A new method for detecting sticky rice in ancient mortar based on ELISA

As a common organic additive in organic–inorganic composite mortar, sticky rice significantly augments the strength, toughness, and waterproof properties of the mortar. In China, sticky rice mortar has been used for more than 1,500 years. However, the traditional iodine-starch method cannot achieve quantitative detection, and the colour of the mortar itself interferes with detection results, causing failures in detecting trace amounts of sticky rice in cultural relic samples. In this paper, we present a new approach where extracting and purifying protein from sticky rice and subsequently the enzyme linked immunosorbent assay (ELISA) is used to recognize sticky rice in the mortar. The studies performed showed that the ELISA detection limit based on sticky rice is two orders of magnitude lower than that of the iodine-starch method and can identify traces of sticky rice in mortar.