Automatic Potentiometric Titrator

What is the Automatic Potentiometric Titrator?

An automatic potentiometric titrator dispenses titrant with a motorized burette and detects the endpoint by electrode potential. It is the general-purpose choice for acid-base, redox, argentometric and complexometric titrations in QC and research laboratories needing reproducible, documented results.

Overview

This variant combines a motor-driven piston burette, typically 10 or 20 mL, with a high-impedance potential measurement input for pH, ion-selective, redox or silver electrodes. The controller evaluates the titration curve and locates equivalence points automatically, supporting multiple endpoints in a single run. Methods are stored and recalled, results are calculated with user-defined formulas and exported to a LIMS or printer. Dynamic equivalence-point titration adjusts dose size to the curve slope, shortening run time without sacrificing accuracy. It is suited to laboratories running a variety of titrations rather than one dedicated parameter, and it can be upgraded with a sample changer or additional burettes. It is not the preferred platform for trace-water determination, which requires a sealed Karl Fischer cell.

How does it work?

A titrator combines a precision burette or coulometric generator electrode, a stirred titration vessel, a sensor and a control unit. In volumetric titration, a motor-driven piston burette dispenses titrant while a sensor, usually a pH glass electrode, redox platinum electrode or photometric probe, tracks the solution. The endpoint is identified as a preset potential or the inflection point of the titration curve, and the result is calculated from titrant volume, concentration and stoichiometry. In coulometric Karl Fischer titration, iodine is generated electrochemically at a generator electrode and the charge passed, according to Faraday's law, gives the mass of water directly without a burette. Dynamic dosing slows addition near the endpoint to improve accuracy, and automatic sample changers allow unattended series.

What are the key features?

• Motorized piston burette with 10,000-step or finer resolution for accurate dosing
• Dynamic and monotonic dosing modes that adapt dose size to curve slope
• Multiple endpoint and equivalence-point evaluation in a single titration run
• Stored methods with user-defined calculations and LIMS-compatible result export
• Expandable with sample changer, additional burettes and stirrer modules
• Electrode recognition and calibration records for pH and ion-selective sensors

What are the technical specifications?

A typical automatic potentiometric titrator configuration offers burette volume of 10 mL or 20 mL (exchangeable), dosing resolution of 1/20,000 of burette volume (0.5–1 µL), dosing accuracy of ±0.15% of burette volume, potential measuring range of ±2000 mV, potential resolution of 0.1 mV and pH measuring range of −2 to 20 pH. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Automatic Potentiometric Titrator is used in acid number and base number of oils, chloride by silver nitrate titration, alkalinity and acidity of water, redox titration of vitamin C or iron and assay of active ingredients by nonaqueous titration. Across the wider Titrators class, laboratories also deploy it for water determination in oils and solvents, acid and base number of petroleum products and chloride and salt content in food and water.

Which standards and certifications apply?

Relevant standards and methods include ASTM D664, ASTM D974, ASTM D6304, ASTM E203, ISO 760, USP <921> and IEC 61010-1. Certification candidates for this model are CE, ISO 9001 manufacturing and RoHS; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Place the titrator on a vibration-free bench away from drafts and direct sunlight. Standardize titrants regularly against a primary standard such as potassium hydrogen phthalate or sodium oxalate, and record the titer. Verify electrodes with buffers and check the burette volume gravimetrically at defined intervals. For Karl Fischer work, replace desiccant, keep the cell sealed, check drift before each series and verify with a certified water standard. Rinse tubing when changing titrants to avoid cross-contamination, and inspect piston seals and valves as part of preventive maintenance. Dispose of reagents, particularly pyridine-free Karl Fischer solutions and organic solvents, according to local waste rules.

How do I select the right Automatic Potentiometric Titrator?

Select this variant when the laboratory runs several titration chemistries and needs flexibility and documented evaluation of the titration curve. Choose a sibling Karl Fischer model for water determination. In an RFQ, specify burette volume, number of burettes, required sensors, sample changer positions, applicable standards such as ASTM D664, and software features like audit trail and LIMS export.

How does it compare with other Titrators variants?

The decisive choice is the titration chemistry. Water in oils, solvents and solids calls for Karl Fischer, volumetric above about 0.1% water and coulometric below it. Acid and base number in petroleum products and general acid-base, redox, argentometric and complexometric titrations call for a potentiometric titrator. Consider sample throughput, because an automatic sample changer is justified beyond roughly 20 samples per day. Check burette resolution, available sensors and whether the software supports the standard methods you run, such as ASTM D664 or ASTM D6304. Also weigh solvent consumption and waste handling, reagent storage for moisture-sensitive titrants, and whether audit-trail and user management features are required for accredited or regulated work.