AccuSizer 7000 SIS Optical Particle Counter by Particle Sizing Systems

Overview

The AccuSizer 7000 SIS Optical Particle Counter is a high-precision, single-particle optical sensing (SPOS) instrument engineered for quantitative particle size distribution analysis and individual particle counting in liquid dispersions. Unlike ensemble-averaging techniques such as dynamic light scattering (DLS) or laser diffraction, the 7000 SIS detects and sizes each particle individually as it passes through a focused laser beam—enabling statistically robust, high-resolution quantification of low-abundance submicron and micron-scale particles. This principle aligns directly with the detection methodology specified in United States Pharmacopeia (USP) for subvisible particle testing in injectable pharmaceuticals and biologics. Its design emphasizes trace-level sensitivity, reproducibility across batch-to-batch analysis, and compliance-ready operation in regulated environments including QC laboratories operating under cGMP and GLP frameworks.

Key Features

• True single-particle detection via high-sensitivity photodiode array and calibrated laser optics, delivering direct count-based concentration data (particles/mL) alongside size distribution histograms.
• Modular, fully enclosed fluidic path with integrated auto-dilution system—eliminates operator-induced contamination, evaporation, and sampling bias associated with open-loop or manual syringe-based systems.
• Multi-range sensor configuration support: selectable detection thresholds from 0.5 µm to 2500 µm enable application-specific optimization without hardware replacement.
• Broad solvent compatibility: validated for aqueous buffers, saline solutions, ethanol, isopropanol, DMSO, and other common organic solvents used in formulation development and stability studies.
• Programmable syringe pump options (1–25 mL) allow precise control over sample volume and injection rate, supporting both low-volume precision assays and high-throughput industrial screening.
• Robust mechanical architecture with temperature-stabilized optical chamber and vibration-damped base minimizes signal drift and ensures long-term measurement stability.

Sample Compatibility & Compliance

The AccuSizer 7000 SIS accommodates samples ranging from purified water and protein therapeutics to polymer dispersions and nanoparticle suspensions. Its sealed flow path supports direct analysis of undiluted or pre-diluted samples, with automatic dilution capability for concentrated suspensions exceeding 10⁶ particles/mL. The system meets critical regulatory requirements for pharmaceutical quality control, including full alignment with USP and , ISO 21501-4 (calibration and verification of light-scattering particle counters), and ISO 13322-2 (SPOS method validation). When equipped with the 21 CFR Part 11-compliant software package, the instrument provides electronic signatures, audit trails, user access controls, and data integrity safeguards required for FDA-submitted analytical reports.

Software & Data Management

Data acquisition and analysis are performed using PSS’s proprietary AccuSizer software suite, compatible with Windows 10/11 platforms. The standard version offers real-time histogram generation, cumulative distribution plots (D10/D50/D90), particle concentration trending, and customizable reporting templates. The 21 CFR Part 11 edition adds role-based user authentication, immutable audit logs tracking all parameter changes and report exports, electronic signature workflows, and encrypted database storage. All raw pulse-height data files are retained in native format for retrospective reprocessing, ensuring full traceability and method flexibility during investigations or regulatory audits.

Applications

• Subvisible particle characterization in parenteral drug products per USP , including monoclonal antibodies, vaccines, and small-molecule injectables.
• Stability-indicating monitoring of particulate formation during accelerated and real-time shelf-life studies.
• Process validation and filtration efficiency assessment in biomanufacturing unit operations.
• Quality control of excipients, liposomes, lipid nanoparticles (LNPs), and polymeric micelles.
• Research-grade particle counting in academic and industrial colloid science labs requiring absolute number concentration and size resolution beyond ensemble methods.
• Environmental and industrial fluid cleanliness testing (e.g., hydraulic oils, coolants) per ISO 4406 or NAS 1638 standards.

FAQ

What is the fundamental difference between SPOS and laser diffraction?
SPOS measures each particle individually using light extinction or scattering, yielding absolute counts and high-resolution size bins; laser diffraction infers size distribution from ensemble scattering patterns and assumes spherical, homogeneous particles.
Can the AccuSizer 7000 SIS analyze opaque or highly viscous samples?
It requires optically transparent or semi-transparent dispersions with sufficient laser transmission; highly turbid or viscous samples (>50 cP) must be diluted or filtered prior to analysis.
Is calibration traceable to NIST standards?
Yes—PSS provides NIST-traceable polystyrene latex (PSL) and silica reference standards with certified mean diameters and uncertainty budgets, compliant with ISO 21501-4 Annex B.
Does the system support automated unattended operation?
With optional autosampler integration and scheduled run protocols, the 7000 SIS supports walk-away operation for multi-sample sequences in routine QC workflows.
How is data integrity ensured during software upgrades or system migration?
The 21 CFR Part 11 software enforces version-controlled backups, cryptographic hashing of raw data files, and migration validation reports that document file integrity pre- and post-transfer.