Picogram level quantitation of 2,3,7,8-tetrachlorodibenzo-p-dioxin in fish extracts by capillary gas chromatography/matrix isolation/Fourier transform infrared spectrometry.

For the first time, gas chromatography/matrix isolation/Fourier transform infrared spectrometry (GC/MI/FTIR) has been reported to confirm the identity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD) and to quantify its level in fish extracts in the 170-220 pg range "on disk". When expressed on a fish tissue basis, analyte levels ranged from 15 to 45 pg/g. Spectroscopic identification was based on the position and relative intensity of seven absorption bands. Optical alignment as well as performance evaluation and optimization of the GC/MI/FTIR system are described. The use of [13C12]2378-TCDD as an internal standard was essential for quantitation, and quality assurance controls were used to verify system performance. GC/MI/FTIR quantitation of 2378-TCDD was compared with that independently found by GC with electron capture detection. Recovery of 2378-TCDD averaged 52% (n = 8, 30% relative standard deviation) for fish extracts.