4000 Series Monosized Beads Suspension (1 µm–160 µm)

4000 Series Monosized Bead Suspensions

The 4000 Series consists of spherical polymer particle-size standards for applications requiring high size uniformity and narrow size distributions.

Spherical microspheres reduce shape-related measurement effects commonly associated with irregular dusts and mineral particles. Their uniform geometry supports clean, reproducible instrument response peaks and reduces orientation-dependent scattering artifacts.

Each standard is calibrated using linear dimensions traceable to the National Institute of Standards and Technology (NIST). Calibration may use optical microscopy, transmission or scanning electron microscopy (TEM/SEM), or electrical resistance analysis based on the Coulter principle.

The particles are supplied in 15 mL dropper bottles containing an ultra-clean aqueous medium designed for stable dispersion and low background interference.

Key features

• NIST traceability: Particle diameters are calibrated against NIST Standard Reference Materials and documented with lot-specific Certificates of Calibration and Traceability.
• Monodisperse size distribution: Typical coefficients of variation range from below 3% to below 5%.
• Reduced shape effects: Spherical geometry minimizes orientation bias and irregular light scattering.
• Dropper dispensing: The 15 mL dropper bottle allows controlled addition to fluid reservoirs, sample cuvettes, and nebulizers.
• Broad size range: Discrete calibrated sizes from 1 µm to 160 µm support liquid particle counters, flow cytometers, microscopes, and related systems.

Specifications

Part numbers and variants

All products are supplied as aqueous suspensions in 15 mL dropper bottles.

For every listed product:

• Form: Aqueous suspension
• Package: 15 mL dropper bottle
• Material: Monodisperse polystyrene/polymer microspheres

Applications

• Optical and liquid particle counter calibration: Set size-channel thresholds, detection limits, and optical resolution.
• Laser diffraction and dynamic light scattering: Verify scattering algorithms, angular response, and instrument precision.
• Microscope stage and reticle calibration: Calibrate ocular micrometers, stage graticules, and automated image-analysis systems.
• Flow cytometry alignment: Check hydrodynamic focusing, laser alignment, and forward- and side-scatter channels.
• Biological particle analogues: Provide reference-size surrogates for bacteria, red blood cells, spores, and cellular organelles.

Handling and storage

• Store upright at 4∘C to 30∘C in a tightly closed container.
• Do not freeze. Freezing can damage the suspension medium and cause irreversible agglomeration.
• Before dispensing, gently invert the bottle 10 to 15 times or slowly roll it.
• If particles have settled, place the bottle in a mild ultrasonic bath for 10 to 20 seconds.
• Dispense from the clean dropper tip directly into the diluent or measurement reservoir.
• Avoid touching the dropper tip to nonsterile surfaces or liquid samples to prevent cross-contamination.