Environmental Article

Resolving Benzo(j)fluoranthene from Other PAHs

Using a Pinnacle II PAH Column

By Robert Freeman, Environmental Innovations Chemist

Resolve 16 priority pollutant PAHs to baseline.
Fully resolve benzo(j)fluoranthene.

Numerous chromatographic methods are used to detect or quantify polycyclic aromatic hydrocarbons (PAHs) in solid or liquid matrices. For example, US EPA Method 610 includes analysis of 16 priority PAHs by either gas or liquid chromatography. GC/MS is commonly used for qualitative identification, however many PAHs are not completely resolved by GC and must be separated by HPLC. In addition to the 16 priority pollutants in this method, another PAH, benzo(j)fluoranthene, is currently being added to some expanded PAH scans. In GC analyses benzo(j)fluoranthene usually co-elutes with benzo(b)fluoranthene, but it can easily be resolved by HPLC.

Many HPLC methods for analyzing PAHs recommend an octadecyl silane (C18) stationary phase. We selected the Pinnacle II PAH HPLC column—a specialized polymeric C18 bonding that uses unique shape selectivity to completely resolve all 16 US EPA priority pollutant PAHs. To demonstrate the capabilities of this column, we used our EPA 8310 reference standard (cat. #31841), which contains two additional PAHs (1-methylnaphthalene and 2-methylnaphthalene) as well as the 16 priority pollutants. We also included benzo(j)fluoranthene in our analyses.

Generally a UV detector at 254 nm is used for this analysis. Figure 1 shows successful separation of all 19 PAHs — including benzo(j)fluoranthene — with detection at 254 nm. A fixed detector wavelength of 254 nm provides sufficient sensitivity for most PAHs, however, the optimal wavelengths for each PAH over a 200-400 nm scan using a photodiode array detector (PDA) are shown in Figure 2.

Even greater sensitivity can been achieved by coupling UV and fluorescence detection. Matrix interference can be minimized since few compounds naturally fluoresce and the fluorescence detector is much more sensitive than UV at low levels. Because PAHs fluoresce at different wavelengths, an emission wavelength program was used for each analyte, at various excitation wavelengths.

All 16 priority PAHs - as well as 1-methylnaphthalene, 2-methylnaphthalene and benzo(j)fluoranthene - can be fully resolved by HPLC, using a Pinnacle II PAH column.

Figure 1 Nineteen polycyclic aromatic hydrocarbons fully resolved using a Pinnacle II PAH column.

Peak	Ret. Time (min.)	Peak	Ret. Time (min.)
1. naphthalene	5.99	11. benzo(a) anthracene	13.06
2. acenaphthylene	6.89	12. chrysene	13.36
3. 1-methyl naphthalene	7.51	benzo(j) fluoranthene	14.36
4. 2-methyl naphthalene	7.83	benzo(b) fluoranthene	14.71
5. acenaphthene	8.18	benzo(k) fluoranthene	15.22
6. fluorene	8.50	benzo(a) pyrene	15.75
7. phenanthrene	9.29	dibenzo(a,h) anthracene	16.51
8. anthracene	10.00	benzo(ghi) perylene	17.03
9. fluoranthene	10.82	indeno(1,2,3-cd) pyrene	17.28
10. pyrene	11.34

LC_EV00416
Sample:
Inj.:	10µL
Conc.:	20µg/mL each component
Sample diluent:	acetonitrile
Column:	Pinnacle II PAH (cat.# 9219563)
Dimensions:	150 x 3.2 mm
Particle size:	5µm
Pore size:	110Å
Conditions:
Mobile phase:	A) water	B) acetonitrile
	Time (min.)	%B
	0	40
	7	60
	16	100
	18.9	100
	19	40
Flow:	1.2mL/min.
Temp.:	30°C or ambient
Det.:	UV @ 254nm

Figure 2 Polycyclic aromatic hydrocarbons on a Pinnacle II PAH column, using a PDA detector.

Peak	Wave- length (nm)	Ret. Time (min.)	Peak	Wave- length (nm)	Ret. Time (min.)
1. naphthalene	218	5.99	11. benzo(a) anthracene	286	13.06
2. acenaphthylene	228	6.89	12. chrysene	266	13.36
3. 1-methyl naphthalene	222	7.51	benzo(j) fluoranthene	223	14.36
4. 2-methyl naphthalene	222	7.83	benzo(b) fluoranthene	255	14.71
5. acenaphthene	226	8.18	benzo(k) fluoranthene	237	15.22
6. fluorene	205	8.50	benzo(a) pyrene	295	15.75
7. phenanthrene	249	9.29	dibenzo(a,h) anthracene	296	16.51
8. anthracene	249	10.00	benzo(ghi) perylene	298	17.03
9. fluoranthene	235	10.82	indeno(1,2,3-cd) pyrene	248	17.28
10. pyrene	239	11.34

LC_EV00417
Sample:
Inj.:	10µL
Conc.:	20µg/mL each component
Sample diluent:	acetonitrile
Column:	Pinnacle II PAH (cat.# 9219563)
Dimensions:	150 x 3.2 mm
Particle size:	5µm
Pore size:	110Å
Conditions:
Mobile phase:	A) water	B) acetonitrile
	Time (min.)	%B
	0	40
	7	60
	16	100
	18.9	100
	19	40
Flow:	1.2mL/min.
Temp.:	30°C
Det.:	UV-PDA