Forensic Science, salivary amylase, Amplex Red, saliva detection, fluorimetry, body fluids detection, serology, Biology (General), QH301-705.5

A new sensitive method for saliva detection was developed, based on salivary amylase detection but with a final fluorescent product, which increases its sensitivity. After the starch is degraded due to the presence of salivary amylase, glucose is oxidised and generates hydrogen peroxide which is able to transform Amplex Red in resorufin - a highly fluorescent product. The final product is visible both under normal and UV light. The method is fast, accurate, can detect trace amounts of saliva and shows little to no interference with other body fluids. A further increase in sensitivity could be obtained by using horseradish peroxidase in the final step, but this would also lead to an increased background signal and stronger interference with urine.