ATAGO PAL-25s Inulin Concentration Refractometer

Overview

The ATAGO PAL-25s Inulin Concentration Refractometer is a precision handheld optical instrument engineered for rapid, on-site quantification of inulin concentration in aqueous solutions. It operates on the fundamental principle of refractometry—measuring the refractive index (RI) of a sample and converting it to mass concentration (% w/w, g/100g) via a pre-calibrated inulin-specific scale. Unlike generic Brix refractometers, the PAL-25s employs a dedicated optical path and algorithm optimized for inulin’s unique dispersion characteristics in water, ensuring metrological traceability to reference sucrose and inulin standard solutions validated per ISO 2173 and JIS K 0061 protocols. Its compact, ergonomic design integrates a high-stability prism assembly, LED illumination source, and CMOS photodetector array, enabling consistent measurement performance across variable ambient conditions without external power or calibration fluids.

Key Features

• Optimized optical calibration for inulin: Factory-calibrated using certified inulin reference standards (polyfructose, DP ≥ 20), minimizing cross-sensitivity to glucose, fructose, or sucrose commonly present in extraction matrices.
• Automatic Temperature Compensation (ATC): Real-time correction across 10–40 °C using integrated thermistor feedback, eliminating manual correction tables and reducing operator-induced error.
• Digital LCD display with backlight: High-contrast, 4-digit resolution output showing concentration (%) and measured temperature simultaneously.
• Rugged aluminum alloy housing: IP65-rated enclosure resistant to dust, moisture, and incidental chemical splashes encountered in food processing, nutraceutical R&D, and pilot-scale fermentation environments.
• Single-drop measurement capability: Requires only 0.3 mL sample volume; prism surface accommodates viscous inulin syrups up to 500 mPa·s without air bubble entrapment.
• Battery-powered operation: Powered by two AAA alkaline batteries (≥ 10,000 measurements per set), supporting field use in cleanrooms, cold storage areas, or production lines without AC access.

Sample Compatibility & Compliance

The PAL-25s is validated for use with clarified aqueous inulin solutions derived from chicory root, Jerusalem artichoke, or synthetic enzymatic hydrolysates. It supports samples containing ≤ 5% suspended solids and ≤ 2% total dissolved salts without significant RI deviation. Turbid or highly colored samples require centrifugation or filtration (0.45 µm PVDF membrane) prior to analysis. The instrument complies with international refractometric testing standards including ISO 2173 (fruit juices and related products), ASTM D1250 (petroleum measurement tables, adapted for aqueous carbohydrate systems), and JIS K 0061 (general methods for refractive index determination). While not FDA 21 CFR Part 11 compliant as a standalone device, its measurement records may be integrated into LIMS or ELN platforms meeting GLP/GMP audit requirements when paired with timestamped digital logging accessories.

Software & Data Management

The PAL-25s operates as a stand-alone instrument with no embedded data storage or USB connectivity. However, its analog output (0–1 V DC proportional to concentration) enables seamless integration with industrial PLCs, SCADA systems, or third-party data loggers (e.g., Omega OM-DAQPRO-5300) for real-time process monitoring. For laboratory documentation, users may manually record results alongside batch ID, operator name, and environmental temperature in paper-based or electronic lab notebooks adhering to ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate, Complete, Consistent, Enduring, Available). ATAGO provides optional calibration verification kits (Cat. No. 4425-CAL) containing NIST-traceable inulin standards for periodic performance checks per internal SOPs.

Applications

• Quality control of inulin powders and liquid concentrates during manufacturing and packaging.
• In-process monitoring of enzymatic hydrolysis or thermal degradation kinetics in pilot bioreactors.
• Verification of inulin recovery yield after solvent extraction or membrane filtration steps.
• Stability testing of functional food formulations containing inulin as prebiotic fiber.
• Raw material acceptance testing at receiving docks for chicory-derived inulin shipments.
• Academic research on structure-function relationships of inulin chain length distribution (DP profile) via correlation with refractive index trends.

FAQ

Does the PAL-25s require recalibration before each use?
No—factory calibration remains stable for 12 months under normal handling. Daily verification with zero-standard (distilled water) and one-point check using 5.0% inulin reference solution is recommended per ISO/IEC 17025-aligned QC procedures.
Can it measure inulin in fermented broth containing ethanol or organic acids?
Ethanol concentrations >3% v/v or organic acid titratable acidity >0.5% w/w will introduce systematic bias; dilution with deionized water followed by ATC-adjusted reading is required.
Is the prism surface chemically resistant to cleaning agents?
Yes—the sapphire-coated BK7 glass prism withstands repeated cleaning with 70% ethanol, isopropanol, or mild non-ionic detergents; avoid halogenated solvents or abrasive cloths.
How does it differ from a standard Brix refractometer?
Brix scales assume sucrose-equivalent RI behavior; inulin exhibits ~12% lower RI per unit % w/w—using a Brix instrument introduces systematic overestimation. The PAL-25s applies a proprietary inulin-specific conversion curve.
What is the minimum sample temperature equilibration time?
For samples within the ATC range (10–40 °C), stabilization occurs within 3 seconds of prism contact; for samples outside this range, pre-conditioning to ≥10 °C is mandatory to prevent condensation and optical distortion.