In the fixed-time method, what is the first step after combining the reactants?

In the fixed-time method of enzymatic or chemical assays, the initial step after combining the reactants is to allow the reaction to proceed for a designated time. This step is crucial because it ensures that there is sufficient time for the reactants to interact and produce a measurable amount of product. The length of this time period is predetermined and is critical to ensuring that the reaction is within a linear range, allowing for accurate and reproducible measurements.

Following this step of letting the reaction proceed, subsequent actions such as stopping the reaction, measuring the amount of product, or taking absorbance measurements would occur based on the protocol of the specific assay. The fixed-time method is typically designed to measure the amount of product produced at a specific interval, reflecting the reaction’s progression during that pre-established timeframe. Therefore, allowing the reaction to proceed appropriately sets the stage for accurate analyses in the later steps.