Particle Size Analyzer

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Features at a glance Rapid and accurate particle size distributions Multimodal and unimodal size distribution software Range <1 nm to 6 m 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, complete with printer Optional zeta potential modules available FOQELS module for sizing in concentrates available Molecular weight determination

Rapid, Reliable and Accurate Analysis

The new 90Plus particle sizer 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. The built-in PC computer has ample power for the Windows-based software. 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 L or less. For aqueous samples this sample volume may be reduced to 50 L with a new option , in both cases the sample is recoverable . For very small particles the high-sensitivity BI-APD detector is invaluable.

Reproducibility
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.

The following table shows several aspects of the inter-instrument repeatability found with routine BIC dynamic light scattering equipment. To test the reliability of the information obtained with BIC instruments a customer subjected five instruments in five locations with different operators and 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 90Plus!

Test Results from BIC Particle Sizers (diameters, in nm)

Data Presentation
The 90Plus 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

Typical Applications

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 Formulations

Specifications

Size Range: <1 nm to 6 m depending on refractive index, concentration and scattering angle.
Precision: 1% typically.
Sample Type: Most colloidal-sized materials, suspended in any clear liquid.
Sample Volume: 1 to 3 mL. New: 10 L small-volume cells.
Temperature Control: 6 C to 100 C, 0.1 C, active control. No external circulator required.
Laser: 35 mW, solid state, standard. See options.
Scattering Angles: 15 & 90.
Data Presentation: Average & width, lognormal fit, and multimodal size distribution standard.
Correlator: Brookhaven 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: Built-in PC. Windows Software included. Check with factory for latest specifications. External computer optional.
Printer: Color inkjet, standard. Others available.
Monitor: LCD.

Power Requirements:
100/115/220/240 VAC, 50/60 Hz, 300 Watts.

Dimensions:(excluding monitor and printer)
267(H) x 625(W) x 445(D) in millimeters.

Weight:(excluding monitor and printer)
37 kg.

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

A policy of continued improvement may lead to specification changes

 Marked

Options and Accessories

BI-Zeta: Adding the BI-Zeta option to the 90Plus allows the user to study both zeta potential and particle size in the same instrument. The sign and magnitude of zeta potential, as a function of pH, surfactant, salt or dispersing agent concentration are indicators of the surface properties of materials. Zeta potential is a measure of the repulsive forces in electrostatically stabilized systems, and, therefore, a measure of relative stability to change. High values - either positive or negative - signify stability; whereas, values approaching zero signify instability; typically either flocculation or coagulation. Applications include waste water treatment and stability of pigments, latexes, ceramics, and other colloidal dispersions. With the BI-Zeta option added, the 90Plus instrument acquires all of the functionality of the Brookhaven ZetaPlus instrument.

BI-PALS: Zeta potential determinations in organic solvents, viscous oils, high salt concentrations or very near the isoelectric point require a very sensitive detection technique. In these cases, add the BI-PALS option to the BI-Zeta. The PALS technique of Phase Analysis Light Scattering is up to 1,000 times more sensitive than traditional light scattering techniques based on the shifted frequency spectrum (Doppler shift) and is available only from BIC . With the BI-PALS option added, the 90Plus instrument acquires all the functionality of the Brookhaven ZetaPALS instrument.

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

BI-PSD21: 21 CFR Part 11 compliant software

90PDP: Molecular weights of polymers in solution. Includes 40 L flow cell and Debye plot software.

BI-SFS: The new BI-SFS sample filtration system provides a 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. Its modular design allows users to change pump heads and speeds to encompass virtually any possible application.