Determination of dibenzopyrenes in standard reference materials (SRM) 1649a, 1650, and 2975 using ultrasonically assisted extraction and LC–GC–MS

Abstract

A method has been developed for analysis of the highly potent polycyclic aromatic hydrocarbon (PAH) carcinogens dibenzo(a,l)pyrene, dibenzo(a,h)pyrene, and dibenzo(a,i)pyrene (molecular weight 302) present in small amounts in diesel and air particulate material. The method can also be used for analysis of the PAH benzo(a)pyrene, coronene, and perylene, for which reference and certified values are available for the standard reference materials used for validation of the method--SRM 1649a (urban dust) and SRM 2975 (diesel particulate matter). The only NIST values that have been published for these dibenzopyrene isomers in the analyzed SRM are reference values for dibenzo(a,i)pyrene and dibenzo(a,h)pyrene in SRM 1649a. The concentrations determined in the SRM were in good agreement with reported NIST-certified and reference values and other concentrations reported in the literature. Standard reference material 1650 (diesel particulate matter) was also analyzed. The method could not, however, be validated using this material because certification of SRM 1650 had expired. The method is based on ultrasonically assisted extraction of the particulate material, then silica SPE pre-separation and isolation, and, separation and detection by hyphenated LC-GC-MS. The method is relatively rapid and requires only approximately 1-5 mg SRM particulate material to identify and quantify the analytes. Low extraction recoveries for the analytes, in particular the dibenzopyrenes, when extracting diesel SRM 2975 and 1650 resulted, however, in the dibenzopyrenes being present in amounts near their limits of quantifications in these samples. The method's limit of quantification (LOQ), based on analyses of SRM 1649a, is in the range 10-77 pg. By use of this method more than 25 potential PAH isomers with a molecular weight of 302 could be separated.

Dibenzopyrenes, other PAHs with molecular weight 302, and selected carcinogenic PAHs seldom determined: identification and one-year quantification in urban air

“…Figure 1 shows the November chromatogram as an example, with 21 peaks marked: the eight isomers we identified using authentic standards and 13 tentatively identified by comparison with the gas chromatogram of the SRM 1649a 'Urban dust' reported by Schubert et al [5] and by Bergwall and Westerholm [7]. The profile we found matched well with the SRM profile found by these authors, with only two differences: (a) Schubert et al found a shoulder (marked as no.…”

“…[5] (superscript S) or in ref. [7] (superscript B) and the BaP concentration certified by NIST [13]. studies at sites with a range of possible source mixtures, it could support BaP as a suitable marker of occurrence not only of the 'classical' carcinogenic PAHs but also of the potent carcinogen DBalP and, more generally, of the three carcinogenic DBPs.…”

“…Since the earlier findings of the highly potent experimental carcinogenicity of dibenzo[a,l]pyrene [1][2][3], the determination of this compound and of other polycyclic aromatic hydrocarbons (PAHs) with MW 302 in environmental matrices has drawn the attention of various investigators [4][5][6][7][8][9]. The unambiguous identification of these PAHs is a difficult task owing to the combination of their low concentrations in the environment and the co-presence of several isomers with MW 302 possibly interfering when using conventional gas chromatography (GC) or high-performance liquid chromatography (HPLC) columns.…”

“…Regarding the DBP determination in air samples, only a few published studies adopted strict analytical procedures allowing interferences to be controlled. According to these studies, the four DBPs were determined in air samples collected in Stockholm [8], in the Standard Reference Material (SRM) NIST 1649a constituted by urban particulate matter collected in Washington [5,7,13], and (except DBalP) in the SRM NIST 1648 constituted by urban particulate matter collected in St. Louis, MO [4]. DBaiP and DBaeP were identified, and the latter quantified too, in air samples collected in Boston [14].…”

Time to Say Goodbye to the 16 EPA PAHs? Toward an Up-to-Date Use of PACs for Environmental Purposes

“…Are they frequently recorded or only rarely, and are they very (site-)specific compounds? Above, the dibenzopyrene isomers were mentioned as highly toxic PAHs that may be relevant for inclusion on any list of environmentally significant PAHs, but up to today no more than some 40 studies report the detection of these compounds in environmental samples: their presence in the environment has been shown in vehicle exhaust (31)(32)(33)(34)(35)(36)(37), air particulate matter (36,(38)(39)(40)(41)(42), house dust (43), coal tar (31,40,44), coal extracts (7), automobile tires (45), particulates from coal combustion (46,47), fly ash (48), sediment and soil (31,40,(49)(50)(51)(52)(53)(54)(55), cigarette smoke (34), and exhaust gases from sewage sludge incineration (56).…”