Spotting tiles: small tests, separate samples and clear observations
Understand how separate test wells preserve sample identity, timing and colour evidence during amylase endpoint sampling.
A spotting tile gives small samples separate places to be tested. Each well holds a separate test. It cannot measure the sample volume or identify the reagent. In an amylase investigation, each fresh test position represents a sample taken at a recorded time.
The amylase practical guide explains the full sampling method. The teacher specifies the reagents, volumes and interval. A tile used for another reaction may need different materials, precautions and cleaning.
Map each well to a sample
Before sampling, agree a direction across the tile and record how wells correspond to tubes and times. To judge when the reaction reached its endpoint, you must know which sample produced each colour and when it was taken.
The Practical Biology activity uses successive samples tested with iodine on a tile. Keep the test reagent outside the reaction tube and use a fresh position for each test. Returning tested material would change the reaction mixture.
Keep wells separate during transfer. Follow the prescribed small quantities and work close to the tile to limit splashing. “One drop” is an instruction within a specified method, not a universal calibrated volume from any dropper.