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Features at a glance
Brookhaven's NanoBrook Omni instrument combines the best technology from our particle/protein sizer and zeta potential analyzer in to one powerful and accurate solution for sizing and zeta potential analysis. Measure samples in nearly every possible suspension environment from high salts such as PBS and sea water to organic solvents and of course aqueous solutions. Particle and protein sizing, with the highest sensitivity, utilizing three measurement angles for truly unbiased measurement results. The NanoBrook Omni utilizes a backscattering angle as well as 90° and 15°.
Simple fluids like water (low viscosity), glycerin (high viscosity) are Newtonian and exhibit viscosity effects, the dissipation of energy when particles move in such fluids. But dissolve macromolecules in these liquids –synthetic or biopolymers—and networks can form. In addition to viscosity effects, there are now elasticity effects, the storage of energy when embedded particle move. By following the mean square displacement (MSD) of tracer (probe) particles in such fluid and microrheological properties such as η*, the complex viscosity, G″, the viscous loss modulus, and G′, the elastic storage modulus, can be determined as a function of frequency.
Measurement of the autocorrelation function (ACF) using DLS techniques yields the MSD of tracer particles, which, under the right conditions, can be used to determine η*, G″, and G′ over a range of frequencies much higher than mechanical rheometers can attain. Much smaller sample volumes, in the microliters, are possible compared to mechanical instruments. Finally, since strains result from the thermally driven motion of tracer particles, these much smaller strains allow the study of fragile samples. The study of viscoelasticity in aggregating dilute protein solutions is a prime example of the benefits of DLS microrheology.
Surface Zeta Potential - Principles of Operation
The Surface Zeta Potential feature allows the user to measure the electrical charge on materials like coated glass, plastic, tape, or other flexible surfaces. A series of measurements are taken on probe particles at different distances from a surface and the Surface Zeta Potential is calculated as shown:
The NanoBrook Omni is the one true “All-in-One” solution to particle and protein characterization.
Rapid, Reliable, and Accurate Analysis
The new NanoBrook Omni particle size and zeta potential analyzer incorporates all you need for fast, routine, sub-micron measurements of size and zeta potential. Based on the principles of Dynamic Light Scattering (DLS) for particle sizing and distribution, and based on doppler velocimetry (electrophoretic light scattering, ELS) for zeta potential measurement, most measurements only take a minute or two. The instrument also includes Phase Analysis Light Scattering (PALS) measurements for samples with low mobilities.
Three Scattering Angles:
Measurements of traditional colloids are usually made at 90° scattering angle due to the unbiased results measured. For nanoparticles and proteins, IgG and peptides, these < 50 nm samples can be measured using the backscattering angle (173°) for best S/N and reproducibility of measurements. Finally the 15° detection angle can be selected for added sensitivity with aggregation measurements. Zeta potential measurements are always performed using the 15° detection angle to minimize diffusion broadening.
Principles of Operation - Sizing
Dilute suspensions, on the order of 0.0001 to 1.0% v/v are prepared, using suitable wetting and/or dispersing agents, if required. A small ultrasonicator is sometimes useful in breaking up loosely-held agglomerates. At 173° sample volume may be reduced to 50 µL with a polystyrene, U-shaped, disposable cuvette and the sample is recoverable. At 90° square polystyrene or glass cells (two or three mL) are used, one as small as 10 µL (non-disposable). In addition, disposable, glass round cells with reusable Teflon stoppers are used for aggressive solvent suspensions. In all case, just a few minutes are required for the sample and cell to equilibrate with the actively controlled temperature environment inside the NanoBrook Omni.
Perhaps the most important benefit for users is the reproducibility from sample-to-sample, operator-to-operator, and instrument-to-instrument. The table below shows the results obtained for a polystyrene latex. Notice the Std. Error of the Effective (or Average) Diameter is less than 1% of the mean of the 10 repeated runs; the duration of each run was only five minutes. Such excellent repeatability is typical of the 90Plus for even routine QC analysis and ensures product quality time-after-time.
Instrument Nom. 90 Nom. 273 Nom. 111 Nom. 400 A 91±1 276±1 110±1 404±4 B 90±1 279±1 108±1 391±3 C 90±1 276±1 109±1 399±3 D 90±1 277±1 110±1 397±3 E - - 112±1 394±3 Ave. 90.3 277.0 109.8 397.0 Std. Err ±0.3% ±0.3% ±0.6% ±0.6% Test Results from Brookhaven Instruments Particle Size Analyzers(diameters, in nm)
The following table shows several aspects of the inter-instrument repeatability found with routine Brookhaven dynamic light scattering equipment. To test the reliability of the information obtained with Brookhaven Instruments a customer subjected five instruments in five locations with different operatorsand using four different samples to examination. The tabulation below shows excellent reproducibility with recognized standard materials and superb internal agreement. You can be confident of the results you get with your NanoBrook Omni!
The NanoBrook Omni particle size and zeta potential analyzer offers three choices. For routine determinations an average diameter (Eff. Dia.) and a measure of the distribution width (Polydispersity) are sufficient for many applications. This is illustrated above in Figure1 for the latex with a narrow size distribution. The second choice is to fit these values to a lognormal distribution, allowing the user to visualize the size distribution and to interpolate cumulative and differential results at 5% intervals.
Figure 2: Results from Test Bimodal Sample on NanoBrook Omni (diameters, in nm)
Figure 2 above shows an example of the third choice, suitable for more complicated, multimodal size distributions. Here, a numerical algorithm, including Mie theory, is used. These results are for a mixture of known latex particles. Positions of the measured particle sizes on the accompanying graph are in excellent agreement with the known sizes of 92 and 269 nm.
During a measurement, the display can be switched interactively between any one of these -- correlation function, lognormal, or multimodal -- each shown "live" as data are accumulated. The live display is particularly useful in determining the end-point of a measurement where multimodal distribution shape may be important
NanoBrook Omni - Phase Analysis Light Scattering
For measurements of very low mobilities, the Brookhaven NanoBrook Omni is the answer; the only answer! With concepts developed at Bristol University and Brookhaven Instruments, the NanoBrook Omni determines zeta potential using phase analysis light scattering: A technique that is up to 1,000 times more sensitive than traditional light scattering methods based on the shifted frequency spectrum.
Electrostatic repulsion of colloidal particles is often the key to understanding the stability of any dispersion. A simple, easy measurement of the electrophoretic mobility "even in nonpolar liquids" yields valuable information. Measurements made in water and other polar liquids are easy and fast with the NanoBrook Omni. Such measurements cover the range of typically ± (6 to 100) mV, corresponding to mobilities of ± 0.5-8x10-8 m2 /V·s. The NanoBrook Omni covers this full range, of course, and extends it by a factor of 1000 in sensitivity!
Principles of Operation - Zeta Potential
The NanoBrook Omni utilizes phase analysis light scattering to determine the electrophoretic mobility of charged, colloidal suspensions. Unlike its cousin, Laser Doppler Velocimetry (LDV, [sometimes called Laser Doppler Electrophoresis, LDE]), the PALS technique does not require the application of large fields which may result in thermal problems or denaturation. This is due to the fact that the measurement analyzes the phase shift. The particles need only to move a fraction of their own diameter to yield good results. In salt concentrations up to 2 molar and with electric fields as small as 1 or 2 V/cm enough movement is induced to get excellent results. In addition, the Autotracking feature compensates for thermal drift.
Simple and clear presentation
Figure 3 above shows the results of an actual experiment with a NanoBrook Omni instrument. The important parameters and results are seen at a glance. The excellent agreement of the five runs in this experiment is obvious as is the match of experimental curve (red, bold) and it's fitted version (red, thin). As with all Brookhaven instruments the user can simply produce a customized report.
The software can be easily customized to display the columns needed for a quick review of the important parameters as shown below.
Comprehensive Information - ELS
The NanoBrook Omni measures complete electrophoretic mobility distributions in seconds including multimodals. An example of bimodal zeta potential sample can be seen on the result screen from analyzing a created mixture of charged particles.
In Figure 4 below the results of analyzing a mixture of alpha and gamma Aluminas in 1 mMolar KCI at pH10 is displayed. The left peak is identified with the green cursor and shown to have a zeta potential of -20.54 mV. If the other peak is chosen the value given is -5.00 mV. The ability of the NanoBrook NanoBrook Omni to provide this information distinguishes it from other methods which provide only an ensemble average.
Something more challenging - PALS
Of course the NanoBrook Omni can quickly and easily yield results from all "regular" samples but its real strength is in the difficult cases and to demonstrate the performance of this premium instrument where others fail, we offer the follow table.
Multiple Sample Types
Table 1 below shows a variety of difficult to measure samples, all of which were easily measured with the NanoBrook ZetaPALS. Some were measured in high salt concentration; some in low dielectric constant non-polar solvents; and one in a viscous liquid.
Electrophoretic Mobilities Determined with the NanoBrook Omni
(units 10-8 m2 /V·s)
Sample PALS Result Lit. Value Comments NIST 1980 2.51 ± 0.11 2.53 ± 0.12 Electrophoretic mobility standard. Blood Cells -1.081 ± 0.015 -1.08 ± 0.02 Dispersed in physiological saline Fe2O3 0.013 ± 0.0015 N.A. Dispersed in dodecane TiO2 0.255 ± 0.010 N.A. Dispersed in toluene - not dried TiO2 0.155 ± 0.011 N.A. Dispersed in toluene - dried TiO2 -0.503 ± 0.0015 N.A. Dispersed in ethanol Casein -0.025 ± 0.002 N.A. Dispersed in PEG - viscous SiO2 -0.73 ± 0.04 N.A. Dispersed in 2.0 M KCl - High salt
Biological samples such as proteins, antibodies, peptides, DNA/RNA are easily denatured by electrical fields. Brookhaven's NanoBrook Omni can successfully measure the mobility of biological samples with typical voltages from 2 to 4 Volts. In Figure 3 above, Lysozyme was measured with 2.5 volts applied.
Aggressive solvents such as DMF, THF, DMSO, MEK, etc., are easily accommodated by the Brookhaven NanoBrook Omni system with the use of our special solvent resistant electrodes and glass sample cells. The extension of zeta potential measurements in the realm of such systems is just another standout property of the Brookhaven NanoBrook Omni.
Usual solvent? If your solvent is unusual then its dielectric constant is probably unknown. In this case our BI-870 Dielectric Constant Meter will quickly and accurately provide the information necessary for a zeta potential measurement.
Sizing: Globular proteins, nanoparticles, and small polymers as well as most colloidal-sized materials in any non-absorbing liquidZeta Potential: Proteins, nanoparticle, polymer and colloidal-sized materials, suspended in any non-absorbing liquid, with relative permittivity (dielectric constant) > 1.5 and viscosity < 30 cP.
Sizing: > 0.3 nm to 10 µm diameter, depending on refractive index and concentrationZeta potential: 1 nm to 100 µm, sample dependent
Mobility range 10-11 to 10-7 m2 /V*s Zeta potential range -500 mV to 500 mV, sample dependent Maximum sample conductivity
Sizing: unlimitedZeta potential: 220 mS/cm, covering saline and PBS solutions for proteins, sample dependent
Sizing: 1 to 3 mL disposable plastic, 50 µL disposable, 40 µL quartz flow cell, 10 µL quartz minimumZeta potential: 180 µL, 600 µL, 1250 µL
Sizing: 0.1 ppm to 50 mg/mL, depending on refractive index and concentrationZeta potential: 40% v/v, sample dependent
Sizing: Dynamic Light Scattering, DLSZeta potential: Electrophoretic & true Phase Analysis Light Scattering, ELS & PALS
Correlator Brookhaven's TurboCorr, multitau research grade with 510 hardware channels, covering the equivalent of 1010 linearly-spaced channels, 100% efficiency, real-time operation over the entire delay-time range Precision
Sizing: ± 1% typicalZeta Potential: ± 3% typical
Temperature Control -5 °C to 110 °C, ± 0.1 °C, active control. No external circulator required. Condensation Control Purge facility using dry air, nitrogen preferred Standard Laser 35 mW red diode laser, nominal 640 nm wavelength Scattering Angles 15°, 90°, and 173° Data Presentation
Average & width, lognormal fit, and multimodal size distribution standard.Doppler Frequency Shift, electrophoretic mobility, zeta potential using Smoluchowski, Hückel or Henry.
Compliance ISO 13321 and ISO 22412 compliant results Power Requirements 100/115/220/240 VAC, 50/60 Hz, 150 Watts Dimensions 23.3 x 42.7 x 48.1 (HWD in cm) Weight 15 kg Environmental Characterisitics
Temperature 10 °C to 75 °C
Humidity 0% to 95%, non-condensing
CE Certificate Class I laser product, EN 60825-1:2001 CDRH
Notes: * sample dependent
A policy of continual improvement may lead to specification changes.
Options for particle sizing at 90°
90PDP Absolute molecular weights of polymers in solution. Option includes 40 µL flow cell (90PFC) and Debye plot software, requires BI-APD. Relative molecular weight calculated from the DLS determination of the diffusion coefficient is standard. BI-PSD21 21 CFR Part 11 software to assist ERES compliance, sizing only. BI-IQOQPQ Qualification for installation, operation and performance for sizing and zeta. BI-SFS Sample filtration system provides fast and convenient way to clean your light scattering samples, a necessity for samples smaller than 20nm. Utilizing Teflon® tubing and nonreactive components, the BI-SFS is compatible with most sample filtration needs provided there is at least 5 mL of liquid. For protein and other rare samples, use 20 nm BI-DF20AQ Anatop filters instead. Lasers 5 and 10 mW, HeNe lasers at 632.8 nm wavelength. 50 mW and higher powered, frequency-doubled solid state lasers at 532 nm wavelength.
Accessories for particle sizing at 90°
Cells BI-RCG Box of 250 round glass cells with 25 reusable Teflon caps, 1.9 to 4 mL volume. Use with solvents, requires BI-RCH. BI-RCH One round cell holder for use with BI-RCH BI-SM50 Box of 80 plastic cells, disposable, 50 µL volume, sample retrievable, requires BI-SM50A. Use with water. BI-SM50A One sample cell adaptor for use with BI-SM50. BI-SM10 One 10 µL cell for sizing of small and rare samples, sample is retrievable. 90PFC Additional 40 µL quartz flow cell for use with 90PDP Reference Materials BI-LTX92 Latex reference material for validatino fos sizing, 15 mL, 92 ± 3 nm. BI-SVK92 Starters validation kid for sizing, 2 mL, 92 ± 3 nm. BI-CC Nitrogen-purge facility for condenstation control.
Options for zeta potential
BI-ZTU Autotitrator, 4-pump, pH, temp, conductance for use with acids, bases, surfactants, dispersing agents, salts and other additives to determine the IEP and trend of zeta potential with concentration of additive. BI-ZTU includes one BI-ZELF-P and one BI-ZELF-P/B for use with aqueous samples or BI-ZELF-G and one BI-ZELF-G/B for use in solvents. BI-ZELF-P Plastic electrode assembly for use with BI-ZTU in flow mode, including one BI-ZELF-P/B, for use in water. BI-ZELF-P/B Box of 2 plastic flow cells for use with BI-ZELF-P. Use in aqueous environments. BI-ZELF-G Solvent resistant electrode assembly for use with BI-ZTU in flow mode, including one BI-ZELF-G/B glass cell, for use in solvents. BI-ZELF-G/B Additional glass cell for use with BI-ZELF-G BI-870 Dielectric constant meter improves accuracy when calculating zeta potential in solvent mixtures and speciality solvents. BI-PALS21 21 CFR Part 11 software to assist ERES compliance.
Accessories for zeta potential
BI-SREL Solvent resistant electrode assembly for use with BI-SCGO glass cells, inconvenient for use with BI-SCP cells. BI-SCGO Box of 10, open-topped glass cells for use with solvents.When working in saline and other high salt concentrations use one of thse electrodes*: BI-ZEL Electrode assembly for aqueous systems, use BI-SCP cell, 1.25 mL sample volume. BI-ZEL2 Electrode assembly for aqueous systems, use BI-SCP cell, 450 µL sample volume. Or BI-SVE175 Electrode assembly for aqueous systems, with BI-SCP cell, 175 µL sample volume. BI-ELECCK Electrode cleaning kit including wand and polishing strip, for use with BI-ZEL and BI-SREL. BI-ZR5 Zeta reference material for validation, blue pigment for use in water, - (44 ± 8) mV.
*While it is tempting to buy just the solvent resistant electrode assembly and use it with the glass cells (BI-SCGO) in solvents and the plastic cell (BI-SCP) if measuring in saline or other aqueous environments, it is a mistake on two accounts. First, cross-contamination is a problem with small sample volumes such as those found in zeta potential determinations. Second, the solvent resistant assembly has to be small enough to clear the inside dimensions of the glass cells to prevent cracking. It is less convenient when removing the assembly and cells. But the standard BI-ZEL electrode can fit snugly into the BI-SCP cells and so both are convenient to remove when measuring in aqueous-based samples.
Note: Current users of the 90Plus PALS may upgrade to include backscatter provided their instrument has the necessary mechanics, optics and hardware. Contact hte factory for more information.