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70 Years of Automated Titration

There’s evidence of titrations being carried out as far back as the late 18th century. The technique was named in the first half of the 19th century by French chemist Joseph Louis Gay-Lussac, who is often considered to have invented titration. Today, titration is one of the most important analytical techniques. Some reasons for this are that it’s versatile, fast, low in cost, and that it can be easily automated. Automated titration came up in the mid-20th century and Metrohm was one of the pioneers in this field. Metrohm did its first step toward automated titrations when it launched the Titriskop in 1949. This was a pH meter that was specially designed for the needs of people performing titrations. Read here how titration has developed since then.

A First Step Towards Automation

Every chemistry student, and probably almost every science student, has once performed a manual titration with a glass buret. It still makes sense for students to do this to help them understand the principles of titration. However, when the goal of the analysis is getting an accurate and reproducible result within short time, then automation is necessary. The best results are achieved when the titration itself and the sample handling are automated.

COLLECTIE_TROPENMUSEUM_Bedrijfsmedewerker_bezig_met_titreren_TMnr_10007258 (1)

Manual titration at the Museum of the Tropics in Amsterdam, Netherlands, in 1936. Tropenmuseum, part of the National Museum of World Cultures, licensed under CC BY-SA 3.0

 

Automated Dosing and Recording

Metrohm introduced the Titriskop, a pH meter that was specially designed for titrations, in 1949. It enabled analysts to get more precise results by allowing an enhanced resolution in the pH range where the quivalence point was expected. At that time, the titration curve, i.e., pH vs. titrant volume, still had to be drawn manually.

Metrohm replaced the glass buret with the first piston buret in 1957. This improved handling and precision of the titrant addition. [4] In 1961 followed another milestone: the first titrator that recorded the titration curve automatically—the Potentiograph. The image on the right shows a curve drawn by the Potentiograph.

In 1971, titration curves could not only be recorded automatically, but also evaluated thanks to thanks to computer coupling with the Titroprint 475. By integrating microprocessors, the titrators themselves gained computing power. This was the beginning of high-performance titrimetry. [9] The Titroprocessor 636, introduced in 1978, combined microprocessor technology with dynamic titrant addition. This means that smaller addition volumes are used close to the equivalence point in order to keep analysis times short while enhancing precision.

Potentiograph336_Application_lab_Herisau_1959

An employee of the application lab at Metrohm in Herisau measures with the Potentiograph.

Titration Conquers Process Analysis

In parallel to the technological development, titrators were adapted to the locations where they were used. The progressing industrialization after World War II meant that titrators needed a robust housing to withstand the rough process environment. In 1961, Metrohm installed the first Robot-Titrator at Bayer AG in Leverkusen, Germany. The instrument was then continuously developed into the Multi-Titrator 440 (1966). Later, microprocessor technology was also integrated into process titrators.

Software Innovations

Progress in digital electronics allows integrating the whole titrator into the buret. This is the basis for the extremely compact Titrino, which is first launched in 1990. With the TiNet software, this titrator could be controlled remotely from any PC.

The requirements towards both titration software and hardware grew with the documentation requirements in quality control. This was the case especially in the pharmaceutical industry. The demand for flexible sample automation and for electronic records according to FDA 21 CFR Part 11 called for new hardware and software concepts in titration. With the Titrando (2002) and the tiamo software (2004), Metrohm provided the solution to these problems. This successful concept was also translated to atline and online titration where it was completed with the ProcessLab Manager software.

The OMNIS Era

In 2016, Metrohm introduced a new automation concept that increases throughput and allows non-stop operation. Thanks to this, the new titration platform OMNIS can handle large sample amounts. In terms of software, user-friendliness is the buzzword of the moment. This means that software is adapted to the way the user thinks. For example, when several analytes are titrated within the same sample, OMNIS links the results to the sample, rather than to the method used.

In the course of the next few years, other analysis techniques will be added to OMNIS so that it will be able to answer the user’s questions about a sample irrespective of the required technique.

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The new OMNIS platform employs a new automation concept that was developed for the requirements of modern labs handling large sample numbers.

The Most Important Innovations

These were the most important innovations in each field that led to titration how we know it today:

  • Electrode technology: The wide range of electrodes, for example, the Titrode and Surfactant Electrodes, allow for a wide range of samples and analytes.
  • Indication: The variety of sensors available today, for example, the Optrode or the Thermistor, make variable titration methods possible.
  • Dosing technology: Accurate dosing, for example, using the Dosimat 665 or the Dosino 800, is one of the cornerstones of titration.
  • Automation: The possibility to automate titration is one of the main factors that made the technique so popular. The development of sample processors like the Robot Sample Processor 815
  • Sample preparation: The development and automation of sample preparation techniques for titration has made titration suitable for a wide range of samples. One example is Karl Fischer water determination following extraction from the sample as a liquid or gas.
  • Data Processing: Automation in data processing, for example, import of LIMS work lists and export of ERP-compatible reports, has made titration increasingly user-friendly.

Through these innovations, titration has become the accurate, reliable, fast, and easy-to-use technique that it is today.

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2 Comments

  • Dominik Zehnder

    Dear Stephanie & MarCom team

    A great idea! I am looking forward to read your stories with the Metrohm family from around the world!

    Thank you for sharing and hope to meet you either at MHQ or at Metrohm Research Slovakia during your travels!

    Have a safe journey!
    Dominik

    January 8, 2018 - 8:00 pm Reply
  • Stephanie Kappes

    Dear Dominik,

    Thanks so much! I’m sure we’ll meet in the course of the year.

    See you soon!
    Stephanie

    January 8, 2018 - 9:15 pm Reply

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