An Exploration on the Suitability of Airborne Carbonyl Compounds Analysis in relation to Differences in Instrumentation (GC-MS versus HPLC-UV) and Standard Phases (Gas versus Liquid)
Table 2
Comparison of HPLC-based calibration analysis of CC between gas- and liquid-phase standards.
(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
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
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
For 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 L 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 L extract.
(b) HPLC calibration results for liquid-phase CC standard
Concentration
Loading
Peak area
(ng L−1)
mass (ng)a
FA
AA
PA
BA
IA
VA
0.15
3
1,150,435
886,294
606,404
502,987
259,055
358,175
0.30
6
2,137,986
1,584,941
1,247,462
940,570
555,295
666,852
0.60
12
4,243,306
3,183,149
2,388,591
1,987,032
1,391,763
1,425,906
1.20
24
7,763,079
5,875,879
4,646,142
3,691,885
2,922,397
2,786,051
2.40
48
15,043,330
11,578,866
9,202,951
7,322,176
6,099,023
5,976,525
Aldehyde/ketone-DNPH mix (Supelco): liquid phase standard is prepared to have equal mass for all target compounds per unit volume.
