Compound-specific hydrogen isotope composition of n-alkanes in combustion residuals of fossil fuels

The hydrogen isotope compositions (delta D) of n-alkanes present in the combustion residuals of fossil fuels (coal, gasoline, and diesel) were measured using GC-IRMS to distinguish between coal soot and vehicle exhaust. The n-alkane delta D values of industrial and domestic coal soot ranged from -95.3 parts per thousand to -219.6 parts per thousand and -128.1 parts per thousand to -188.6 parts per thousand, respectively, exhibiting similar tendencies. The delta D values of the C-15-C-18 n-alkanes in both types of coal soot were nearly consistent, and the delta D values of the C-19-C-24 n-alkanes exhibited a zigzag profile. The delta D values of C-16-C-22 n-alkanes in gasoline exhaust exhibited a saw-tooth distribution, decreased with the carbon number, and were more positive than the delta D values of C-16-C-22 n-alkanes in diesel exhaust, which increased with the carbon number. However, the delta D values of the C-23-C-29 n-alkanes in gasoline and diesel vehicle exhaust were mostly consistent. The weighted average delta D values of the C-16-C-19 n-alkanes in industrial and domestic coal soot were similar to the average delta D values in gasoline and diesel vehicle exhausts; however, the average delta D values of the C-21-C-29 n-alkanes in vehicle exhausts were richer in D than those in coal soot. (C) 2014 Elsevier Ltd. All rights reserved.