ATAGO RX-7000i Benchtop Wide-Range Digital Refractometer

Overview

The ATAGO RX-7000i is a high-precision benchtop digital refractometer engineered for laboratories requiring broad-range, repeatable refractive index and Brix measurements across diverse sample matrices—from highly concentrated syrups and polymer solutions to low-concentration aqueous formulations. Unlike traditional Abbe-type refractometers, the RX-7000i employs a temperature-compensated LED light source coupled with a high-resolution CCD linear image sensor to perform real-time critical angle detection via total internal reflection. This optical architecture enables direct, non-destructive measurement of refractive index (n_D) at 589.3 nm (sodium D-line equivalent), automatically converted to Brix (%) using built-in polynomial calibration curves traceable to NIST-certified sucrose standards. The instrument operates without integrated Peltier temperature control; instead, it relies on precise ambient temperature monitoring (±0.1 °C resolution) and applies algorithmic compensation per ISO 21748 guidelines—ensuring metrological integrity when used within its specified ambient range (−10 °C to +55 °C). Its wide 0.00–100.00% Brix-equivalent measurement span accommodates undiluted industrial fluids, battery electrolytes, antifreeze concentrates, and pharmaceutical excipient solutions where conventional 0–85% instruments reach saturation.

Key Features

• High-resolution digital measurement with ±0.000100 refractive index accuracy (n_D), validated against certified reference materials.
• Broad dynamic range: 0.00–100.00% Brix-equivalent scale—enabling direct analysis of saturated sugar solutions, glycol-based coolants, and high-viscosity resins without dilution.
• Multi-mode operation (MODE-1, MODE-2, MODE-3, MODE-S) supporting simultaneous display of refractive index (n_D), Brix (%), and user-defined concentration units—including custom calibration tables for non-sucrose solutes (e.g., NaCl, ethylene glycol, propylene glycol).
• Large backlit LCD interface with intuitive menu navigation, real-time temperature readout, and on-screen data logging status indicator.
• Robust aluminum-alloy chassis and vibration-damped optical base ensure long-term stability in QC labs and production environments.
• Compliant with international standard methodologies: ASTM D1218 (petroleum products), ISO 21748 (uncertainty estimation for refractometry), and JIS K 0061 (Japanese Industrial Standard for refractometer verification).

Sample Compatibility & Compliance

The RX-7000i accepts liquid, semi-liquid, and low-turbidity colloidal samples via standard prism contact (25 mm × 25 mm sapphire prism surface). It supports aqueous, organic, and mixed-solvent systems with refractive indices between 1.3200 and 1.5600. Samples must be free of suspended particulates >5 µm to avoid scattering artifacts. While not designed for volatile or highly corrosive media (e.g., concentrated HF, fuming nitric acid), it handles ethanol-water blends, citric acid solutions, urea formulations, and food-grade oils within defined safety limits. All measurement protocols align with GLP documentation requirements: each result includes timestamp, operator ID (via optional USB keyboard input), ambient temperature, and mode selection—supporting audit-ready record retention under FDA 21 CFR Part 11 when integrated with compliant LIMS or ELN platforms.

Software & Data Management

Data export is supported via RS-232C serial interface (standard) or optional USB-to-serial adapter. Raw output includes n_D, %Brix, temperature (°C), measurement mode, and date/time stamp in ASCII format—compatible with Excel, LabVIEW, and industry-standard SCADA systems. ATAGO’s optional “Refractometer Manager” PC software (v3.2+) enables batch report generation, statistical process control (SPC) charting (X̄/R charts), and calibration history tracking with electronic signature capability. Audit trails log all parameter changes, calibration events, and user actions—meeting ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate, Complete, Consistent, Enduring, Available) for regulated environments.

Applications

• Food & Beverage: Direct Brix quantification of honey, maple syrup, fruit concentrates, and fermentation broths without dilution.
• Chemical Manufacturing: Concentration monitoring of caustic soda (NaOH), sodium silicate, and surfactant solutions during blending and quality release.
• Automotive & Industrial Fluids: Glycol content verification in engine coolants and brake fluids per SAE J1087 and ASTM D3372.
• Pharmaceuticals: Excipient concentration checks (e.g., mannitol, dextrose) in liquid dosage forms and lyophilization cycle support.
• Academic Research: Solvent mixture characterization, polymer solution thermodynamics, and phase behavior studies requiring high-resolution n_D tracking.

FAQ

Does the RX-7000i include built-in temperature control?
No. The RX-7000i does not feature active Peltier temperature regulation. It relies on high-accuracy ambient temperature sensing (±0.1 °C) and ISO 21748–compliant algorithmic compensation to maintain measurement validity across −10 °C to +55 °C ambient conditions.
Can I calibrate the instrument for non-sucrose analytes?
Yes. Using the user-defined scale function, up to 10 custom calibration curves can be stored—each defined by ≥5 concentration–n_D reference points. Calibration data may be imported via CSV or entered manually.
Is the prism surface resistant to abrasion and chemical exposure?
The measuring prism is fabricated from synthetic sapphire (Mohs hardness 9), offering exceptional resistance to scratching and compatibility with most common laboratory solvents, including acetone, isopropanol, and diluted acids/bases.
What regulatory standards does the RX-7000i support for validation?
Instrument performance verification follows JIS K 0061 procedures. Measurement uncertainty estimation complies with ISO 21748. Data integrity workflows are compatible with FDA 21 CFR Part 11 when paired with validated software and access controls.
How often does the unit require recalibration?
ATAGO recommends annual factory recalibration or in-house verification using certified sucrose reference standards (e.g., 10.00%, 30.00%, 60.00% w/w) traceable to NIST SRM 84d. Daily verification with distilled water (n_D = 1.3330 at 20 °C) is advised prior to critical measurements.