The Metrohm 855 Robotic Titrosampler sample processor is an autotitrator and sample changer on which complex sample processing and analysis can be carried out.
It measures the pH of high-viscosity samples such as hair removal creams, mascaras, eye-gels, suntan creams, cream foundations and toothpastes, then thoroughly rinses the electrode clean of contamination, on sample racks of up to 100 sample places.
It performs automatic electrode and stirrer rinsing in a rinsing station outside the sample rack, fed by high-velocity jets which blast contamination from the electrode with water, hot if necessary, or another solvent.
It has a propeller stirrer for optimal rinsing solution agitation that can change stirring direction as many times as necessary and peristaltic pumps for removing solid contamination.
Using Tiamo controlling software, bespoke rinsing protocols can be written for each sample type to ensure all contamination is removed.
The electrode is mounted on a swing-arm - after sample measurement the electrode swings to the external rinsing station.
The only stirring occurs in the rinsing station, so the issues associated with immersing the stirrer in each sample and subsequent rinsing requirements are eliminated.
The Metrohm 855 is a combination of the Titrando sample processor and Tiamo titration software.
The combination of automation and titration saves up to 40 per cent of the normally required space.
It performs the following titration modes: dynamic titration (DET), monotonic titration (MET), titration to a preset endpoint (SET), enzymatic and pH-STAT titration (STAT).
The direct measurement of concentrations of a wide range of ions is also possible - the standard addition technique for ion-selective measurements is available as an additional mode.
With the Dosino dosing unit - up to three Dosinos can be controlled simultaneously - the titrant or an auxiliary solution can be added at a high volume resolution.
This titrant monitoring feature prevents the use of incorrect or even expired solutions.
The Metrohm 855 also carries out pipetting - this consists of taking a defined portion of the sample solution, transferring it to an external titration vessel and carrying out the determination.
This is also where the electrode rinsing is carried out.
The control of the titrating sample changer takes place via a USB connection.
System control can be carried out in the following ways: computer-independently with touch control, with PC Control 4.0 computer control software or with Tiamo 1.3 titration and automation software.
The Metrohm 855 can be bought as a complete package for analysis of up to 140 samples or in stages.
The complete package is equipped with a work station including a 786 swing-head for high sample throughput.
The built-in membrane pumps and the external peristaltic pump carry out everything from demanding rinsing procedures up to conditioning the electrodes.
The basic version with basic equipment can be extended to become the complete system.
It is equipped with the work station and 786 swing-head as well as built-in membrane pumps and the corresponding pump connections for peristaltic pumps.
An additional peristaltic pump and external rinsing station are required for pH measurement.
