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1. What is the maximum number of sample positions?

999 sample positions are freely programmable on Metrohm Sample Processors.

2. Why should I consider automation?

Automation not only increases productivity but also offers the following benefits

· Mundane and laborious tasks are performed exactly the same each and every time

· Equipment may be run for many hours without operator intervention

· Accuracy may be improved , certainly when discussing pipetting and diluting

· Hazardous tasks such as additions of solvent or corrosive materials may be completed with minimum human exposure

· Complex tasks can be completely automated

· Sample preparation tasks may be automated.

3. How is cross contamination prevented between samples?

The rinsing and cleaning of the electrode, burette tips and rod stirrer after a titration is essential to avoid any cross contamination with future samples. This equipment is rinsed efficiently by very fine water droplets from three spray nozzles. The waste and rinsing solution is aspirated off completely. It is important to stress that these rinsing and aspirating times can be changed, for example, one may want to aspirate the sample totally then spray and aspirate simultaneously for say 10 seconds and then aspirate only for a further 5 seconds. Special beakers can be assigned to each separate sample rack, which enables the correct, ongoing routine electrode maintenance to take place between titrations and of course at the very end of the automated sample run.

4. I wish to make some dilutions to my samples can this be incorporated into my sample routine?

Pipetting is a complicated sample preparation procedure, but fortunately it can be fully automated. One no longer needs to bother with the time consuming measuring out of the sample, as the high accuracy of the Dosino simplifies this task. The Dosino works with a volume resolution of 10,000 steps per burette volume, equal to 0.2 of a micro litre for a 2 ml Dosing Unit, and sample volumes of 0.010 ml to 100 ml can be handled with unbelievable precision.

An air gap is produced prior to pipetting up the sample, which stops any contamination between the sample, and the rinsing or diluting solution. This method also stops any cross-contamination between samples. Dilutions of samples can play a vital part in these sample preparations. A defined volume of solvent is added to an exactly measured out volume of sample. The preparation of serial dilutions or standard solutions with different concentrations is still essential in the analytical methods used today. No matter if it is ion chromatography, voltametry, ICP or atomic absorption spectrostroscopy; these techniques all rely on making dilutions. The Metrohm Sample Processors carry out this task with the highest degree of precision, far exceeding the accuracy obtained by traditional pipettes and volumetric flasks.

5. My samples are solids; can they be mixed prior to its analysis to make sure they dissolve?

The sample can be mixed prior to the analysis and or it can be homogenised if required.

Homogenizing a sample presents a challenge in an automated system, as frequently a propeller or magnetic stirrer is not able to mix and dissolve the sample completely. Certain samples such as tablets must first be pulverized before the determination to release the substances of interest.

Sample size reduction and homogenization can be carried out, for example, with the Polytron 1300 D homogenizer from Kinematica. To trigger the required actions, transfer commands are used to send defined three-digit numerical codes to the control unit of the homogenizer. Not only can the instrument be switched on and off, its speed can also be set in the range 7000...30,000 rpm. It is also possible to vary the speed of rotation within the method sequence to adapt it to the particular conditions. For instance, the sample can be disintegrated at 25,000 rpm with the subsequent determination taking place at 7000 rpm.

If the 786 Swing Head of the Robotic Sample Processor is equipped with the Robotic Arm then the homogenizer can even be used with multiple-row sample racks. This means that large sample series can be processed without any problem.

Between determinations the homogenizer can be cleaned automatically by one of two methods. The stirrer is either immersed in a special beaker containing a rinsing solution (e.g. water/ethanol mixture) and switched on briefly, or cleaning can be carried out using the spray nozzles built into the titration head of the Robotic Arm.

In both cases carryover is reliably prevented.

6. Temperature is critical for applications; can I hold the temperature constant?

Yes. Metrohm can offer thermostated sample racks of differing sample numbers and sizes where the temperature can be held between -10 C and 50 C.

7. Can different methods and calibration routines be incorporated into a sample queue?

As many different methods, calibration and standardisation methods can be incorporated. All sample queues are freely programmable.

8. Can I automate my Karl Fischer titrations?

Metrohm can automate KF titrations whether it be volumetric or coulometric titrations and or in conjunction with an oven for the analysis of “difficult” samples.