My sample had d10-ethylbenzene in it, I thought it would be clean?
d10 Ethylbenzene is not actually a target parameter but a chemical added to your sample.
It is used as a surrogate and is added to your sample during the analytical process to monitor the efficiency of organic extractions, instrument performance and provide within-run quality control.
Surrogates such as d10-ethylbenzene are deuterated analogues or compounds not normally found in nature but have chemical and physical behavior similar to the analytes of interest. Known surrogate concentrations are added to samples prior to analysis and recoveries are calculated and expressed as a percentage.
Ethylbenzene is an organic compound and common ingredient of gasoline, occurs naturally in coal tar and petroleum and used in the production of polystyrene.