A.KRÜSS DR301-95 Digital Handheld Refractometer
| Brand | A.KRÜSS / A.KRÜSS Optronic |
|---|---|
| Origin | Germany |
| Model | DR301-95 |
| Sample Measurement Range | 1.3330–1.5318 nD |
| Measurement Accuracy | ±0.00015 nD |
| Temperature Range | 5–40 °C |
| Temperature Accuracy | ±0.5 °C |
| Resolution | 0.0001 nD |
| Display | Digital LCD |
| Power Supply | 9 V battery (detachable AC adapter optional) |
| Prism Material | Optical glass |
| Housing Material | Stainless steel sample stage + polymer body |
| Dimensions | 180 × 100 × 60 mm |
| Weight | 500 g |
Overview
The A.KRÜSS DR301-95 Digital Handheld Refractometer is a precision optical instrument engineered for rapid, field-deployable measurement of refractive index (nD) across liquid and semi-liquid samples. Based on the principle of total internal reflection at the prism-sample interface, the device determines nD by detecting the critical angle of light transition—calibrated against traceable standards traceable to NIST and PTB reference materials. Unlike analog Abbe-type instruments, the DR301-95 employs a high-stability LED light source and a linear CCD photodetector array to digitize the shadow line position with sub-pixel resolution, enabling reproducible measurements under variable ambient lighting. Its design targets laboratories and production environments requiring ISO/IEC 17025-compliant routine analysis without benchtop infrastructure—particularly where portability, ease of cleaning, and multi-parameter flexibility are essential.
Key Features
- Precision optical glass prism with flat-bottom stainless steel sample stage for uniform film formation and rapid residue removal
- Digital LCD display with 0.0001 nD resolution and real-time temperature readout (5–40 °C)
- Factory-calibrated using distilled water (nD = 1.3330 at 20 °C); user recalibration supported via two-point verification
- Programmable temperature compensation (ATC) across 5–40 °C range, compliant with ASTM D1218 and ISO 21748 guidelines
- Two user-definable calibration curves—enabling custom concentration-to-nD conversion for proprietary formulations or non-standard solutes
- Integrated audible and visual alarm system for out-of-range readings or low-battery status
- USB interface (via optional cable) for direct data export to Windows-based software; compatible with CSV and Excel formats
- Robust polymer housing with IP54-rated ingress protection against dust and incidental splashes
Sample Compatibility & Compliance
The DR301-95 accommodates aqueous solutions, syrups, glycols, coolants, brines, alcohol-water mixtures, and low-viscosity organic solvents (e.g., acetone, ethanol, ethylene glycol). It is not intended for strongly corrosive media (e.g., concentrated acids/bases), volatile solvents below 10 °C flash point, or suspensions containing >0.5 µm particulates. Sample volume requirement is ≤0.5 mL. The instrument meets CE marking requirements per Directive 2014/30/EU (EMC) and 2014/35/EU (LVD), and its optical path design conforms to DIN EN ISO 1042 for volumetric accuracy in calibration procedures. For regulated industries, audit trails generated during PC-connected operation support GLP/GMP documentation workflows under FDA 21 CFR Part 11 when used with validated software.
Software & Data Management
When connected to a host PC via USB, the DR301-95 interfaces with KRÜSS RefraSoft™ (v3.2+), a Windows-native application supporting automated batch logging, statistical process control (SPC) charting, and report generation per ISO 9001 Annex A. Data fields include timestamp, operator ID, sample ID, nD, temperature, ATC status, and calibration history. Export functions comply with LIMS integration protocols (ASTM E1482, HL7 v2.5.1). All measurement records retain embedded metadata required for traceability in pharmaceutical QC (USP ) and food safety audits (HACCP, BRCGS).
Applications
- Paper & Pulp: Monitoring coating solution solids content and starch binder concentration
- Beverage & Food: Quantifying sugar (Brix), salt (NaCl %), and acid concentration in juices, sauces, and dairy products
- Pharmaceuticals: Verifying excipient concentration in syrup bases and ophthalmic solutions per USP
- Chemical & Petrochemical: Assessing glycol concentration in heat transfer fluids and antifreeze blends
- Metalworking: Controlling coolant concentration in machining emulsions to prevent microbial growth and corrosion
- Wastewater Treatment: Rapid estimation of dissolved solids and organic load in influent streams
FAQ
Does the DR301-95 support automatic temperature compensation (ATC)?
Yes—ATC is enabled across 5–40 °C using an integrated thermistor; compensation follows the Lorentz-Lorenz equation as implemented in ISO 21748 Annex B.
Can I connect the instrument to a laboratory information management system (LIMS)?
Direct LIMS integration requires RefraSoft™ configured with ODBC drivers and mapping templates; validation documentation is available upon request.
What maintenance is required for long-term accuracy?
Daily prism cleaning with lens tissue and reagent-grade isopropanol; annual verification against certified nD standards (e.g., Cargille Labs Series AA) is recommended.
Is the device suitable for use in hazardous areas?
No—the DR301-95 lacks ATEX or IECEx certification and must not be operated in classified zones per NEC Article 500.
How is traceability ensured for calibration?
Each unit ships with a factory calibration certificate referencing PTB-traceable refractive index standards, including uncertainty budgets per GUM (JCGM 100:2008).
