AOAC-RI ERP Book - FAOM METHOD.pdf

Table 5. Reference Mass Fraction Values for Selected PAHs in SRM 1974c Mass Fraction (a) (μg/kg)

k

Wet-Mass Basis 0.990 r 0.039 1.41 r 0.03 1.50 r 0.06 0.913 r 0.007 1.19 r 0.02 0.206 r 0.006 0.860 r 0.008 0.523 r 0.007 0.343 r 0.019 0.451 r 0.014 1.32 r 0.02 2.02 r 0.04 5.95 r 0.05 2.07 r 0.01 0.100 r 0.001 0.490 r 0.010 19.2 10.1 r 0.5 r 0.1

Dry-Mass Basis 9.66 r 0.39

Naphthalene (b,c)

1.96 1.97 1.97 2.09 1.97 1.97 1.97 1.96 1.97 2.57 2.57 2.09 2.09 2.57 2.09 2.09 2.57

1-Methylnaphthalene (b,c) 2-Methylnaphthalene (b,c) 1,2-Dimethylnaphthalene (b,c) 1,6-Dimethylnaphthalene (b,c) 2,6-Dimethylnaphthalene (b,c)

13.7 14.6

r 0.3 r 0.6

8.91 r 0.10

11.6

r 0.2

2.01 r 0.06 8.39 r 0.10 5.11 r 0.08 3.35 r 0.18 4.40 r 0.14

Biphenyl (b,c)

Acenaphthylene (b,c) Acenaphthene (b,c)

1-Methylfluoranthene (d,e) 3-Methylfluoranthene (d,e)

12.9

r 0.2

Chrysene (d,e)

187

r 5

Triphenylene (d,e)

98.5 19.7 58.0 20.2

r 1.6 r 0.4 r 0.7 r 0.2

4-H-Cyclopenta[ def ]phenanthrene (d,e)

Benzo[ b ]fluoranthene (d,e) Benzo[ j ]fluoranthene (d,e) Dibenz[ a,c + a,h ]anthracene (d,e) Dibenzo[ b,k ]fluoranthene (d,e)

0.976 r 0.016 4.78 r 0.11

2.57 (a) Mass fractions are reported on both wet- and dry-mass basis; material as received contains 89.75 % r 0.08 % (95 % confidence level) water. (b) GC/MS (Ia) using SPE clean-up followed by analysis on a DB-17MS column using EI-MS and GC/MS (IIa) using SPE and SEC clean-up followed by analysis on a DB-XLB column using EI-MS. (c) The reference value reported on a wet-mass basis is a weighted mean of average mass fractions, with one average each from two analytical methods [3,4]. The expanded uncertainty is the half width of a symmetric 95 % parametric bootstrap confidence interval [5], which is consistent with the ISO Guide [6,7]. The effective coverage factor k is included in the table for each PAH. (d) GC/MS (IIa) using SPE and SEC clean-up followed by analysis on a DB-XLB column using EI-MS. (e) The reference value reported on a wet-mass basis is the mean of results obtained using one analytical technique. The expanded uncertainty, U , is calculated as U = ku c , where u c is one standard deviation of the analyte mean, and the coverage factor, k , is determined from the Student’s t -distribution corresponding to the associated degrees of freedom and a 95 % confidence level for each analyte.

SRM 1974c

Page 7 of 9