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Analyzing various parameters in petroleum products is one of the most frequent requests in contract or quality control laboratories. Automation has gained popularity in the last decade due to the high number of tests required along with the use of aggressive solvents and reagents. Combined automated benchtop-based systems are available, but these still require operators to perform many manual steps. This blog article gives an example of an automated system that goes beyond the benchtop, offering users total hands-free analysis from start to finish.

Benefits of automating chemical analysis

There are many benefits to gain when changing from a stand-alone laboratory setup to a fully automated system. A quick summary of these can be made using the application example of analyzing the total acid number (TAN) and total base number (TBN) in petroleum products.

Aggressive solvents and titrants must be used for the determination of TAN and TBN in oils. Automating all steps that include handling of these reagents results in a much safer work environment for lab technicians by eliminating exposure to the chemicals and their vapors. 

Automated liquid handling for addition of the solvent or titrant has a direct impact on the quality of results. This is especially true for TAN/TBN analysis. Precise solvent addition is critical, as the solvent can impart a blank value which falsifies the result if not considered during the analysis. By automating this step, it is guaranteed that each addition is carried out in the exact same traceable manner.

Adding as many analysis steps as possible to the automatic procedure helps lab personnel in many ways. This leads to more accurate and precise results and saves a significant amount of time as the system can run unattended around the clock with a continuous sample load. Furthermore, fewer errors mean a reduction in samples that need to be repeated, making the workflow even more efficient.


Read our related blog article to learn about the benefits of automating titration analyses.

Why consider automation – even for simple titrations

Going one step farther with robotics

The automation of the sample dilution, analysis, evaluation, and electrode cleaning/conditioning already helps many contract and quality control laboratories to maintain a high level of efficiency. However, there is still room for more improvement. Automating the complete workflow—from the moment the closed sample vial is brought into the system to the results evaluation and cleaning—is the next logical step.

The system provided by KA Industrial Engineering Pte Ltd with Metrohm is a robotic setup using a collaborative Universal Robot in combination with the well-known OMNIS Sample Robot to completely automate the analysis of TAN and TBN (Figure 1). The entire system is controlled by OMNIS software. 

Figure 1. Completely automated analysis of TAN and TBN in petrochemical products is possible using this robotic system provided by KA Industrial Engineering Pte Ltd with Metrohm.

Once the sample is introduced to the system, the robotic arm performs various sample preparation steps. This arm is equipped with several tools to manage the different, and usually tiresome, manual tasks.

Fully automated robotic analysis of TAN and TBN in petrochemical samples

The robotic analysis system shown in Figure 1 is designed for complete autonomy—saving time, increasing sample throughput, reducing effort, and improving the safety of daily operations in quality control or contract laboratories.


The automated workflow consists of the following steps:

  1. The sample vial is picked up and identified by its barcode.
  2. The vial is placed on a vortex shaker to homogenize it before a representative sample is taken.
  3. The cap of the sample vial is removed while the robotic arm places a clean titration beaker on the balance and picks up a fresh pipette tip to avoid any cross-contamination.
  4. The sample is aspirated while the balance is tared to prepare for the measurement of the added sample to the beaker.
  5. The sample weight is automatically transferred to the OMNIS software that controls the complete setup.
  6. The vial is closed and put back into its original position.
  7. The beaker with the sample is transferred to the OMNIS Sample Robot where the potentiometric titration takes place at one of the available workstations.
  8. Before the titration takes place, the titration equipment is cleaned and the sensors are preconditioned to guarantee optimal results.
  9. Once the sample beaker is mounted in the workstation, the solvent is added automatically to reduce contact with aggressive chemical reagents.
  10. After the titration is complete, the beaker is automatically emptied, and the equipment cleaned.
  11. The results are calculated and transferred to the connected LIMS system.


Titer and blank determination as well as sensor calibration and check samples can be easily added to the workflow if desired. The OMNIS software controlling the setup offers everything to keep the system running and to immediately inform the operator in case of limit violations.

Due to both robots working in synchronicity, the next samples are already prepared while previous ones are determined, guaranteeing constant high throughput. The presented system in Figure 1 works with two parallel workstations. This can easily be upgraded to a system that can handle up to four workstations running with the same or even different applications.

This robotic system from the partnership of Metrohm and KA Industrial Engineering Pte Ltd offers a completely traceable workflow which includes many security features. For high throughput completely automated sample analysis and minimal contact with aggressive reagents, this robotic system is the optimal choice.

Seeing is believing—watch the video below to see the next step in robotic automation of chemical analysis.

Conclusion

After many years of proposing benchtop automation for all analysis techniques Metrohm offers, we have gone a step beyond this into the development of lab robotics. Now it is possible to offer systems that can completely handle the entire workflow, including sample preparation and determination. The discussed system is just one example of such an approach for the robotic analysis of TAN and TBN in petroleum products. 

Author
Risse

Heike Risse

Head of Competence Center Liquid Handling and Lab Robotics
Metrohm International Headquarters, Herisau, Switzerland

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