IUPAC, analytical chemistry and our cultural heritage

Considering the explanation of “Who we are” on the web site of IUPAC^[1] I think the following is relevant to the theme of this special edition. “We are a leader in the provision of objective scientific expertise for the resolution of critical global issues that involve every aspect of chemistry, all of which have societal impact”. The cultural heritage of the world belongs to the world, and a world body, such as IUPAC, is needed to provide the intercontinental^[2] understanding that allows open science and sharing of approaches to conserving our important artefacts.

Professor Melo and colleagues writing the preface to the papers in this issue quote Louis Pasteur “(…) il n‘est pas possible de bien conserver ce que l’on connait mal”. Not being able to conserve what we do not know echoes the wider motto of many National Measurement Institutes “You cannot manage what you cannot measure”, and so the thesis of my contribution is that analysis (including analytical chemistry) is the essential platform of our ability to conserve.

Cultural heritage studies require skills from all of chemistry. Analytical chemistry certainly but also a deep knowledge of materials and their properties when part of an object that might be exposed to the environment, or in contact with other strange substances. Perhaps more so in a highly cross-disciplinary field accurate terminology allows scientists, students of the arts and historians to have a discourse that leads to the desired outcomes, namely the conservation of our cultural heritage. To underline this point, we have decided to also publish in this issue a Technical Report in which measurements of mass or volume used in chemistry are described and terms defined [1].

The mass and volume report will become a chapter in the forthcoming, completely new, edition of the IUPAC Orange Book (Compendium of Terminology in Analytical Chemistry) edited by the author.^[3] In it we shall see a recrafted terminology of analytical chemistry, which focusses on the methodology of analytical chemistry, rather than the applications. This decision was largely taken because the uses of analytical chemistry are now so many and varied – witness the fascinating papers in this edition of PAC – it would not be possible to give an account of all of analytical chemistry as it is used. However, we have attempted to provide a coherent terminology of modern methodology in analytical chemistry. Adding the names of the many varieties of NMR, or the new techniques of bioanalytical chemistry turned out to be the easy part. What has caused the most discussion is deciding the formal definitions of fundamental concepts of the subject – what is ‘analytical chemistry’?^[4]

IUPAC has contributed to, and been a major player in, the Joint Committee for Guides in Metrology, the international body that produces the International Vocabulary of Metrology (VIM) [2] and the Guide to the expression of Uncertainty in Measurement (GUM) [3]. Making sense of correct, but occasionally hard to understand, terms and definitions and interpreting them for the chemical community has been a long and interesting activity. The importance of using the correct word to describe accurately the concept that is in our mind cannot be overstated. We have an excellent example in the field of cultural heritage. Professor Melo has drawn our attention to the connotations of the use of the words ‘destructive’ (Portuguese destructiva; Italian distruttivo) and non-destructive, in relation to sampling for conservation purposes. The image of a rampant analytical chemist chopping up a priceless painting or statue in order to say what it is made of is not a pretty thought. Finding alternative terms (with translations) and then persuading the community to use those terms (and give up deprecated terms) is a task made easier when the terminology comes with the imprimatur of the world body IUPAC, and having been through the scrutiny of the process of publishing IUPAC Recommendations. I therefore invite the community of chemists working in conservation and heritage to work on a project that will give a comprehensive terminology for the field.

I have been interested to read all the articles in this special issue of PAC, in particular the work on conserving bronzes. Many years ago I was asked to analyse the washings of a campaign to clean two bronze equestrian statues^[5] outside the Art Gallery of New South Wales in Sydney Australia. Close by Sydney Harbour, the marine atmosphere had created a patina of copper chloride salts (visible in the photograph) which it was deemed had to be removed. Glycine was being used and while the statues were looking cleaner we were monitoring the dissolution of significant amounts of copper. All went well however and happily the statues are still there.

Bronze sculpture by Gilbert Bayes “Offerings of Peace” (left side of facade) inscription: “The Real and Lasting Victories Are Those of Peace and Not of War”. Art Gallery of New South Wales Accession no. 3254. Creative Commons Attribution-Share Alike 4.0 International licence. Author Whiteghost.ink