PROVIDES ADDED FUNCTIONALITY FOR HIGH-RESOLUTION ULTRASONIC SPECTROSCOPY High Resolution Ultrasonic Spectroscopy is a novel technique for non-destructive material analysis based on precision measurements of parameters (velocity and attenuation) of high-frequency sound waves, propagating through analysed samples. These waves propagate through most materials including opaque samples and allow direct probing of intermolecular forces. The award winning range of HR-US ultrasonic spectrometers from Ultrasonic Scientific provide an unprecedented set of new analytical capabilities for research, product development, quality and process control in biotech, pharmaceutical, food, chemical and petrochemical, polymer and other industries. Applications include analysis of chemical reactions, conformational transitions in polymers and biopolymers, aggregation and gelation phenomena, particle sizing, phase transitions, stability of emulsions and suspensions, formation of micelles and CMC measurements, ligand binding, composition analysis and many others. Titration is a routine analytical method in the modern laboratory, which allows analysis of molecular binding as well as a quantitative determination of a specific substance (analyte) in a sample by stepwise adding a second component (titrant) which reacts with the substance of interest. The HR-US Titration System (left on Figure 1) provides users of the HR-US Series Ultrasonic Spectrometer with the capability to perform titrations with accuracy and confidence. The system includes the titration module, specially designed stirring systems for fast homogenous mixing and operating software. It is of particular use for those involved in binding studies, protein studies, critical micelle concentration analysis, molecular association, kinetics of chemical reactions and other measurements. |
Analysis of molecular binding without markers HR-US spectrometers work as universal detectors of molecular transformations because they probe directly the intermolecular forces. Any change in molecular structure, including molecular binding, formation of molecular aggregates, etc affects the intermolecular interactions in the sample and therefore can be detected with ultrasonic measurements. The measured ultrasonic titration profile, dependence of ultrasonic velocity and attenuation on the concentration of titrant, can be recalculated into the binding isotherm (dependence of concentration of bound titrant on the concentration of titrant in solution), which provides binding constants (affinities) and binding stoichometries. Binding constants give the free energy of binding and their temperature dependence allows calculation of entropy and enthalpy of binding. Because the measurements do not require any optical transparency or other properties of solution and solutes the complex sample preparation procedures, often required by other techniques, become obsolete. Another advantage of HR-US titration technique is the ability to analyse molecules in their original state without immobilising procedures, transferring into another environment etc. Figure 2 shows the principles of ultrasonic titration. The ultrasonic cell is filled with solution of analyte (polymer in the figure). Then titrant (ligand) is injected stepwise in the solution and then in the reference cell filled with a similar solution, but without analyte. Ultrasonic parameters of the solution are constantly monitored and the contribution of the titrant is subtracted using the reference cell data. The curve on the screen of the monitor represents a change in ultrasonic velocity caused by the binding of ligand with polymer. This curve than is recalculated into the binding isotherm, and binding constants and stoichometries or the equivalent point is obtained. Example applications: binding of ions with chelators (EDTA, etc), polymer-ligand binding, antigen-antibody binding, equivalence point determination. 
Wet Chemistry and Ultrasonic Spectroscopy Wet chemistry is a classical technique for measurements of concentrations of various components in analysed samples. This technique includes a series of chemical treatments of the sample (extractions, etc), which allow transferring the component of interest in the environment where its concentration can be measured. The concentration is often measured through a titration by another component (titrant), which react with the component of interest (analyte) and produces a visible changes in colour (optical spectrum), pH or other parameters of the solution, which can be analysed quantitatively. The equivalence point on the titration curve gives the concentration of the component of interest, which than is recalculated into the concentration in the original sample. The key element of this analysis is an appropriate detector, which can provide quantitative information on the amount of titrant bound or reacted with the analyte and which determines the complexity of the wet chemical routine. Because HR-US titrations allow analysis of any molecular transformations and because the measurements do not require any optical transparency or other properties of solution and solutes many steps in we chemical routines can be excluded. In addition one device, HR-US spectrometer, can be used for various analytes and titrants those, which cannot be used with another detectors. Application list includes determination of concentration of a broad range of components (metal ions, sugars, proteins, water, etc). Kinetics of Chemical Reactions The Titration Accessories allow direct monitoring of chemical reactions by measuring the change in concentration of the substrates and products with HR-US spectrometers. This technology is extremely sensitive, non-destructive, requires no markers and can be used in non-transparent samples, such as emulsions, dispersions etc (e.g. blood, milk). Figure 3 shows the principles of ultrasonic analysis of kinetics of depolymerisation of polysaccharide. The reaction is started by injection of enzyme with the Titration Accessories. Specially designed stirring system (part of the Accessories), provides fast and uniform mixing of the injected enzyme. Ultrasonic parameters (velocity and attenuation) are constantly monitored and recalculated into the concentration of product and the effective molecular weight of the polymer. Example applications: determination of activity of enzymes, kinetics of organic reactions, etc. 
Double stirring system, sedimentation, creaming, etc. Titration accessories include specially designed double stirring system, which allows fast and homogenous mixing of the sample. It consist of the top and the bottom stirrers with adjustable speed. The software allows to program the ON and OFF state if the stirrers as well as perform the measurement under continuous stirring. The last option allows analysis of sedimenting or creaming samples (emulsions, suspensions, gas bubbled samples, etc) by providing their homogenous consistency through an effective stirring. Effective stirring allows performance of temperature ramps, titrations and other measurements in sedimenting samples. Kinetics of sedimentation and creaming processes can simply be analysed by monitoring of the change of ultrasonic parameters after the programmed stop of stirring. Example applications: gelation in sedimenting samples (starches, etc), stability of emulsions and suspensions, kinetics of creaming/sedimentation, etc. Specifications Titration syringe sizes | 5 µL to 500 µL |
Syringe Speed | From 0.5 seconds to 60 minutes per stroke |
Resolution | 2000 steps standard/full resolution | Accuracy | +/- 1 % (reproducibility within 0.2%) | Stirring speeds | 100 to 1400 RPM | Operating Voltage | 110 to 240 VAC, 50/60 Hz |
Size | W 26 cms X H 14 cms X D 30 cms |
Ordering Information “T” Option | for HR-US 102 Series Spectrometers | HR-EX-TS | External Titration Accessory, including software, 25 µL syringe (or other on request) and accessories. |
This technology is protected by granted patents and pending patent applications |
