Quantitation of PCB Congeners in Human Serum
Using GC/NCI MS

Abstract:
Polychlorinated biphenyl (PCBs) remain public health concerns because of their unresolved health impact and their persistence in human and the environment.

Since these compounds are considered as endocrine disruptors in wildlife and have the potential to affect sexual and neurobehavioral development and function in humans, a methodology has been developed for the routine determination of specific polychlorinated biphenyl (PCBs) congeners in human serum.

The method involves solid-phase extraction (SPE) and cleanup followed by a quantitation based on calibration standards and response ratios using isomers #114; #189 and #202 as internal standards.

The PCB congeners are determined by mass spectrometry in negative ion chemical ionization mode. For congeners of high chlorination (penta through deca), the method exhibits excellent sensitivity which allows a limit of detection of 20 fg (0.01 ng/ml; 2 uL injection). The negative chemical ionization is not as sensitive for mono through tetrachlorinated PCBs, an exception being PCB#77, for which sensitivity is of the same order as for the more highly chlorinated biphenyls.

Recoveries of 26 fortified PCB congeners ranged from 60 to 104%.

The current method is being used routinely to analyze human serum samples in a study designed to assess potential human health effects from exposure to PCBs, including the non-ortho-substituted PCB congeners (#77, #126 and #169).