Metrohm Saves Time for Panel Testing at Unilever

Introduction 'Panel Testing' plays an important part in the development of many household products notably fabric washes and conditioners.

Introduction 'Panel Testing' plays an important part in the development of many household products notably fabric washes and conditioners.

The preparation of these washes for housewife testing is often time consuming and laborious, since the formulations are normally diluted in some way, and prepared with precision.

Often the same formulation is repeated over 300 times and with up to 10 components in each formulation such an exercise can take up to 3 days to complete, thus tying up a person for a very long time.

Unilever, a leading manufacturer of such products, has recently purchased 4 automated systems from Metrohm UK to perform this time consuming procedure.

Utilising the 730 Autosampler, 700 Dosinos and TiNET Software, the customer is able to produce these formulations within a day, with much greater precision and also allows the technician to carry out other important tasks at the same time.

pH adjustment can be made by using a Titrino's SET mode.

Formulations from Microsoft Excel Spreadsheets are automatically transferred into the samplechanger silo for increased speed and improved accuracy.

The components are added in various amounts from as low as 0.1 ml up to 200ml.

Larger and lower additions can be made with the same equipment if required.

The System In Detail.

The system consists of a 730 Sample Changer with one (or two) work station, three 729 Dosimat Interfaces, ten 700 Dosinos, a 731 Relay Box with a 772 Pump.

TiNET 2.4 is used to control the instruments.

The sample changer rack accommodates 12 x 150ml glass bottles (one of which is used as a cleaning/aspirating bottle situated in special position 1 (position 12).

The titration head is equipped with a 722 stirrer, tridispense tips, and the normal 'spin rinse'/aspirate tubes.

A titrino can be attached to a second workstation where pH adjust, for example, takes place.

Overview Of TiNET Method.

Using Dosino 1 a defined volume of component A is dispensed directly into the first bottle and is swiftly followed by component B from Dosino 2, then component C from Dosino 3, etc, etc, until the formulation is complete.

Any solids are preweighed into each bottle prior to addition of the liquids.

After addition of all the components the 722 stirrer is switched on for approximately 15 seconds.

Rinsing and aspirating takes place in the bottle at special position 1 by the normal inbuilt pump on the 730 Sample Changer (Rinse) and the 772 Pump (Aspirate).

The clean titration head then moves to bottle 2 and the cycle begins again.

Total cycle time is approximately five minutes.

Transfer Of Formulation Data.

The manual input of the formulations into the sample silo memory could be seen to be time consuming.

Thousands and thousands of formulations of this sort had been carried out by hand for many years, and a large database of such formulations were (and still are ) stored on Microsoft Excel Spredsheets.

These formulations are effortlessly exported from their existing format directly into the sample silo memory via TiNET 2.4.

The first step is to save the Excel Spreadsheets as a.TXT file, this file is then closed.

The next step is to open up the 'Titration' part of TiNET and open up a Worksilo, pick out the relevant file name and look at all file types.

After OK ing the formulation, the relevant sample information is directly imported into the sample silo.

Solutions added via the Dosinos include; Nonionic surfactants and soap Anionic surfactants Enzymes Citrate Alcohol Foam Regulators Auxillaries Optical brighteners Perfume oils Silicates Water Solids are weighed into the bottles prior to dispensing the liquids.

Instruments Used.

2.730.0010 Sample Changer (1 station and 1 pump).

2.729.0010 Dosimat Interface 2.700.0010 Dosino 2.722.0020 Stirrer 2.731.0010 Relay Box 2.772.0010 Pump 6.6012.140 TiNET 2.4 Acknowledgements.

Many thanks go to Dr Vincent C Mole, Senior Scientist, Unilever Research, Port Sunight, Wirral, CH63 3JW (e-mail: vincent.mole@Unilever.com) in allowing us to publish this article.

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