Polarimeter: Detailed Principles, User Guide, and Comprehensive Fault Repair Guide

Polarimeter: Detailed Principles, User Guide, and Comprehensive Fault Repair Guide

I. Overview

The polarimeter is a precision optical instrument primarily used to measure the optical rotation of substances exhibiting chirality. Optical rotation, a measure of how a substance rotates polarized light, enables the analysis and determination of substance concentration, content, and purity. Polarimeters find wide application in pharmaceutical production, drug inspection, sugar manufacturing, food processing, chemical industry, petroleum, as well as in scientific research and education for laboratory analysis and process quality control.

II. Principles

The working principle of the polarimeter is based on the phenomenon of optical rotation exhibited by substances on polarized light. Natural light, after passing through a polarizer, becomes plane-polarized light. When this plane-polarized light passes through a chiral substance, its vibration direction rotates by a certain angle, known as the optical rotation. The polarimeter measures the angle change before and after the polarized light passes through the chiral substance to determine its optical rotation. Specifically, the polarimeter employs a light source that emits light, which, after passing through a color filter and a polarizer, forms plane-polarized light. This light rotates when it passes through a polarimeter tube containing the chiral substance, and is then observed and measured through an analyzer and an eyepiece assembly to obtain the optical rotation value.

III. Usage Instructions

Preparation:

• Place the polarimeter on a stable workbench, connect the power supply, and preheat until the light source stabilizes (usually 5-10 minutes).
• Check if all components of the instrument are intact and the polarimeter tube is clean and free of impurities.

Zero Calibration:

• Turn on the instrument and use a blank solvent (e.g., distilled water) for zero calibration.
• Inject the blank solvent into the polarimeter tube, place it in the sample chamber, adjust the analyzer to the zero position, and ensure uniform field brightness.
• Repeat the operation several times to ensure the instrument’s stability and reliability.

Sample Testing:

• Inject the sample into the polarimeter tube, ensuring no bubbles and that the tube is fully filled.
• Place the tube back in the sample chamber, adjust the analyzer to the appropriate position for optimal field brightness.
• Read and record the displayed optical rotation value.

Repeated Measurements and Averaging:

• For improved accuracy, repeat measurements on the same sample and take the average as the final result.

Completion:

• After testing, turn off the instrument, clean the polarimeter tube and sample chamber, return the instrument to its place, and make usage records.

IV. Faults and Repair Methods

Light Source Faults:

• If the light source does not illuminate or is insufficiently bright, check the power supply, bulb integrity, and optical path clearance.
• Replace the bulb or clean the optical path to resolve the issue.

Unstable Readings:

• Fluctuating readings may result from environmental temperature changes, lack of calibration, or loose mechanical parts.
• Ensure the instrument is used in a constant temperature environment, calibrate regularly, and check the tightness of mechanical parts.

Polarimeter Tube Contamination:

• Contamination of the polarimeter tube’s inner wall affects measurements.
• Regularly clean the inner wall with a dedicated cleaner and soft cloth, avoiding scratches.

Circuit Faults:

• Circuit issues, such as the instrument not turning on or no display, may result from poor power cord connection, blown fuses, or damaged circuit boards.
• Check power cord connections, replace fuses, or contact professional repair personnel for circuit board faults.

Mechanical Part Damage:

• Damaged mechanical parts, such as stiff analyzer rotation or loose eyepiece assemblies, affect measurement accuracy and stability.
• Regularly inspect mechanical parts for damage and replace them promptly to ensure proper instrument operation.

V. Brands and Models of Polarimeters Repaired by Longi Electromechanical

1. Anton Paar
   • MCP Series: MCP 100, MCP 150, MCP 200, MCP 300, MCP 500
2. Rudolph Research Analytical
   • Autopol Series: Autopol I, Autopol II, Autopol III, Autopol IV, Autopol V, Autopol VI
3. JASCO
   • P Series: P-2000, P-1010, P-1020, P-1030, P-2000
4. Schmidt+Haensch
   • Polartronic Series: Polartronic M, Polartronic H532, Polartronic V, Saccharomat
5. Bellingham + Stanley (Xylem)
   • ADP Series: ADP440+, ADP450, ADP600, ADP660
6. Atago
   • POLAX-2L: Automatic Polarimeter
   • DigiPol Series: DigiPol-781, DigiPol-782
7. A.KRÜSS Optronic
   • P Series: P3000, P8000, P8000-TF
8. Thermo Fisher Scientific
   • Orion Series: Orion 420
9. HORIBA Scientific
   • SEPA Series: SEPA-200
10. MRC Lab
    • POL Series: POL-1/2, POL-2/2, POL-3/2
11. Shanghai Insmark Instrument
    • WZZ Series: WZZ-2B, WZZ-3, WZZ-3A
12. PerkinElmer
    • 341 Series: Model 341
13. Rudolph Instruments
    • Autopol Series: Autopol I, Autopol II, Autopol III
14. DigiPol Technologies
    • DigiPol Series: DigiPol-781, DigiPol-782
15. Hahnshin Scientific
    • HP Series: HP-300, HP-500

Longi Electromechanical Company specializes in polarimeter repairs with nearly 30 years of experience, ensuring quick and efficient repairs for various instruments. Additionally, we offer polarimeter recycling and sales. For more information, please contact us.