Final answer:
If the sample's signal is beyond the linear range of the calibration curve, dilute the sample to fall within the linear range. Use the dilution equation to calculate the necessary volume of the stock solution required to achieve the desired concentration, and check your answers for reasonableness.
Step-by-step explanation:
If the signal from the sample solution is beyond the linear area of the calibration curve, you should dilute the sample so that its signal falls within the linear area. This is because the accuracy of the concentration determination is dependent on the linearity of the calibration curve. Working outside of this linear range may give rise to inaccurate results. Diluting the sample ensures that you can use the established relationship provided by the calibration curve to accurately determine the concentration.
It's not recommended to use the linear fit equation to extrapolate data beyond the linear range or to try different fitting equations until the answer seems right, as these approaches can lead to erroneous results.
When preparing dilutions, it is crucial to perform calculations using the dilution equation that relates the concentration of the stock solution and the desired concentration after dilution. The equation is: C1V1 = C2V2, where C1 is the stock concentration, V1 is the volume needed from the stock solution, C2 is the desired concentration, and V2 is the final volume of the diluted solution.
Always check your answer to confirm that it makes sense and is within the expected range. Doing so can help to catch any potential mistakes made in the calculations or methodology.