Brookhaven - NanoBrook 90Plus Molecular Weight Analyzer

Nanobrook 90Plus

Molecular Weight Analyzer

Features at a glance

Rapid and accurate particle size distributions

Multimodal & unimodal size distribution software

Range < 1 nm to 6 µm

Easy to use Windows™ software

Customizable reports, SPC charts

Ideal for fast, routine sizing applications in research or quality control

High power 35 mW diode laser

Dynamic light scattering at 90° and 15°

Compact bench top unit

Optional zeta potential modules available

FOQELS module for sizing in concentrates available

Molecular weight determination

Rapid, Reliable and Accurate Analysis

The new 90Plus Particle Size Analyzer incorporates all you need for fast, routine, sub micron measurements. Based on the principles of Dynamic Light Scattering (DLS), most measurements only take a minute or two. Choose from the standard 35 mW laser for strong scatterers, or the avalanche photo diode for weak scatterers. And, at the time of manufacture, or as a future upgrade, add the BI-Zeta option for zeta potential measurements.

Two Scattering Angles:

Most measurements will be made at the 90° scattering angle, however, the user may select the 15° detection angle where measurements are more sensitive to larger particles.

Principles of Operation

Dilute suspensions, on the order of 0.0001 to 1.0% v/v are prepared, using suitable wetting and/or dispersing agents. A small ultrasonicator is sometimes useful in breaking up loosely-held agglomerates. Two or three mL of suspension are required to make the measurements. Disposable, acrylic square cells are used for aqueous and simple alcohol suspensions. Disposable, glass round cells with reusable Teflon stoppers are used for aggressive solvent suspensions. Just a few minutes are required for the sample and cell to equilibrate with the actively controlled temperature environment inside the 90Plus. A square glass cell is available if desired and a special small-volume cell may be used to reduce the volume of material needed to just 150 µL or less. For aqueous samples this sample volume may be reduced to 50 µL with a new option , in both cases the sample is recoverable. For very small particles the high-sensitivity BI-APD detector is invaluable.


90Plus Narrow Latex

Perhaps the most important benefit for users is the reproducibility from sample-to-sample, operator-to-operator, and instrument-to-instrument. The figure 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.

Data Presentation

The 90Plus Particle Size 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 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.

Results from Test Bimodal Sample on 90Plus (diameters, in nm)

The figure 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 98 and 270 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

Statistical Process Control

At the heart of process and quality control is the ability to measure, record, and track changes using statistical analysis. With the 90Plus, this procedure is now straightforward. Individual files, stored in user-defined folders, are simply marked for inclusion in a SPC chart. Files can be sorted by date/time or batch numbers. An SPC chart is automatically constructed using the mean and +/- 3 sigma (Std. Error) for the upper and lower control limits (UCL/LCL).

Alternatively, the user may select the mean and limits based on prior experience.

The Windows™-based software in the 90Plus allows the user to export the SPC chart into their favorite program. Of course, a direct printout is also available. The figure below shows a typical SPC chart for 18 runs. For this particular material the limits were manually set at 2 nm from the mean.

SPC Chart Display Selected on 90Plus

90PSPC 500px

Many everyday industrial processes and products involve dispersions. The dispersed phase is often in a state of fine subdivision. The technology to produce these dispersions, to ensure that they perform according to specifications and to solve problems which may arise in production or use, requires a knowledge of the particle size. The 90Plus can handle virtually any type of submicron sample suspended in, or dissolved in, a liquid. Some examples are

Polymer latexes

Pharmaceutical preparations

Oil/Water and Water/Oil emulsions

Paints and pigments

Inks and toners

Cosmetic Formulation

Size Range: 1 nm to 6 µm depending on refractive index, concentration & scattering angle

Precision: ± 1% typically

Sample Type: Most colloidal-sized materials, suspended in any clear liquid

Sample Volume: 1 to 3 mL. New: 10 µL small-volume cells

Temperature Control: -5 °C to 110 °C, ± 0.1 °C, active control. No external circulator required

Laser: 35 mW, solid state, standard

Scattering Angles: 15° & 90°

Data Presentation: Average & width, lognormal fit, and multimodal size distribution standard

Correlator: Brookhaven's TurboCorr, multitau, research grade with 510 channels, covering the equivalent of 1010 linearly-spaced channels, 100% efficiency, real-time operation over the entire delay-time range

Computer: External PC; now Windows 7 compatible

Power Requirements: 100/115/220/240 VAC, 50/60 Hz, 150 Watts

Dimensions: 23.3 x 42.7 x 48.1 cm (HWD)

Weight: 15 kg

Environmental Characteristics: Temperature 10 °C to 75 °C Humidity 0% to 95%, non-condensing

Certificates: CE Certified


BI-APD: Avalanche photo diode, up to 10 times the sensitivity

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.

BI-IQOQPQ: Qualification for installation, operation and performance.

BI-SFS: Sample filtration system provides fast and convenient way to clean your light scattering samples, a necessity for samples smaller than 20 nm. 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 or 10 mW, HeNe lasers at 632.8 nm wavelength, 50 mW and higher powered, frequency-doubled solid state lasers at 532 nm wavelength



BI-SCP: Box of 100 plastic cells with caps, 2.2 to 4.5 mL volume. Use with water.

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 quartz 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 refernece material for validation of sizing, 15 mL, 92 ± 3 nm.

BI-SVK92: Starters validation kit for sizing, 2 mL, 92 ± 3 nm.

BI-CC: Nitrogen-purge facility for condensation control.

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

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