Fanick, E. Robert, et al. SAE Technical Paper, 2017-01-2393.
Semivolatile organic compounds (SVOCs) are a class of compounds found in engine exhaust that are usually present at very low concentrations. This work employs an improved dilute exhaust sampling method for sampling and analyzing SVOCs in engine exhaust, which is performed during transient engine operation.
SVOCs, present at trace levels in exhaust, were collected using XAD-2 resin to target volatile fractions across sampling, extraction, and analytical phases. Each XAD sampling unit comprised five traps containing 100 g of resin, spiked with a dual-component surrogate (9-methylanthracene-d12 and 1,8-dimethylnaphthalene-d12) to monitor procedural losses and calculate recovery rates. Prior to extraction, deuterated polycyclic aromatic hydrocarbon (PAH) internal standards were introduced into both volatile and particulate phases to facilitate precise quantification of target PAHs, with specific concentrations detailed in accompanying tables.
A total of 22 SVOCs were successfully measured, revealing significantly higher concentrations in untreated exhaust compared to systems equipped with aftertreatment technologies. Phase distribution analysis demonstrated that SVOC partitioning between semivolatile and particulate phases correlated with molecular characteristics, including aromatic ring count, molecular weight, and volatility.
