Chromatography Forum

I have a method for GC-MS all set up and ready to GO.

I have made a calibration curve of 5,10,20 and 30ppm of Compound A.

Each standard is made as follows:

Using 2000ppm stock solution of standard of compound A.

0.125ml into 50ml = 5ppm
0.250ml into 50ml =10ppm
0.5ml into 50ml = 20ppm
0.75ml into 50ml = 30ppm.

Sample made as follows:

50mg of ‘Sample’ into 50ml and run against the standards

I what to calculate ‘Compound A’ from the 50mg ‘sample’

What is the calculation to calculate 'Compound A' in the 50mg of sample dissolved in 50ml please?

Sorry for easy question, but I am new to GC-MS and would like to learn more please.

Many Thanks in advance

Your instrument software should give you the concentration of compound A (=x) in the 50mL, and should be between 5-30ppm provided it's within the calibration.

If it doesn't calculate it, you need the peak areas which you plot against the concentration of standards in a program like MS Excel. Apply a fit to obtain a calibration curve. If linear, the curve will give an equation of y=ax+b. Put the sample peak area as y to obtain x.

Now x is the concentration in 50mL (mg/L = ppm). For example 12mg/L. The final result in ppm (mg/kg) sample is 12mg/L * 0.050L/0.000050kg = 12000ppm = 12mg of compound A in 1g sample.

Thank you for you help.

This helps greatly....

Thank you for you help.

This helps greatly....