Analysis of 19 PCB congeners in catfish tissue using a modified QuEChERS method with GC-MS/MS.

A simple approach to determine 19 PCB congeners in catfish tissue was presented. A modified QuEChERS method employing high solvent to sample ratio 10:1 was used to improve the extraction recovery of 19 PCB congeners. After salting out by shaking with anhydrous magnesium sulfate and sodium chloride, 1 mL of acetonitrile extract was pipetted into a 2-mL centrifuge tube containing anhydrous magnesium sulfate, primary secondary amine sorbent, and C-18 sorbent. The tube was then shaken and centrifuged to absorb fat and fatty acid residue present in the acetonitrile extract. The acetonitrile extract was analyzed by GC-MS/MS. The excellent sensitivity of GC-MS/MS allows for the direct injection of the samples to detect the low level of the PCB congeners. The method therefore is high throughput, uses fewer consumable lab supplies, and provides excellent sensitivity with an LOQ below 1 ng/g.