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  • Light Scattering Goniometer Reveals Why Molybdenum Solutions Are Blue...Read More

  • Aggregation Detection by Dynamic Light Scattering...Read More

  • Characterising Liposomes & Liposome-Drug Conjugates...Read More

  • Accurate Determination of Structure & Branching in Complex Polymers...Read More

  • Optimised Zeta Potential Measurement in Organic & Aqueous Media...Read More

  • Differential Refractometer for Precise dn/dc Determination...Read More

  • Automatic Determination of Zeta Potential Isoelectric Point...Read More

  • Characterization of Polymeric Microgels & Nanogels...Read More

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    Light Scattering Goniometer Reveals Why Molybdenum Solutions Are Blue

    Testa Analytical Solutions e.K reports on how a BI-200SM light scattering goniometer system with autocorrelator has helped researchers at a prestigious government laboratory to solve the enigma of why aqueous molybdenum solutions are blue.

    A spokesperson from the Department of Physics at the government laboratory said "Molybdenum and oxygen can combine to form a wide variety of structures, and some polyoxomolybdate (POM) molecules are the biggest inorganic molecules known, achieving similar sizes to proteins". He added "The electronic state of the POMs is responsible for imparting a blue color to the surrounding solution, as the giant POMs cluster together rather than existing as single ions. Because of the size of the POMs, we realized we could use our BI-200SM light scattering goniometer to find out the actual structure of the complexes and we subsequently discovered a unique blackberry arrangement that we believe represents a new, stable solute state. It has changed our understanding of the solution behavior of inorganic molecules when they reach nanometer sizes."

    The Bl-200SM goniometer system is a precision research grade instrument designed for exacting light scattering measurements. Based on a special turntable with precision ball bearings and stepping motor, the Bl-200SM's modular, automated design and quality construction guarantee precise measurements due to the wobble-free movement of the detector. As you would expect from a research grade system the BI-200SM can measure light scattering over a wide angular range (8° to 155° with 25 mm cells) and offers fine adjustment of measurement angles to 0.01° directly using a large, fine-control knob. Fine-screw vertical adjustment makes centre of rotation measurement easier when aligning cells. Precise repeatable data is ensured by automated heating and cooling of the sample cell using and standard external recirculating system. Field proven in hundreds of labs around the world the BI-200SM light scattering goniometer system is ideal for even the most demanding macromolecular studies and submicron particle sizing applications.

    For further information on the BI-200SM research goniometer system please visit www.testa-analytical.com/index.html?dc=Scattering&sn=1 or contact Testa Analytical Solutions on +49-30-864-24076 / info@testa-analytical.com.

     

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    Aggregation Detection by Dynamic Light Scattering

    Testa Analytical Solutions e.K reports on how its NanoBrook Omni particle size analyser and BI-ZTU autotitrator can be used together to detect the onset of aggregation in nanoparticles.

    The NanoBrook Omni instrument offers a single powerful and accurate solution for particle sizing and zeta potential analysis. The instrument allows users to measure samples in nearly every possible suspension environment from high salts such as PBS and sea water to organic solvents and aqueous solutions. The instrument offers unmatched particle sizing, with the highest sensitivity, utilizing three light scattering measurement angles for truly unbiased measurement results. The BI-ZTU autotitrator option for the NanoBrook Omni provides an ideal solution for automated measurement of particle size as a function of pH.

    Applications that use iron oxide nanoparticles are vast and growing due to its stability, low toxicity, and magnetic properties. Given the great potential for applications using iron oxide, it is highly desirable to understand the effect of chemical changes to the surface of the nanoparticle.

    Aggregation of nanoparticles can occur due to changes in pH or temperature. In a new applications report* researchers show how Dynamic light Scattering (DLS) offers a quick and easy way of determining the effective diameter (or size) of iron oxide nanoparticles and an autotitrator can help automate the process of detecting changes in particle size as a function of pH. They conclude that the NanoBrook Omni particle size analyser and BI-ZTU autotitrator provide a highly effective instrumental solution for the detection on aggregation of nanoparticles due to changes in pH.

    For a copy of the application report please go to www.testa-analytical.com/index.html?dc=Knowledge&sn=14. For further information on the NanoBrook Omni instrument please visit www.testa-analytical.com/index.html?dc=Zeta&sn=1 or contact Testa Analytical Solutions on +49-30-864-24076 / info@testa-analytical.com.

     

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    Characterising Liposomes & Liposome-Drug Conjugates

    Testa Analytical Solutions e.K reports on a growing number of customers using their Nanobrook ZetaPALS instrument to accurately determine the size and surface charge of liposomes, exosomes and microvesicles.

    Liposomes or Lipid-drug conjugates used as targeted drug delivery systems are hot topics in the field of pharmaceutical research. The size and charge at the surface of the particle plays a deciding role for proper gastrointestinal uptake of the synthesized Liposome Drug Conjugates (LDC) nanoparticles and their systemic clearance by the reticuloendothelial system. It is therefore always important to determine the size of LDC nanoparticles accurately.

    A new application note is available describing how the Nanobrook ZetaPALS instrument, using a phase analysis light scattering technique, has been used to accurately determine the size and surface charge of liposomes, exosomes and microvesicles.

    The NanoBrook ZetaPALS is a highly accurate and easy-to-use Zeta Potential Analyzer using Phase Analysis Light Scattering (PALS).  This revolutionary instrument has been designed to eliminate the short comings inherent in other zeta potential instruments. Using the PALS configuration, the Nanobrook ZetaPALS can be used to measure mobilities up to 3 orders of magnitude lower than with a conventional laser Doppler electrophoresis system. The NanoBrook ZetaPALS measures complete electrophoretic mobility distributions in just seconds.

    For a copy of the application note please visit www.testa-analytical.com/index.html?dc=Knowledge&sn=13. For further information on the NanoBrook ZetaPALS instrument please visit www.testa-analytical.com/index.html?dc=Zeta&sn=4 or contact Testa Analytical Solutions on +49-30-864-24076 / info@testa-analytical.com.

     

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    Accurate Determination of Structure & Branching in Complex Polymers

    The AYE Combo Refractometer / Viscometer from Testa Analytical Solutions e.K. sets a new standard for the detection of intrinsic viscosity of highly diluted samples.

    This unique instrument is designed to have a high performance refractometer as an integral part of the viscometer, therefore both concentration and viscosity are measured at exactly the same time on the very same sample segment.

    As a consequence the AYE Combo Refractometer / Viscometer allows a much more accurate determination of molecular parameters and is particular suitable for applications focused on determining the structure and branching of complex polymers.

    Using a viscometer within a GPC/SEC System, requires a source of a concentration signal to complete the necessary calculations. The limitation of using a standard Differential Refractive Index (DRI) detector for this task, is that it must deliver a corresponding concentration signal for each point on the viscosity curve. This is possible with two separate instruments, precision of the results however, will be limited due to the volume difference of the detectors. A combination instrument, such as the AYE Combo, where both detectors are integral part of each other, overcomes these limitations and allows a much better determination of the sample under investigation.

    For further information on the AYE Combo Refractometer / Viscometer please visit www.testa-analytical.com/index.html?dc=AYE&sn=2 or contact Testa Analytical Solutions on +49-30-864-24076 / info@testa-analytical.com.

     

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    Optimised Zeta Potential Measurement in Organic & Aqueous Media

    Testa Analytical Solutions e.K reports that its Nanobrook ZetaPALS zeta potential analyser is uniquely optimised to make sensitive and precise measurements in both organic and aqueous media.

    Typically making zeta potential measurements in organic (non polar) solvents requires much higher sensitivity than in aqueous (polar) solutions. The Nanobrook ZetaPALS analyser achieves this using phase analysis light scattering (PALS). Using proprietary PALS technology, the Nanobrook ZetaPALS can be used to make zeta potential measurements up to 1,000 times more sensitive than traditional light scattering methods based on the shifted frequency spectrum.

    Made of PEEK with  a Palladium (Pd) electrode assembly - the Nanobrook ZetaPALS measurement cell is resistant to the widest range possible of solvents, and offers excellent chemical stability, easy cleaning and long-term top performance. Precision Peltier temperature control enables precise zeta potential measurements from -5 °C to 110 °C. For laboratories tasked with just analysing aqueous solutions inexpensive disposable plastic cells can be used with the high performance electrode assembly. For applications in organic solvents, quartz cells are available.

    Almost all particulate or macroscopic materials in contact with a liquid acquire an electronic charge on their surfaces. Zeta potential is an important and useful indicator of this charge which can be used to predict and control the stability of colloidal suspensions or emulsions, for example. The greater the zeta potential the more likely the suspension is to be stable because the charged particles repel one another and thus overcome the natural tendency to aggregate. The measurement of zeta potential is often the key to understanding dispersion and aggregation processes in applications as diverse as water purification, ceramic slip casting and the formulation of paints, inks and cosmetics.

    For further information on using a Nanobrook ZetaPALS analyser to zeta potential measurement in both organic and aqueous media please visit www.testa-analytical.com/?dc=Zeta" or contact Testa Analytical Solutions on +49-30-864-24076 / info@testa-analytical.com.

     

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    Differential Refractometer for Precise dn/dc Determination

    Testa Analytical Solutions e.K. has added the AYE Differential Refractometer to its existing line of high-performance instruments for chromatographic measurements.

    The AYE is a flexible differential refractometer that may be used in either static or dynamic mode. In static mode, the specific refractive index increment (dn/dc) of dissolved samples can be easily and precisely determined in just a few minutes. The specific refractive index increment is a critical parameter required to determine absolute molecular weight using static light scattering (SLS) detectors. This is because a relatively small error in dn/dc determination will lead to twice the error in calculating molecular weights. It is important also to determine the dn/dc value at the same wavelength as the SLS detector laser or a further error will be introduced, as dn/dc is strongly dependent from wavelength.

    The AYE differential refractometer offers a large number of wavelength options to enable precise matching of your SLS detector laser operating wavelength, thereby ensuring reliable and reproducible results every time.

    Where the dn/dc value of the sample is already known, the AYE differential refractometer can be used for precise and sensitive concentration determination. The amount of sample used for this can also be easily recollected and therefore utilized for further investigations.

    For further information on the AYE differential refractometer please visit www.testa-analytical.com/index.html?dc=dndc&sn=1 or contact Testa Analytical Solutions on +49-30-864-24076 / info@testa-analytical.com.

     

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    Automatic Determination of Zeta Potential Isoelectric Point

    Testa Analytical Solutions e.K reports on how automation of isoelectric point measurement can be achieved using a BI-ZTU autotitrator in combination with a Nanobrook zeta potential analyzer.

    The stability of a dispersion is commonly determined by zeta potential. However, the surface chemistry of solid particles in a dispersion can be modified by altering parameters such as pH, surfactant concentration and salt concentrations. Hence, it is important to determine how pH affects the zeta potential of a dispersion. By studying the isoelectric point, scientists can determine how pH affects zeta potential and therefore can determine at which pH the zeta potential is zero.

    The BI-ZTU autotitrator option for NanoBrook zeta potential analyzers is ideal for automatic determination of the isoelectric point of colloids, for the detection of the onset of aggregation as a function of pH and for measure effect of salt concentration (ionic strength) on zeta potential. Incorporating four pumps the BI-ZTU autotitrator provides unparalleled flexibility for optimising reagent use. Using a BI-ZTU autotitrator enables automatic addition of acid or base to adjust the pH of your sample, recording of pH, and loading of sample into the electrode cell of a Nanobrook zeta potential analyzer.  Using this set-up allows you to determine zeta potential at a particular pH and then automatically repeat the measurement for the next pH in the series.

    By minimising manual labour requirements using the BI-ZTU in combination with the Nanobrook zeta potential analyzer the cost of isoelectric point determination is drastically reduced.

    For further information on automatic determination of zeta potential isoelectric point please visit www.testa-analytical.com/index.html?dc=Zeta&sn=4 or contact Testa Analytical Solutions on +49-30-864-24076 / info@testa-analytical.com.

     

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    Characterization of Polymeric Microgels & Nanogels

    Testa Analytical Solutions reports how the Institute of Applied Radiation Chemistry at the Lodz University of Technology (Poland) determined molecular weight and radius of gyration of polymeric microgels and nanogels by static multiangle laser light scattering (SLS) measurements using a BI-200SM goniometer.

    A nanogel is a two-component system of a diameter in the range of tens of nanometers, consisting of an intramolecularly crosslinked polymer chain and solvent, typically water, filling the space between segments of the macromolecule. Microgels are bigger than nanogels and their size range is between 100 nm to 100 µm. A common method for synthesizing nanogels is linking the segments of a single macromolecule with the use of ionizing radiation, by intramolecular recombination of radiation-generated polymer radicals. The main advantage of this technique is absence of monomers, catalysts, surfactants or crosslinking agents. This method is an interesting alternative way of synthesizing polymeric carriers for biomedical applications.

    The aim of the study** by the Polish researchers was radiation synthesis and characterization of poly(acrylic acid) – PAA – nanogels and microgels.

    Dr Slawomir Kadlubowski from the Institute of Applied Radiation Chemistry commented "The BI-200SM goniometer is a precision instrument designed for demanding SLS measurements on macromolecules. As you would expect from a research grade system the BI-200SM can measure light scattering over a wide angular range at very high precision. We particularly liked the BI-200SM Particle Explorer software suite as it enabled us to make fast and easy data collection and analysis. These attributes combined with excellent technical support from Testa Analytical have enabled us to precisely characterise the complex PAA microgels and nanogels that we have synthesised".

    For further information on the BI-200SM research goniometer system please visit http://www.testa-analytical.com/index.html?dc=Scattering or contact Testa Analytical Solutions on +49-30-864-24076 / info@testa-analytical.com. For a full copy of The Institute of Applied Radiation Chemistry study please visit http://mitr.p.lodz.pl/biomat/?page_id=76 or contact Dr Slawomir Kadlubowski (slawekka@mitr.p.lodz.pl / +48-42-631-31-64).


    ** M. Matusiak, S. Kadlubowski, P. Ulanski; Radiation-induced synthesis of poly(acrylic acid) nanogels, Radiation Physics and Chemistry 142, 125 (2018) DOI:10.1016/j.radphyschem.2017.01.037

     

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