ATAGO MASTER-Pα Handheld Refractometer
| Brand | ATAGO |
|---|---|
| Origin | Japan |
| Model | 2391 |
| Product Type | Handheld Refractometer |
| Temperature Compensation | Automatic (ATC) |
| Measurement Range | 0.0–33.0% Brix |
| Minimum Scale Division | 0.2% Brix |
| Accuracy | ±0.2% Brix (at 10–30°C) |
| Repeatability | ±0.1% Brix |
| Dimensions | 3.3 × 3.3 × 20.4 cm |
| Weight | 100 g |
| IP Rating | IP65 (excluding eyepiece area) |
| Accessories | RE-29401 Extractor, RE-110010 (10% sucrose standard, ±0.03%), RE-110030 (30% sucrose standard, ±0.03%), RE-2311-55M micro-sample prism cover, RE-2311-54M daylight plate |
Overview
The ATAGO MASTER-Pα Handheld Refractometer (Model 2391) is a precision optical instrument engineered for rapid, field-deployable Brix concentration measurement in liquid and semi-liquid samples. Based on the principle of critical angle refraction, it determines soluble solids content by measuring the refractive index of a sample placed on its sapphire-coated prism surface. Unlike benchtop digital units, the MASTER-Pα employs an analog optical scale with high-contrast etched glass reticle, eliminating reliance on batteries or electronic displays while maintaining metrological integrity under ambient laboratory, production line, or outdoor conditions. Its built-in Automatic Temperature Compensation (ATC) mechanism—calibrated to the standard sucrose/water system—ensures consistent Brix readings across a 10–30°C operational range without manual correction. Designed for durability and environmental resilience, the unit meets IP65 ingress protection standards (excluding the eyepiece), rendering it resistant to dust ingress and low-pressure water jets—making it suitable for use in food processing facilities, agricultural grading stations, beverage QC labs, and horticultural field testing where robustness and portability are essential.
Key Features
- Optical Brix scale with 0.2% Brix minimum division and parallax-free viewing through precision-ground eyepiece
- Automatic Temperature Compensation (ATC) using bimetallic thermal expansion elements, optimized for sucrose solutions per ISO 2173:2003
- Sapphire-coated measurement prism for scratch resistance and long-term optical stability
- Compact, lightweight design (100 g) with ergonomic form factor enabling one-handed operation
- IP65-rated housing (excluding eyepiece) certified to IEC 60529, ensuring reliable performance in humid, dusty, or washdown-prone environments
- No battery or power source required—fully mechanical optical system ensures zero downtime and infinite operational lifespan
Sample Compatibility & Compliance
The MASTER-Pα is validated for aqueous solutions where refractive index correlates linearly with sucrose concentration—including fruit juices, syrups, soft drinks, honey, maple sap, and certain dairy-based liquids. It is not intended for highly viscous, opaque, or suspended-particle-laden samples unless pre-filtered or diluted to optical clarity. For trace-volume applications, the optional RE-2311-55M micro-prism cover reduces required sample volume to ~0.3 mL. Calibration verification is supported via traceable NIST-traceable sucrose reference standards (RE-110010 and RE-110030, each certified to ±0.03% Brix). The instrument complies with ISO 2173 (fruit and vegetable products), AOAC Official Method 932.12 (Brix determination), and supports GLP documentation requirements when used with standardized SOPs and logbook entries.
Software & Data Management
As a purely optical, non-digital instrument, the MASTER-Pα does not interface with software or generate electronic data outputs. All measurements are manually recorded, supporting audit-ready paper-based workflows compliant with FDA 21 CFR Part 11 Annex 11 (where electronic systems are not deployed). Users may integrate readings into LIMS or ELN platforms via manual entry, with full traceability ensured through concurrent recording of operator ID, time/date stamp, calibration standard lot number, and environmental temperature. Optional accessories—including the RE-29401 sample extractor—facilitate consistent droplet application and minimize operator-induced variability, thereby enhancing inter-operator reproducibility in regulated environments.
Applications
- Routine Brix screening of raw fruits and vegetables during harvest and post-harvest sorting
- In-line quality control of juice concentrates, jams, and confectionery syrups in food manufacturing
- Field-based assessment of sugar content in sugarcane, sugar beet, and maple sap prior to processing
- QC verification of incoming raw materials such as invert sugar, glucose syrup, and malt extract
- Educational use in chemistry and food science laboratories for teaching refractive index principles and solution thermodynamics
- Validation support for HACCP and ISO 22000 food safety management systems through documented Brix trending
FAQ
Does the MASTER-Pα require battery power or charging?
No. It operates entirely optically and contains no electronic components.
Can it measure non-sucrose solutions like sodium chloride or ethylene glycol?
No. Its scale and ATC are calibrated specifically for sucrose-water systems per ISO 2173; alternative solutes require separate calibration curves.
What is the recommended recalibration frequency?
Calibration should be verified before each shift or measurement session using RE-110010 or RE-110030 standards; full recalibration is performed only if deviation exceeds ±0.2% Brix.
Is the prism surface serviceable or replaceable?
Yes. The sapphire-coated prism assembly is a field-replaceable component (part number RE-2311-54M includes daylight plate; prism replacement kits are available under ATAGO service codes).
How does IP65 rating affect cleaning protocols?
The main body may be rinsed with potable water or wiped with damp cloth; avoid submerging or applying high-pressure spray directly to the eyepiece or hinge areas.
