Technical notes and applications

Notes of interest from Malvern Panalytical, Micromeritics, Fluid Imaging, Biolin, Freeman, Netzsch, HORC, SMS, APL, PID, and our own technical team.

When measuring  the Nitrogen BET SSA of of low surface  Helium free space measurements become very important.

In BET measurements we want to know how much Nitrogen gas adsorbs onto the sample surface. As we can only measure what is dosed we need to know how much is left in the sample tubes as in (Q adsorbed = Q dosed – Q residual). Sometimes the tube volume above the sample holds more gas than adsorbs – so the error are significant. Even using Krypton as a analyte probe doesnt change the need to measure FS.

Running a measurement with a non-condensing gas like He before or after the BET run allows us to analyse that volume, and further separate it into Warm FS and Cold FS and properly accounting for the missing “residual”.

For some years scientists have been worried about the world’s declining stocks of Helium. And industrial gas suppliers have started restricting or rationing Helium deliveries to essential purposes only.

While He usage for Nitrogen BET experiments is low in absolute volume terms, there are no ways around the need to make the measurement. Calculating FS is possible but it is fiddly and not as precise. 

Driven by this need researchers have worked on He exploration. Recent discoveries show Scientists unearth one of world’s largest helium gas deposits | News | Chemistry World and Vast new reserves of helium discovered (cosmosmagazine.com).  So now we can return with confidence to using Helium for essential purposes like scientific analysis of Surface Area and True Density.

The RIO100 is a unique dual purpose Raman immersion and solids probe.

The HORC Raman RIO 100 is an immersion optic that can collect Raman spectra from turbid liquids. This probe has an adjustable retroreflector and can be added to any Kaiser RXN1 or RXB2 or other quality Raman system.

But remove the reflector and you have complete RIO100 Non-Contact optic that can collect spectra direct from solid surfaces without the usual surface noise.

The overpot below shows Raman spectra captured through the surface of a coated Excedrin tablet, alongside a comparable and conventional Raman spectra from a Research Microscope where the surface was shaved to bare the content.

Non-local density functional theory (NLDFT) 

Micromeritics  has begun the release of a new series of NLDFT models for the characterization of porous carbons. These new models are based upon the leading work of Jacek Jagiello and James Olivier and employ NLDFT techniques for 2-D finite geometry of pores to calculate the pore size distribution of materials from adsorption isotherms. This new technique was first published in the Journal of Physical Chemistry for nitrogen on carbon.

Non-local density functional theory (NLDFT) models are used to determine the porosity of a sample – pore size and pore size distribution – from measured gas adsorption isotherms. Micromeritics provide simple, easy to understand answers to frequently asked questions relating to this topic, supplying the background understanding needed for effective application of this powerful mathematical tool. 

The latest v 3 of the SAIEUS program described on www.nldft.com Non-local density functional theory (NLDFT) modelscan be downloaded from the Micromeritics web site.

Using Polarizers in DLS measurements.

The latest Zetasizer Advanced Pro and Ultra models have an inbuilt filter wheel with a fluorescence filter, a vertical polarizing filter and a horizontal polarizing filter factory installed. The polarising filters bring new capabilities to your DLS measurements and some surprising benefits.

The Vertical polarizer filter can bring you the sort of quality DLS performance you get with glass cuvettes while using low-cost plastic cuvettes – by reducing the scattering noise. For more information on this effect contact Particular Sciences or follow www.Materials-talks.com. As an example of the effectiveness of this use of polarizers in DLS measurements, look at the graph to the side.

The Vertical Polarizer can also be used during NIBS measurements of concentrated samples to reduce multiple scattering making the measurements at higher concentrations more realistic. This approach was reported by Ragy Ragheb & Ulf Nobbman in Nature’s scientific reports 10, article 217168, 10 Dec 2020

Last but not least, by applying Horizontal Polarization you differentiate Rotational Diffusion from the classic Translational Diffusion we normally use to calculate particle size. This can help identify particles having a shape that is creating some slower than expected diffusion. For more information on this effect contact Particular Sciences or follow www.Materials-talks.com .

Malvern Panalyical role in advancing SARS-COV-2 vaccine research.

With 7 different Covid-19 vaccines publicly available and > 1 billion doses administered, Malvern Panalytical shows how they have supported these developments. Their analytical instruments and expertise supported SARS-CoV-2 vaccine labs across the globe, advancing the development of all 3 major vaccine types currently on the market.

For more information on the technologies and application spaces involved go to the  “Malvern Panalyticals-talks” blog, click here.

Flow Imaging Microscopy with Light Obscuration

Yokogawa Fluid Imaging Technologies, Inc. manufactures particle analysis instrumentation with digital imaging technology. While the FlowCam series capture the best images possible, their new FlowCam + LO brings extra capabilities to particle detection.

Sub-visible particle detection by flow imaging technologies is classically used in bio-pharma to to view particles and understand more about the nature of any contamination or aggregates.  These labs usually QC their samples on particle counters according to the USP <788> standard. FlowCam + LO tasks flow imaging and light obscuration in one compact and easy to use system.

To learn more about how flow imaging with FlowCam works follow this link.

To download the FlowCam + LO brochure follow this link.

To read the Fluid Imaging informative e-Book please visit the Yokogawa Fluid Imaging Technologies web site and register for your own copy. 

Otherwise please contact Particular Sciences and arrange sample testing or a demonstration.

Images taken on a FIT FlowCam