Simultaneous detection of multiple hydroxylated polychlorinated biphenyls from a complex tissue matrix using gas chromatography/isotope dilution mass spectrometry

• The study investigated 3–8 chlorinated OH-PCBs in liver and brain samples by GC–MS.
• New pretreatment method was more efficient than sulfuric acid treatment.
• Good recovery and accuracy was proven by recovery test in wide range of OH-PCBs.
• The peaks of 15 and 29 OH-PCB congeners were identified in the brain and the liver.

In this study, we developed a comprehensive, highly sensitive, and robust method for determining 53 congeners of three to eight chlorinated OH-PCBs in liver and brain samples by using isotope dilution gas chromatography (GC) coupled with electron capture negative ionization mass spectrometry (ECNI-MS). These results were compared with those from GC coupled with electron ionization high-resolution mass spectrometry (EI-HRMS). Clean-up procedures for analysis of OH-PCBs homologs in liver and brain samples involve a pretreatment step consisting of acetonitrile partition and 5% hydrated silica-gel chromatography before derivatization. Recovery rates of tri- and tetra-chlorinated OH-PCBs in the acetonitrile partition method followed by the 5% hydrated silica-gel column (82% and 91%) were higher than conventional sulfuric acid treatment (2.0% and 3.5%). The method detection limits of OH-PCBs for each matrix obtained by GC/ECNI-MS and GC/EI-HRMS were 0.58–2.6 pg g−1 and 0.36–1.6 pg g−1 wet wt, respectively. Recovery rates of OH-PCB congeners in spike tests using sample matrices (10 and 50 pg) were 64.7–117% (CV: 4.7–14%) and 70.4–120% (CV: 2.3–12%), respectively. This analytical method may enable the simultaneous detection of various OH-PCBs from complex tissue matrices. Furthermore, this method allows more comprehensive assessment of the biological effects of OH-PCB exposure on critical organs.