Hi all,

I have read a Semi-quantitation method for SVOC extractables by GCMS. In the method, an external calibration line is created by five different dilution of Phenanthrene, 1-50mcg/ml. The internal standard is Phenanthrene-d10. Surrogate standards, e.g. octamethylcyclotetrasiloxane, cyclohexanone, are also prepared in different concentration from 0.15-15mcg/ml.

The concentration of analyte's concentration is provided by using the response from surrogate substances, specially accounting for the relative responses of analyte and the surrogate.

I'm not familiar with this kind of semi-quantitative method. I hope that some of you can give me the explanation, the purpose of using internal, external, and surrogate standards in this case, and how the analyte's concentration is calculated.

Thank you for your attention and have a good day!