Polycyclic Aromatic Hydrocarbon Analysis

The concentrations of 16 PAHs [nathphalene, acenaphthylene, acenapthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(ghi)pyrlene, and indeno(123cd)pyrene] were quantified in the serum samples. Samples of 0.10 mL of serum were subjected to liquid–liquid extraction using the approach of Sirimanne et al²¹ that employs cloud-point extraction to preconcentrate, extract, and cleanup the PAHs from human serum. The resulting samples were then analyzed by gas chromatography/mass spectrometry (ThermoScientific TRACE GC/DSQ MS).

The separations were performed using an Rxi-XLB-fused silica column with a low polarity proprietary phase. The column dimension was 30 mm ×0.25 mm ID ×0.25 μm df. It exhibited extremely low bleed, ideal for PAHs analysis. The inlet temperature was 220°C. Samples are injected with splitless injection. High-purity He was used as the carrier gas and kept constant at 1.2 mL/min. The GC oven initial temperature was 60°C and held for 1 minute, then the temperature was increased to 210°C at 12°C/min, then to 320°C at 8°C/min, and the final temperature was held for 10 minutes. The specific conditions for the MS were as follows: EI with Secondary Ions Mass-positive mode. The filament emission current was set at 70 μA. MS transfer line temperature was set at 300°C and ion source temperature at 200°C. Five-point calibration PAH standard mixtures were run to determine the instrument response factors. The resulting chromatograms and mass spectra were inspected to ensure proper peak integration and the peak areas were the converted to concentrations using the response factors and the known surrogate recoveries. The PAH concentration results were then reported as ng of each detected PAH per mL of serum.