Brookhaven Instruments 90Plus PALS Zeta Potential and Particle Size Analyzer
| Origin | USA |
|---|---|
| Manufacturer Type | Authorized Distributor |
| Origin Category | Imported |
| Model | 90Plus PALS |
| Price Range | USD $12,500 – $37,500 |
| Zeta Potential Range | −500 to +500 mV |
| Particle Size Range | 0.3 nm – 6 μm |
| Electrophoretic Mobility Range | 1×10⁻¹¹ to 1×10⁻⁷ m²/V·s |
| Conductivity Range | 0–30 S/m |
| Temperature Control | −5 °C to 110 °C (±0.1 °C) |
| Laser Source | 35 mW Solid-State Diode Laser |
| Detection | PMT or APD |
| Scattering Angles | 15° and 90° |
| Correlator | 4×522 physical channels, 4×10¹¹ linear channels |
| Electrode | Open-configuration permanent palladium electrode |
| Sample Volume (Zeta) | 0.18–1.5 mL |
| Sample Volume (Size) | 1–3 mL |
| pH Measurement Range | 1–14 |
| Molecular Weight Range | 342–2×10⁷ Da |
| Software | Particle Solution™ v5.x (GLP-compliant with audit trail, electronic signature support per 21 CFR Part 11) |
Overview
The Brookhaven Instruments 90Plus PALS Zeta Potential and Particle Size Analyzer is a dual-mode, high-sensitivity instrument engineered for simultaneous and independent characterization of colloidal stability and hydrodynamic size distribution in complex dispersions. At its core lies Phase Analysis Light Scattering (PALS), a proprietary electrophoretic light scattering technique developed by Brookhaven Instruments that measures phase shifts—rather than frequency shifts—in scattered laser light induced by particle motion under an applied electric field. This fundamental distinction delivers up to three orders of magnitude higher sensitivity in electrophoretic mobility detection compared to conventional Laser Doppler Velocimetry (LDV) or Frequency Modulation (FM) methods. As a result, the 90Plus PALS reliably quantifies zeta potential in challenging systems where traditional analyzers fail: low-dielectric solvents (e.g., ethanol, THF), highly viscous media (e.g., polymer melts, glycerol-based formulations), high-ionic-strength electrolytes (≥1 M NaCl), and near-isoelectric conditions where mobility drops below 1×10⁻⁹ m²/V·s. The system integrates dynamic light scattering (DLS) and static light scattering (SLS) capabilities using a dual-angle (15° and 90°) detection geometry, enabling robust size analysis across the sub-nanometer to micrometer range and absolute molecular weight determination via Debye plot analysis.
Key Features
- Patented PALS technology with phase-resolved detection—enabling accurate zeta potential measurement down to ±1 mV resolution even for low-mobility particles
- Dual-angle optical configuration (15° and 90°) optimized for polydisperse samples and refractive index variability
- Thermostatically controlled cuvette chamber with ±0.1 °C stability over −5 °C to 110 °C, supporting kinetic studies and temperature-dependent stability profiling
- Open-configuration, corrosion-resistant palladium electrodes—designed for long-term reliability in aggressive chemical environments and eliminating cell replacement costs
- High-dynamic-range correlator with 4 independent input channels and 4×10¹¹ linear channels—supporting multi-angle cross-correlation and advanced noise rejection algorithms
- Modular hardware architecture compatible with optional accessories including the BI-ZTU automated titrator, BI-870 dielectric constant analyzer, and BI-SV10 capillary viscometer for full physicochemical parameterization
- Laser source options: 35 mW solid-state diode laser (standard) or 5 mW He-Ne laser (optional, for UV-sensitive or fluorescence-prone samples)
Sample Compatibility & Compliance
The 90Plus PALS accommodates a broad spectrum of colloidal and macromolecular systems without requiring dilution or extensive sample preparation. Validated applications include liposomes, protein aggregates, polymeric nanoparticles, ceramic slurries, pigment dispersions, latex emulsions, carbon black suspensions, and wastewater colloids. Its open electrode design permits direct measurement of opaque, viscous, or conductive samples—including those containing surfactants, organic solvents, or high salt concentrations—that would otherwise foul sealed electrophoresis cells. From a regulatory standpoint, the instrument meets essential requirements for quality-controlled environments: Particle Solution™ software supports 21 CFR Part 11 compliance with role-based access control, full electronic audit trails, user authentication, and tamper-proof data archiving. Method validation protocols align with ISO 13321 (DLS), ISO 22412 (PALS), and USP and guidelines for subvisible particle characterization in pharmaceuticals. All thermal, optical, and electrical subsystems undergo factory calibration traceable to NIST standards.
Software & Data Management
Particle Solution™ v5.x is the native analysis platform for the 90Plus PALS, providing integrated workflows for DLS, SLS, and PALS data acquisition, modeling, and reporting. The software implements advanced algorithms—including CONTIN, NNLS, and regularization-based distribution analysis—for resolving multimodal size distributions and distinguishing true polydispersity from instrumental artifacts. Zeta potential data are processed using Smoluchowski or Hückel models with automatic dielectric constant and viscosity correction based on user-input or BI-870/BI-SV10 accessory measurements. All raw correlator data, instrument parameters, and metadata are stored in a secure SQLite database with time-stamped entries. Reporting modules generate PDF/CSV outputs compliant with GLP and GMP documentation requirements, including method ID, operator ID, calibration history, and uncertainty estimation per ISO/IEC 17025. Remote monitoring and batch processing are supported via Ethernet interface and optional LabVIEW or Python API integration.
Applications
- Formulation development of lipid nanoparticles and mRNA delivery vectors—correlating surface charge modulation with cellular uptake efficiency (per JACS 2021, 143, 12072–12081)
- Stability assessment of ceramic and metal oxide slurries in CMP (Chemical Mechanical Polishing) slurries under variable pH and ionic strength
- Quality-by-Design (QbD) control of biopharmaceutical colloids—including monoclonal antibody aggregates and virus-like particles—across manufacturing scales
- Environmental colloidal science: quantifying charge reversal and aggregation kinetics of microplastics and humic acid complexes in natural waters
- Functionalized nanomaterial optimization: mapping isoelectric point shifts across amine/carboxyl ratio gradients in gold nanoparticle conjugates
- Food and cosmetic emulsion engineering: linking zeta potential hysteresis to creaming rate and Ostwald ripening behavior
FAQ
What distinguishes PALS from conventional electrophoretic light scattering techniques?
PALS measures the phase shift—not frequency shift—of modulated scattered light, enabling direct quantification of particle velocity with significantly improved signal-to-noise ratio and immunity to low-frequency electrical noise.
Can the 90Plus PALS measure zeta potential in organic solvents such as acetone or chloroform?
Yes—provided the solvent’s dielectric constant and conductivity fall within the instrument’s operational envelope (εᵣ ≥ 2; σ ≤ 30 S/m). Optional BI-870 dielectric constant verification is recommended for method transfer.
Is temperature control available during zeta potential measurement?
Yes—the integrated Peltier system maintains sample temperature from −5 °C to 110 °C with ±0.1 °C accuracy throughout both size and zeta acquisition cycles.
Does the system support automated pH titration for isoelectric point mapping?
When paired with the BI-ZTU automatic titrator, the 90Plus PALS executes programmable pH, conductivity, or additive concentration ramps while synchronously acquiring zeta and size data.
How is data integrity ensured for regulated pharmaceutical use?
Particle Solution™ includes full 21 CFR Part 11 functionality: electronic signatures, session locking, immutable audit logs, and password-protected method templates—all validated per IQ/OQ protocols supplied with the system.
