[itsbourne]

Hi,

We analyze concentrations of Polycyclic aromatic hydrocarbons (PAH) using GC-MS. We use deuterated PAHs (DPAH) as internal standards. For standard calibration curve I prepare a mixture of PAH and DPAH stock.

Will the concentrations change due to mixture, because when i run DPAH stock individually the concentration is different when run with mixture of PAH. All dilutions and calculations were checked thoroughly. This happened few time.

Any suggestions.

Thanks in advance