Abbe Refractometer
Abbe Refractometer with Temperature-Controlled Prisms
Ocular Abbe Refractometer
Expert Abbe Refractive Index Analysis
ASTM D1648

Professional Analog LED Refractometer QPI‑AR2800 - Application:

ASTM Test Method (Optical Refractive Index Measurement)

The QPI‑AR2800 Analog LED Refractometer follows the optical measurement principles referenced in ASTM E1331, ASTM D1218, and related refractive index standards used for transparent liquids and solids. This method defines how refractive index is determined using a precision optical system with controlled illumination and temperature stabilization.

Procedure Summary

1. Instrument Preparation

   • Clean the prism surfaces with lint‑free tissue and solvent.

   • Verify LED illumination uniformity and temperature stability (typically 20 °C ± 0.5 °C).

   • Calibrate using a certified reference liquid with known refractive index.

2. Sample Application

   • Place a small droplet of the test liquid on the measuring prism.

   • Close the prism cover to ensure full optical contact and eliminate air bubbles.

3. Measurement

   • Observe the boundary line through the eyepiece under LED illumination.

   • Adjust the fine focus knob until the light/dark interface is sharp.

   • Read the refractive index directly from the analog scale.

4. Temperature Compensation

   • Record the prism temperature using the integrated LED temperature indicator.

   • Apply ASTM correction factors if the sample deviates from the reference temperature.

5. Reporting

   • Report refractive index (nD) at the measured temperature.

   • Include calibration fluid, sample type, and environmental conditions.

Engineering Purpose

This ASTM‑aligned procedure ensures repeatable optical precision for evaluating:

• purity and concentration of transparent liquids

• resin and polymer formulations

• coating and adhesive materials

• sugar and solvent mixtures

It is widely used in chemical, food, and materials laboratories for quality control and formulation verification.

ISO Test Method (ISO Optical Measurement Practice)

The ISO‑aligned procedure corresponds to ISO 15212‑1 and ISO 5661, which define refractometric measurement using Abbe‑type instruments under controlled laboratory conditions.

Procedure Summary

1. Calibration and Setup

   • Verify prism cleanliness and LED brightness uniformity.

   • Calibrate using ISO‑traceable reference liquids.

2. Sample Loading

   • Apply the sample evenly across the prism surface.

   • Ensure no trapped air or particulate contamination.

3. Optical Reading

   • Adjust the focus until the boundary line is crisp.

   • Record the refractive index and temperature simultaneously.

4. Repeatability Check

   • Perform at least three readings per sample.

   • Confirm deviation within ISO tolerance limits (typically ±0.0002 nD).

5. Documentation

   • Record refractive index, temperature, calibration fluid, and operator initials.

   • Maintain traceability per ISO laboratory documentation standards.

Engineering Purpose

The ISO method emphasizes traceable precision and international comparability, making it ideal for:

• pharmaceutical and cosmetic formulations

• optical resin and polymer testing

• food and beverage quality assurance

• academic and industrial research laboratories