Validation for the MAT-CH procedure

Prof. Dr. Alexandra Jeberien has set up both tests side by side. The difference between the old and the new equipment is striking: the wobbly plastic stand on the left contains small test tubes with yellowish silicone stoppers which require the attachment of hand-cut metal plates - a delicate operation. By contrast, the solid metal frame on the right boasts conveniently sized flasks with glass stoppers and integrated glass hooks used to hang up the test plates with ease thanks to a handy drilled hole. “Everything is ready to use,” comments the scientist, pleased with the product’s successful development. Now all that needs to happen is the scientific validation of the pollutant test for museums, collections and archives. Prof. Dr. Jeberien has applied for additional funding for this.

Emissions could harm cultural assets

Alexandra Jeberien’s work deals with nothing less than the protection of valuable cultural assets, archaeological metals and glass, for example, or natural historical specimens, coins, technical devices and historical photos and films. After all, these assets are all exposed to a variety of emissions in showcases, cabinets and packaging materials. “Wooden display cases, for instance, can release organic compounds such as terpenes, aldehydes as well as acetic and formic acid which is absorbed by the exhibits,” she comments. In depots, on the other hand, where 90 to 95 per cent of the holdings from museums, collections and archives are stored, the storage conditions or packaging often cause problems for the objects.

The test used to date has various weaknesses

In order to assess the risks, museum experts have been using the Oddy indicator test, named after its developer Andrew Oddy, since the 1970s: the Oddy test. But because there are now more than twenty variations of this test in circulation worldwide, the results are neither comparable nor reproducible. In addition, the platelets made of the pure metals silver, copper and lead, key components of the Oddy test, can only be used once, which is neither sustainable nor efficient, not to mention costly. Reason enough for Prof. Dr. Jeberien to further develop the outdated test procedure in the context of the MAT-CH research project.

A new test yields better results and saves time

The scientist has made good progress. HTW Berlin holds a European patent for the project, developed in cooperation with the glass technology workshop Glastechnische Werkstatt Naskowski. The impractical silicone stopper was replaced by a glass equivalent, and the volume of the flask was increased so that more sample material fits inside. Thin metal-coated and drilled indicator plates made of glass, which can be hung on the hooks of the reaction vessels, replace the metal plates made of silver, copper and lead, which previously had to be cut manually and cleaned at great expense before use. “This results in enormous time savings,” says Prof. Dr. Jeberien happily - not to mention the greater sustainability. In addition, the results are easier to compare because the coated glass plates are industrially produced and shrink-wrapped.

Test runs have already been successful

Test runs with familiar test materials have already shown that the coatings of the glass plates have the correct thickness, density and roughness. They react to the sampled materials, but do not do so too early, so they can be ordered by museum staff at their leisure and stored for specific periods of time.

Serial tests for validation in the lab

Before the prototypes made @HTW Berlin can be produced in larger quantities, Prof. Dr. Jeberien must provide scientific proof that the test equipment she has further developed produces the same results as the tried and tested Oddy test. This requires serial tests for about 200 different materials, five sample containers per material, in order to satisfy the prerequisites of statistical relevance. The experiments must take place under specific laboratory conditions and the results must be systematically evaluated. “This is basic research,” says the scientist, and she has once again applied for funding for it. The Institute of High-Frequency and Semiconductor System Technologies of TU Berlin and OUT e.V. are back on board as cooperation partners.

A database to support museum staff

Beyond the validation of the tests, Prof. Dr. Jeberien envisages the development of a database including images of the corrosion which has occurred, i.e. a kind of image and reference catalogue that will help museum staff to evaluate the sample results. In addition, she wants not only to visually document the respective corrosions and oxidations on the glass plates, but also scrutinise them metrologically. This is less relevant for museum practice, but scientifically interesting, she says. The catalogue, of course, also benefits from greater accuracy. If everything goes well, the marketing of the new test equipment can start shortly thereafter. And Prof. Dr. Jeberien intends to optimise the evaluation procedure in a third sub-project. “There is still room for improvement,” she says, agreeing with many critics as she does so.

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