NanoBrook Series

  • NanoBrook Series

The NanoBrook Series size and zeta potential analyzers incorporate 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 or 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.

 

Rapid, Reliable, and Accurate Analysis

The NanoBrook Series particle size and zeta potential analyzers are 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. These instruments can also be configured with Phase Analysis Light Scattering (PALS) for samples with low mobilities or high conductivity measurements.

 

Three Possible Scattering Angles

Measurements of colloids are traditionally made using a 90° scattering angle. For smaller nanoparticles, proteins including IgG, mAbs, and peptides, these < 50 nm samples can be measured using the backscattering angle (173°). 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.

 

The NanoBrook Omni combines all of the most common configurations

With the NanoBrook Omni, measure samples in nearly every possible suspension environment from high salts such as PBS and sea water to organic solvents and aqueous solutions. Particle and protein sizing, with the highest sensitivity, utilize three measurement angles for truly unbiased measurement results.

Overview

Rapid, Reliable, and Accurate Analysis

Characterizing proteins, nanoparticles, and polymers confronts the user with a difficult choice of instrumentation. Brookhaven Instruments makes that choice easier with the NanoBrook series of instruments. Choose from particle sizing including backscatter for proteins, Zeta Potential, or combinations including molecular weight determination of small polymers and proteins.

Measurement Principles

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 cases, just a few minutes are required for the sample and cell to equilibrate with the actively controlled temperature environment inside the NanoBrook.

 

Data Presentation

 

image of DLS report
Figure 1

 

The NanoBrook particle size and zeta potential analyzer offer 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 Figure 1 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.

 

image of bimodal test resultsFigure 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

 

Phase Analysis Light Scattering

For measurements of very low mobilities, the Brookhaven NanoBrook is the answer; the only answer! With concepts developed at Bristol University and Brookhaven Instruments, the NanoBrook 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. Such measurements cover the range of typically ± (6 to 100) mV, corresponding to mobilities of ± 0.5-8×10-8 m2 /Vs. The NanoBrook covers this full range, of course, and extends it by a factor of 1000 in sensitivity!

 

Principles of Operation – Zeta Potential

The NanoBrook 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 because the measurement analyzes the phase shift. The particles need only to move a fraction of their 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.

 

image of test resultsFigure 3

 

Simple and clear presentation

Figure 3 above shows the results of an actual experiment with a NanoBrook 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 the experimental curve (red, bold) and its fitted version (red, thin). As with all Brookhaven instruments the user can simply produce a customized report.

 

Custom Columns

The software can be easily customized to display the columns needed for a quick review of the important parameters as shown below.

 

image of custom columns

 

 

Comprehensive Information – ELS

The NanoBrook measures complete electrophoretic mobility distributions in seconds including multimodals. An example of a 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 molar KCI at pH10 are 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 to provide this information distinguishes it from other methods which provide only an ensemble average.

 

image of results of analyzing a mixture of alpha and gamma Aluminas in 1 mMolar KCI at pH10
Figure 4

 

Something more challenging – PALS

Of course, the NanoBrook 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 following table.

 

Multiple Sample Types

Table 1 below shows a variety of difficult-to-measure samples, all of which were easily measured with the NanoBrook. Some were measured in high salt concentration; some in low dielectric constant non-polar solvents; and some in a viscous liquid.

 

Electrophoretic Mobilities Determined with the NanoBrook Omni
(units 10-8 m2 /V·s)
SamplePALS ResultLit. ValueComments
NIST 19802.51 ± 0.112.53 ± 0.12Electrophoretic mobility standard.
Blood Cells-1.081 ± 0.015-1.08 ± 0.02Dispersed in physiological saline
Fe2O30.013 ± 0.0015N.A.Dispersed in dodecane
TiO20.255 ± 0.010N.A.Dispersed in toluene – not dried
TiO20.155 ± 0.011N.A.Dispersed in toluene-dried
TiO2-0.503 ± 0.0015N.A.Dispersed in ethanol
Casein-0.025 ± 0.002N.A.Dispersed in PEG – viscous
SiO2-0.73 ± 0.04N.A.Dispersed in 2.0 M KCl – High salt

 

 

Biological samples such as proteins, antibodies, peptides, and DNA/RNA are easily denatured by electrical fields. Brookhaven’s NanoBrook 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 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.

 

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.

 

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:

 

image of surface zeta potential

 

μRhe

Simple fluids like water (low viscosity), and 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 particles 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.

Typical Applications

Typical Applications Include:

  • Proteins, IgG, peptides, RNA/DNA
  • Liposomes, exosomes, and other biocolloids
  • Polysaccharides
  • Nanoparticles
  • Polymer latexes
  • Pharmaceutical preparations
  • Micelles
  • Oil/Water and Water/Oil emulsions
  • Paints and pigments
  • Colloids
  • Polymers
  • Pigments, inks and toners
  • Cosmetic Formulation
  • Ceramics and refractories
  • Emulsions (foodstuffs, cosmetics)
  • Wastewater treatment monitoring
  • Carbon blacks

Options & Accessories

Accessories for particle sizing

Cuvettes

BI-SCP100 plastic cells/caps for use with water and simple polar liquids, sample volume from 2.2 mL to 4 mL
BI-SCGOBox of 10 open glass square cells for use with BI-SREL electrode
BI-SM50ASmall volume cell adaptor: Required for BI-SM50.
BI-SM1010 mL square quartz cell for particle sizing of small volume samples
BI-RCHRound cell holder insert: Required for BI-RCG.
BI-RCGBox of 250 round glass cells with 25 reusable Teflon caps, sample volume from 1.9 mL to 4 mL: Requires BI-RCH.

Standards

BI-SVK92Particle size validation kit, (92 +/- 3 nm)
BI-LTX92Latex reference material, (92 +/- 3 nm)

Accessories for zeta potential

Cuvettes

BI-SCGOBox of 10 open glass square cells for use with BI-SREL electrode

Reference Materials

BI-ZR5Zeta potential reference material, – (44 ± 8) mV

Spares (electrodes)

BI-SRELElectrode assembly for nonpolar liquids: Requires ZetaPALS. Use BI-SCGO cells.
BI-SVE175Electrode assembly for aqueous systems, with BI-SCP cell, 175 µL sample volume.
BI-ELECCKElectrode cleaning kit including wand and polishing strip, for use with BI-ZEL and BI-SREL.
BI-SZPSurface Zeta Potential electrode assembly for aqueous systems

Note: Current users of the 90Plus PALS may upgrade to include backscatter provided their instrument has the necessary mechanics, optics, and hardware. Contact us for more information.

Download Brochures

Available Downloads 

 

NanoBrook Series

NanoBrook Series Brochure – Particle Sizing and Zeta Potential Analysis PDF

 

NanoBrook Configurations

NanoBrook Omni Brochure PDF

NanoBrook 90Plus Brochure PDF

NanoBrook 90Plus PALS Brochure PDF

NanoBrook 90Plus Zeta Brochure PDF

NanoBrook ZetaPALS Brochure PDF

NanoBrook ZetaPlus Brochure PDF

NanoBrook 173 Brochure PDF

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