GC-MS Data Analysis

1. From your report, find the retention times and peak areas for all four fragments in each sample, then create a table in Excel that looks something like the table below, and then fill in your values. (You may need to add rows if any m/z value has more than one peak).

2.  From the information in the Introduction, determine which m/z values in your table correspond to which species (BPA or IS), and which m/z values you should use to calculate your BPA/IS ratio.

3.  From step A in the Method, calculate the BPA concentration added in each 25-mL volumetric flask.

4.  Make a new table in Excel that looks like the following and fill in each value:

5. Make a standard additions plot of the ratio (y-axis) vs the concentration of BPA added (x-axis). Show a trendline through the points, as well as the equation of the trendline and the R2 value.

6. Recalling that the x-intercept of your standard additions plot gives you the concentration of BPA in the 25-mL flask to which no standard was added, consider dilutions to calculate the concentration of BPA in the original water sample.

7.  To determine if the internal standard was important, make a plot of the BPA peak area (instead of the BPA/IS ratio) vs the concentration of BPA added.  Compare the R2 values of each.

8.  Submit your data and results in the Report Form on LabArchives.