Comprehensive Analysis and Repair Guide for Potentiometric Titration Systems

I. Overview of Potentiometric Titration System

The potentiometric titration system is a widely used analytical instrument in fields such as chemistry, environmental protection, food, and pharmaceuticals. It observes and measures changes in the potential of a solution under test to determine the endpoint of titration analysis and perform quantitative analysis. The system consists of an indicator electrode and a reference electrode, forming a working cell that monitors potential changes during the titration process to accurately calculate the content of the component being tested.

II. Principle of Potentiometric Titration System

The basic principle of the potentiometric titration system is based on electrochemistry. In the titration solution, an indicator electrode and a reference electrode are inserted to form a working cell. As the titrant is gradually added, a chemical reaction occurs between the tested ions and the titrant, leading to changes in ion concentration and, consequently, corresponding changes in the potential of the indicator electrode. When approaching the stoichiometric point, significant changes in the concentration of the tested ions in the solution occur, resulting in a sudden jump in the potential of the indicator electrode. By observing and measuring changes in the electromotive force of the working cell, the endpoint of titration can be determined, and the content of the tested component can be calculated accordingly.

III. Usage Method of Potentiometric Titration System

Preparation:

• Select appropriate indicator and reference electrodes based on the type of titration reaction.
• Install the electrodes, ensuring correct connection of positive and negative terminals.
• Install the burette and solenoid valve, connect relevant tubing, and fill with titration solution.

Parameter Setting:

• Select the preset endpoint potential value and adjust the potentiometer to the required value.
• Select the mv or pH range as needed and fix the preset potentiometer.

Titration Operation:

• Start the titration, controlling the titration speed to avoid being too fast or too slow.
• Observe potential changes. When approaching the endpoint, the potentiometer will automatically adjust the titration speed (e.g., approximately 0.02 ml each time) until reaching the endpoint potential.
• The endpoint indicator light will illuminate, and a buzzer will sound, indicating the end of the titration.

Data Processing:

• Record the volume of titrant consumed at the endpoint and calculate the content of the tested component using the formula.

IV. Common Faults and Repair Methods of Potentiometric Titration System

Inaccurate Reading:

• Cause: Electrode contamination or expired indicator solution.
• Repair Method: Clean the electrode surface to remove contamination; replace expired indicator solution.

Unstable Measurement:

• Cause: Bubbles in the sample or incomplete immersion of the electrode.
• Repair Method: Stir the sample to eliminate bubbles; adjust the electrode position and angle to ensure complete immersion in the sample.

Non-Responsive Electrode:

• Cause: Electrode distortion or contamination.
• Repair Method: Inspect the electrode appearance and replace if distorted; clean the electrode surface to remove contaminants.

Low Titration Liquid Level:

• Cause: Insufficient injection or volume of titration liquid.
• Repair Method: Fully inject the titration liquid; adjust the volume of titration liquid to ensure sufficiency.

Large Reading Fluctuation:

• Cause: Electrode residue, expired or contaminated reagents, or loosely closed reagent bottle caps.
• Repair Method: Clean and calibrate the electrode; check and replace expired or contaminated reagents; ensure tight closure of reagent bottle caps.

Leakage Issues:

• Cause: Damaged liquid level sensor, open or clogged drip control valve.
• Repair Method: Replace the liquid level sensor; check and close the drip control valve; clean the drip tubing.

Abnormal Display or Non-Function:

• Cause: Power connection issues, damaged display screen.
• Repair Method: Check power connections and supply; replace the damaged display screen.

Other Faults:

For complex issues such as internal circuit faults, sensor faults, and control board faults, it is recommended to contact professionals for repair.

V. Summary of Repaired Potentiometric Titration System Brands and Models by Longi Electromechanical

1. Metrohm
   • Titrando Series: 888 Titrando, 890 Titrando, 905 Titrando, 906 Titrando
   • Eco Titrator: Basic Titration System
   • Ti-Touch Series: 916 Ti-Touch, 915 KF Ti-Touch
2. Mettler Toledo
   • T70 Series: T70 Excellence, T90 Excellence
   • Compact Series: G20 Compact, G10 Compact, G30 Compact
   • InMotion Series: InMotion Flex, InMotion Max
   • EasyPlus Series: EasyPlus Titrator
3. Kyoto Electronics Manufacturing (KEM)
   • AT Series: AT-710, AT-510
   • MKC Series: MKC-710, MKC-610
4. Hanna Instruments
   • HI902C: Automatic Potentiometric Titrator
   • HI931: Automatic Potentiometric Titrator
5. Hach
   • Titralab AT1000 Series: AT1102, AT1112, AT1122
6. Titrando
   • T70: Universal Potentiometric Titration System
   • T90: Advanced Potentiometric Titration System
7. Analytik Jena
   • Titration Excellence Series: TL 7000, TL 7750, TL 7800
8. SI Analytics (Xylem)
   • TitroLine Series: TitroLine 5000, TitroLine 7000, TitroLine 7750
9. Hiranuma
   • COM Series: COM-300A, COM-1700
10. KNAUER
    • Smartline: Fully Automatic Potentiometric Titration System
11. Thermo Fisher Scientific
    • Orion Star T900: Potentiometric Titration System
12. Bante Instruments
    • Bante900: Automatic Potentiometric Titrator

Longi Electromechanical has nearly 30 years of experience in repairing potentiometric titration systems and can quickly repair various instruments. Additionally, we recycle and sell various potentiometric titration systems. Welcome to consult.