CORDOUAN Arago ε / ω / ∞ Precision Digital Refractometer
| Origin | France |
|---|---|
| Manufacturer Type | Authorized Distributor |
| Origin Category | Imported Instrument |
| Model Series | Arago ε, Arago ω, Arago ∞ |
| Product Type | Benchtop Refractometer |
| Temperature Control | Peltier-regulated (15–65 °C for ε |
| Digital Display | Yes (high-resolution capacitive touchscreen + PC interface) |
| Refractive Index Range (nD) | 1.25–1.51 or 1.51–1.75 (ε) |
| Resolution (nD) | ±0.00001 (ε, ω), ±0.000001 (∞) |
| Accuracy (nD) | ±0.0001 (ε), ±0.00005 (ω), ±0.00001 (∞) |
| Wavelength | 635 nm (ε), 658 nm (ω, ∞) |
| Prism Material | BK7 glass (ε), fused silica (ω), sapphire (∞) |
| Sample Cell Material | 316 stainless steel or Inconel® alloy (optional) |
| Brix Range | 0–95 % w/w |
| Brix Accuracy | ±0.002 % |
| Repeatability | ±0.01 % |
| Light Source | Integrated temperature-stabilized laser diode |
| Dimensions (W×D×H) | 10 × 24 × 27 cm |
| Weight | 8 kg |
| Interface | USB 2.0 (bidirectional PC communication) |
| Power Supply | 100–240 V AC, 50/60 Hz |
Overview
The CORDOUAN Arago ε / ω / ∞ series represents a class of high-precision benchtop digital refractometers engineered for metrological-grade refractive index (nD) measurement in demanding industrial and research laboratories. Based on the principle of critical angle determination at the sample-prism interface—governed by Snell’s law—the instrument delivers absolute nD values traceable to NIST-certified reference standards. Unlike traditional Abbe-type refractometers, the Arago platform employs collimated laser illumination (635 or 658 nm), real-time Peltier temperature stabilization, and an optically optimized prism assembly to eliminate thermal drift and minimize angular uncertainty. Its design enables direct measurement of highly absorbing, viscous, or volatile liquids—including dark hydrocarbons, concentrated pharmaceutical solutions, and thermally sensitive fragrances—without dilution or pre-treatment. The system operates under ISO 5725-defined repeatability protocols and complies with ASTM D1218, ISO 2859, and USP refractometry guidelines for quality control applications.
Key Features
- Three-tiered model architecture (ε, ω, ∞) optimized for distinct nD ranges and resolution requirements—from routine QC (ε) to ultra-high-accuracy R&D (∞)
- Peltier-controlled thermostatic chamber with programmable setpoints (15–65 °C for ε; 15–80 °C for ω/∞) and stability ≤ ±0.02 °C over 30 min
- Modular prism systems: BK7 (ε), fused silica (ω), and single-crystal sapphire (∞) for extended spectral durability and chemical inertness
- Sample cell constructed from electropolished 316 stainless steel or optional Inconel® 625 for resistance to halides, strong acids, and high-temperature organics
- Integrated laser safety interlock: automatic beam shutoff during lid opening per IEC 60825-1 Class 1 compliance
- Capacitive touchscreen interface with multilingual OS (English/French), local data logging (≥10,000 measurements), and GLP-compliant audit trail
- Zero-crossing optical detection algorithm eliminating Fresnel approximation error—critical for low-reflectivity or high-nD samples (e.g., molten polymers, heavy oils)
- Minimal sample volume requirement: 0.5–1.2 mL depending on viscosity and surface tension
Sample Compatibility & Compliance
The Arago series accommodates challenging matrices that exceed conventional refractometer limitations. Its sapphire prism (Arago ∞) supports nD up to 3.10—enabling characterization of silicones, optical resins, molten salts, and semiconductor process fluids. Volatile solvents (e.g., hexane, acetone) are measured under temperature-stabilized, sealed-cell conditions to prevent evaporation-induced drift. For food-grade applications, the system meets FDA 21 CFR Part 11 requirements when paired with CORDOUAN’s validated software suite, including electronic signatures, user access levels, and immutable data export (CSV, PDF, XML). All models are CE-marked and conform to EN 61326-1 (EMC) and EN 61010-1 (safety) standards. Calibration verification follows ISO/IEC 17025 procedures using certified sucrose and bromonaphthalene standards.
Software & Data Management
CORDOUAN’s AragoControl™ software provides full instrument orchestration via USB connection. It supports method-based workflows compliant with GMP/GLP environments—including parameter locking, calibration certificate generation, and automated pass/fail reporting against configurable specification limits (e.g., IP 357 for lubricants, AOAC 932.12 for honey). Raw angular data, temperature logs, and refractive index traces are timestamped and stored with metadata (operator ID, sample ID, ambient RH). Export formats include CSV (for LIMS integration), PDF reports with digital signature fields, and XML for ERP synchronization. Audit trails record all configuration changes, calibration events, and user logins—fully compliant with FDA 21 CFR Part 11 Annex 11 requirements. Remote firmware updates and diagnostic telemetry are supported through secure HTTPS channels.
Applications
- Petroleum & Petrochemicals: nD profiling of naphtha fractions, jet fuels (ASTM D1298), styrene monomer purity, and aromatic solvent blends (benzene/toluene/xylene)
- Foods & Beverages: Brix quantification in fruit juices (AOAC 932.12), honey adulteration screening (ISO 21542), edible oil classification (olive vs. sunflower via nD at 20 °C), and syrup solids content verification
- Pharmaceuticals & Cosmetics: Excipient concentration monitoring (propylene glycol, glycerin), fragrance oil batch release testing, and active ingredient assay in liquid dosage forms
- Chemical Manufacturing: Real-time reaction endpoint detection in esterification, polymerization, and halogenation processes where nD correlates with conversion
- Academic Research: Thermodynamic property modeling (excess molar refraction), binary mixture phase behavior, and nanoparticle dispersion stability assessment
FAQ
What is the difference between Arago ε, ω, and ∞ models?
The ε model targets general-purpose QC with 1.25–1.51 or 1.51–1.75 nD range and ±0.0001 accuracy; ω extends the lower limit to 1.20 and improves resolution to ±0.00005; ∞ achieves ultra-wide 1.20–3.10 coverage and sub-ppm resolution (±0.000001) using sapphire optics.
Can the Arago measure opaque or deeply colored samples?
Yes—its critical-angle detection method is insensitive to sample absorption, enabling reliable measurement of black oils, caramelized syrups, and iodine-containing pharmaceuticals without filtration or dilution.
Is temperature calibration traceable to national standards?
Yes—each unit ships with a factory calibration certificate referencing NIST-traceable thermostats and certified reference liquids (e.g., bromonaphthalene, n-hexadecane), valid for 12 months under recommended maintenance.
Does the system support automated cleaning cycles?
No—cleaning is manual but facilitated by the smooth, crevice-free sample cell geometry and chemical-resistant materials; CORDOUAN recommends ethanol or isopropanol rinses between samples.
How is data integrity ensured during regulatory audits?
Through hardware-enforced write-once storage, time-stamped audit logs, role-based access control, and cryptographic hash validation of exported reports—fully aligned with ALCOA+ principles.
