3. Imagine that more than one band appeared in the GC chromatogram, but you were unable to run the standards. Instead you took the RI and corrected it to 20 oC (1.4205). RI can be used to determine the exact mole percentage of an isomeric mixture.
To determine the exact mole percentage of an isomeric mixture using the Refractive Index (RI), you will need to follow these steps:
1. Obtain the RI value: In this case, you mentioned that the RI was corrected to 20°C and the value obtained was 1.4205. Make sure to note down this value.
2. Create a calibration curve: The first step in determining the mole percentage of an isomeric mixture using RI is to create a calibration curve. This involves running a series of standard mixtures with known mole percentages and measuring their corresponding RI values. By plotting the mole percentages against the RI values, you can create a calibration curve.
3. Analyze your sample: Once you have the calibration curve, it can be used to determine the mole percentage of the isomeric mixture in your sample. Compare the RI value of your sample with the calibration curve and determine the corresponding mole percentage.
Keep in mind that creating a calibration curve by running standards is the most accurate method. However, in your case, you mentioned that you were unable to run the standards. Instead, you have the corrected RI value at 20°C.
To determine the mole percentage without standards, you will need to utilize previously obtained calibration data for the same column and conditions. If you do not have such data, it may be challenging to accurately determine the mole percentage without running standards or using other analytical techniques.