Karl Fischer titration is a standard technique for the determination of water content in a variety of samples. Although valuable in R&D, quality control, and production monitoring, challenges of the Karl Fischer (KF) method include requirements for high quality sample preparation in order to release trapped, capillary-bound, or crystallized water. In response, technology development has focused on temperature and gas flow assisted water extraction from samples, upstream and in-line with KF titration equipment.

METTLER TOLEDO has significantly refined this KF oven technology and has accelerated the KF titration workflow through advanced autosampling capabilities. The latest state-of-the-art technology - the InMotion KF Oven AutoSamplers – have been designed with intelligence in mind to bring precise and efficient Karl Fischer titrations to every laboratory.

Many substances have qualities which make accurate direct analysis by the KF titration apparatus challenging. For instance, plastics may only release water slowly or at high temperatures. Other samples may require special solvents and preparation steps that are incompatible with KF reagents. Still others such as inorganic salts may undergo side-reactions with KF reagents leading to imprecise results. For these reasons, the KF oven method was developed to provide the necessary sample preparation conditions without contaminating and compromising the KF titration equipment.

A prototypical KF oven apparatus heats the sample to a designated temperature and uses a carrier gas to transfer the released water to the titration device. Key performance metrics of these devices include: precise weighing and sample treatment methods for increased reproducibility, and automated sample prep and delivery to minimize variability and maximize efficiency.

Released in 2008, the Stromboli oven sample changer from METTLER TOLEDO was an advanced design that combined gas drying and temperature control in an easy to use platform. The new InMotion KF Oven AutoSamplers dramatically improve upon this design, offering a host of significant advancements and a compelling case for upgrading to this latest technology.

The InMotion KF integrates an automatic gas flow meter which gives the operator complete control of gas entering and exiting the titration cell. An improved one-piece screw cap ensures sample preparation and delivery is quick, safe, and precise.

A top priority for busy and productive labs is efficiency in terms of workflow and throughput. Temperature Scan is an innovative feature of the InMotion KF Pro that determines the substance’s ideal temperature in order to maximize the yield and speed of analysis. The InMotion KF can run up to 120 samples in one series without stopping, improving both the workflow and ease of use. In addition, the InMotion KF has a sleek profile and ergonomic design lending to efficient use of precious lab space.

The InMotion KF allows up to 26 samples to be processed on a 25-cm rack. The KF Pro offers three vial sample protocols to choose from, to address the needs of a broad range of labs and applications. Beyond these features, the InMotion KF enables custom design of methods to suit the needs of specialized or dynamic labs.

The InMotion KF is fully compliant with current OMCL guidelines through calibration of oven temperature and gas flow rate to the titrator cell. The devices are supplied with complete documentation and are backed up with service and support throughout their entire lifetime – the same standard of service METTLER TOLEDO provides for all titration instruments.

Advanced User Control
The InMotion KF utilizes additional options to maximize resources in the lab. The ability to connect up to two InMotion KF devices at a time to the Titration Excellence T7 or T9 saves time, space, and money. Use of the Solvent Manager extends the life and improves consistency by providing flexible automation and user control.

Prominent status lights indicate whether the analysis is running, complete, or requires attention. The LabX™ software emails results to the user, further streamlining operations and workflow. This software also anticipates the varying demands of users, offering flexibility and simplified use in addition to custom reporting.

All methods are stored in a central database and method protocols can be queued to work with defined sample sets. The LabX™ software has a regulation option as well, providing all the necessary tools to meet FDA regulation 21 CFR Part 11 for data management and storage. The InMotion KF Pro enables customized method development and the option of unattended solvent exchange as well – further freeing up time and resource in the lab.

All of these state-of-the-art features together represent sizable improvements over previous technologies. The seamless integration of the InMotion KF Oven AutoSampler with downstream KF titration instruments ensures fast, efficient, and reliable operation. The ability to control all of the parameters and options from a central interface puts power firmly in the hands of the operator - as it belongs.

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This article was written by LabX and published in conjunction with Mettler Toledo

METTLER TOLEDO is a global manufacturer and marketer of precision instruments for use in laboratory, industrial and food retailing applications. The Company has strong worldwide leadership positions. A significant majority of our instrument sales are in segments in which we are the global leader. In addition to a broad product offering, we have one of the largest global sales and service organizations among precision instrument companies.

We focus on the high value-added segments of our markets by providing innovative instruments that often integrate various technologies including application-specific solutions for customers. We design our instruments not only to gather valuable data but also to facilitate the processing and transfer of this data into customers' management information systems.