Titrimetric Citric Acid Determination at Coca-Cola Services Belgium

Coca-Cola is the world’s leading producer of non alcoholic beverages, which are manufactured in approximately 1000 production plants. In addition to bottling plants, the company has a number of technical centers spread across the globe, where quality assurance (QA) is managed, and new packages and products are developed.

Coca-Cola executes many QA-activities, and among these one is dedicated to establishing the quality aspects of products that are bought from the local markets. Such quality attributes are examined to confirm whether the products conform to the internal specifications and meets the customers and consumers’ expectations. All of these activities are performed in European Quality Centers (EQC).

For over a decade, Coca-Cola has continued to be associated with Metrohm. Earlier in 2004, Coca-Cola visited the Mexican subsidiary and presented a new Metrohm titration system to the Belgian people. After listening to the excellent experiences of the Mexican associates, the company decided to establish a closer cooperation with Metrohm Belgium.

Requirements for a New System

Citric acid concentration and pH value in various beverages are the parameters that need to be measured by the new system. As large amounts of products have to be examined, there was extremely high workload in the laboratory of Coca-Cola Services (the company’s Belgian subsidiary). It is of major significance that an ideal analysis system should provide precise and consistent results, and at the same time should have a high throughput and the required ability to operate many samples without any operator intervention overnight.

Different types of samples have to be handled without having to physically adapt the workstation all the time. Given that sample preparation (pipetting) of this bulk amount of samples takes a considerable amount of time and is also more prone to errors, Coca-Cola Services welcomed the concept of an automated system that provides a professional and reproducible sample preparation from the outset.

The Fully Automated Titration System

The titration system is fully automated and includes two 814 USB sample processors fitted with two external titration vessels, two 800 Dosinos with Dosing Units, two 772 Pump Units, an 808 Titrando with two measurement inputs, an 802 Stirrer (propeller stirrer), an 805 Dosimat, and an 804 Ti Stand (Figure 1). Sample racks are fitted to both set-ups, and these racks are capable of handling up to 127 vials with a volume of 11 mL sample each. A pipetting tube, controlled by Dosino and equipped with a uniquely-designed needle, is used to transfer the sample. This needle can also manage sample containing pulp (Figure 2).

Figure 1. Julie Tilquin is the responsible lab technician for the fully automated Metrohm titration system.

Figure 2. Close-up of the specially-designed needle for the aspiration of even pulpy samples.

The Determination

The determination is automatically performed. Therefore, following the degassing process, the beverage samples are placed on the sample rack and the sample data table is filled with the suitable sample data. These are the only manual tasks involved.

10 mL of the sample is automatically pipetted into the external titration cell, where some additions of auxiliary solutions are added. Following electrode calibration, the citric acid titration is carried out. Pipetting, cleaning, quantifying, and titrating of the system are automatically carried out in a single run.

Data Evaluation

Metrohm‘s tiamo™ is a proven titration software that is used to fully control the titration system. With the aid of the tiamo™ multi version, it is possible to check the outcomes of varied workplaces from any office desk through the well-organized and intuitive user interface. The database offers the required tools for controlling results, looking for them, and assembling them jointly.

Quick filters enable a quick search via a countless number of determinations. In addition, control charts give a quick overview of the chronological order of the outcomes. The tiamo™ software conforms to the requirements of FDA Regulation 21 CFR Part 11.

Conclusion

Since February 2005, the European Quality Centre in Brussels has been using the Metrohm system and is quite happy with the results, because all its demands are fully met.

  • Fast and time-saving analysis
  • High throughput
  • Excellent precision and reproducibility
  • Dependable system that offers unattended operation overnight
  • Quick and competent support by Metrohm, if required

Metrohm’s fully automated, customized system can be effectively used to prepare and analyze large amounts of beverage samples. The samples’ citric acid concentration can be easily tracked from the office desk.

This information has been sourced, reviewed and adapted from materials provided by Metrohm AG.

For more information on this source, please visit Metrohm AG.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Submit