Automation in pesticide analysis

The DIN 17025-certified laboratory analyses food and animal feed qualitatively and quantitatively for a total of 800 different pesticides. If a sample is received in the morning, the corresponding analysis result must be available by 4 p.m. at the latest. This is because critical processes depend on the analysis, for example if a container with food is waiting in the harbour or production is at a standstill until the sample has been analysed. Even under great time pressure, the quality of the analysis must remain reliably high.

Fine work in piecework

Until now, laboratory staff have carried out all process steps in pesticide analysis manually. Such monotonous, manual tasks are becoming less popular with each new generation of specialists. In view of the shortage of skilled labour, it can be a competitive advantage for companies if laboratory staff are relieved of repetitive manual work. „Chemical laboratory technicians have learnt pipetting and titration, but in the modern working world it no longer makes sense to carry out these processes manually“, explains Dr Alexander Zahm, Managing Director of Eurofins Dr Specht Express GmbH. „Rather, the professional field is developing in such a way that they apply the knowledge from their training to operate robots accordingly.“

In order to free up the capacity of laboratory staff for more demanding tasks and to meet the increasing demands on quality and throughput, Eurofins decided to automate pesticide analysis. A success story was found in the sister laboratory: Eurofins WEJ Contaminants had already had good experience with the automated analysis of food samples for mycotoxins. This led to contact with the system integrator Elbatron, which was also commissioned with the customised production for Eurofins. Elbatron has been supporting Eurofins in the industrialisation of individual laboratory analysis since 2016.

Automation means translating processes

A key challenge when designing the automated system was to reduce the complex processes in the laboratory to individual automated motion sequences. „This system was our first automation project, so we had to rethink things a lot“, recalls Dr Alexander Zahm. „At the beginning, we could hardly imagine what the robot could do for us. Together with our partner Elbatron, we approached the solution step by step." In addition, there is the particularly high demand for accuracy in the processes, especially when it comes to dosing, where robots are much less prone to errors than their human colleagues.

The centrepiece of the new system are three ABB IRB 1200 six-axis robots, which, with their large reach and working height, coupled with their large range of motion, are well suited to applications of this type and their dimensions fit well with the size of the robot system. The samples are now processed fully automatically with a high degree of precision and repeatability until the sample extract is ready for measurement.

After the samples have been entered, robots fill the trays, each of which holds ten samples. Up to 200 samples can be processed in one set-up time; a total of up to 400 samples can be processed in 24 hours. After being loaded with sample containers, the trays with the samples travel on a conveyor belt to the dosing station. There, a robot uses a pipette to remove the required amount of liquid – the dosing is accurate to the micrometre. QR codes with information on the type of sample are attached to the sample containers and scanned by the robot. After extraction and the addition of salt, a robot shakes the sample. It is then placed in a centrifuge with a total of 16 places. After centrifugation, a pipetting arm fills the treated sample into the vials. Finally, the laboratory staff only need to remove the ready-to-measure vials.

Fully automated sample preparation

The robot system was designed using the planning software „RobotStudio“. RobotStudio is a key argument in favour of working with ABB, says Rainer Herrmann, Managing Director of Elbatron GmbH, and reports: „We are also particularly happy to make use of the VR function of RobotStudio.“ Elbatron specialists were able to contribute their experience in laboratory automation so that even complicated work steps are now automated, made possible by the flexibility of the ABB robots used. Only the sample input is carried out manually  – the system can then work autonomously for twelve hours without further intervention by the laboratory staff. The system is also designed for 24-hour operation if a growing order volume should make this necessary in the future.

Thanks to their high repeatability and low error rate compared to humans, the robots help the laboratory to reliably comply with strict quality standards. In the manual process, the fluctuation margin of the results was 20 per cent. With the robot-assisted automation solution, this has fallen to less than five per cent - with a higher throughput. The laboratory staff are using the freed-up capacity to further optimise the analysis processes and advance new methods of pesticide analysis. In future, it is conceivable that the facility could be expanded and further steps in the analysis process automated.

The automation solution has fully met our requirements and offers potential for future projects,

said Dr Alexander Zahm.

Article of the "LABO" from 03.05.2023