(a) Calibration of gas-phase CC standard by HPLC/DNPH cartridge method
| Order | FA | AA | PA | BA | IA | VA |
|---|---|---|---|---|---|---|
| Concentration of CC standard (ppb) for 5-point analysis | ||||||
| 1 | 96.1 | 65.1 | 13.1 | 12.2 | 12.8 | 9.90 |
| 2 | 194 | 132 | 26.6 | 24.6 | 25.9 | 20.0 |
| 3 | 387 | 264 | 53.0 | 49.2 | 51.9 | 40.0 |
| 4 | 773 | 527 | 106 | 98.0 | 104 | 80.0 |
| 5 | 1,559 | 1,058 | 213 | 198 | 208 | 160 |
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| Calculated mass (ng) of CC injected into HPLCa assuming no losses in derivatization and extraction | ||||||
| 1 | 3.79 | 3.79 | 1.01 | 1.16 | 1.46 | 1.12 |
| 2 | 7.58 | 7.58 | 2.02 | 2.31 | 2.91 | 2.24 |
| 3 | 15.2 | 15.2 | 4.03 | 4.63 | 5.83 | 4.49 |
| 4 | 30.3 | 30.3 | 8.06 | 9.26 | 11.7 | 8.98 |
| 5 | 60.6 | 60.6 | 16.1 | 18.5 | 23.3 | 18.0 |
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| Peak area | ||||||
| 1 | 1,430,395 | 882,104 | 114,854 | 164,484 | 74,796 | 80,079 |
| 2 | 2,754,983 | 1,733,480 | 222,048 | 297,748 | 146,260 | 177,013 |
| 3 | 5,650,140 | 3,472,465 | 577,168 | 640,128 | 375,504 | 449,499 |
| 4 | 11,240,906 | 6,552,152 | 1,007,331 | 1,059,943 | 728,865 | 894,010 |
| 5 | 22,526,453 | 12,305,560 | 1,718,513 | 1,742,954 | 1,454,395 | 1,660,223 |
aFor each calibration point, 8 L of gaseous CC standard is sampled by the cartridge and these CCs are extracted by 5 mL acetonitrile. As 20 μL of extract is injected into HPLC, the actual mass (ng) of CC loaded onto HPLC is computed as the total quantity of each CC contained in 20 μL extract.