Abstract
Protein additives (e.g. milk, eggs, animal glue, and curd) have been added to mortars since ancient times because they positively influence their mechanical properties. However, historical recipes did not survive until today, because they were only orally inherited in the families of masterbuilders from father to son.
Today, building industry and also restorers search for the forgotten ancient recipes and chemists struggle with many challenging obstacles in their revealing. Nowadays we can use mass spectrometric techniques (MALDI-TOF and LC-MS/MS) for identification of even unexpected proteins in historical mortars.
For the estimation of total amount of protein additives in mortars we can apply different analytical methods including mass spectrometry and immunochemical techniques. Immutability in number of peptides (after enzymatic cleaving by trypsin), in model mortar samples that were sampled from the first day to fourth year after the mortar preparation, was confirmed by LC-MS/MS and relative quantification method TOP3.
By principle component analysis applied on another type of sample (but having an analogy to mortar samples) was proven that it is possible to distinguish between different times of ageing. This at least theoretically could be used as another way for object dating.