogen bonding between the matrix compounds and impurities. Since the protons are originated from the salt rather than from a weak carboxylic acid group ILMs display higher proton exchange efficiencies compared to conventional matrices.

They do not cause fragmentation (even for non-covalent bonds) or cluster and alkali adduct formation. Thus, they are less prone to denaturation of biomolecules compared to acidic DHB and CHCA (pKa of 3 and 1.2) matrixes. ILM can be pH controlled by the organic base to minimize degradation, denaturation or fragmentation of labile biomolecules at low pHs.

Additionally, strength and concentration of base regulates the UV-absorbance, since a difference in charge status changes the localization of electrons within the molecule therefore changes the absorbance properties of the matrix towards lower (hypsochromic shift) or higher (bathochromic shift) wavelengths.


Source:
https://www.omicsonline.org/open-access/ionic-liquids-matrices-for-laser-assisted-desorptionionization-massspectrometry-2469-9861-1000109.php?aid=65371