CONTRIBUTION OF ENZYMATIC METHOD FOR ANALYZING SUCROSE AND STARCH IN TRADITIONAL CHINESE LIME- AND EARTH-BASED MORTARS

摘要

Brown sugar and sticky rice were frequently used as organic additives in Chinese mortars. This study applied enzymatic spectrophotometric methods to identify sucrose and starch contents in traditional Chinese lime- and earth-based mortars. The focus was to understand and evaluate the qualitative detection capacity of enzymatic method in mortars, by first applying the method on a series of lab-prepared mortar specimens with specific amounts of brown sugar and sticky rice addition, then on historic mortar samples suspected to contain brown sugar and sticky rice. The potential contribution and limitations of enzymatic method in analysis of sucrose and starch in mortars was compared with other common available analytical methods. The results suggested that for lab-prepared brown sugar mortar specimens, enzymatic method was more sensitive and exclusive than chemical method, and particularly had higher detection capacity in lime mortars. For simulated mortars with sticky rice addition, enzymatic method showed no distinct detection capacity differences among the studied inorganic binders and comparing with chemical methods was more sensitive in earth-based mortars. Enzymatic analysis on historic mortar samples was able to distinguish some false-positive results from the chemical and FTIR analysis, which was then corroborated by SEM.