289 / 471
© 2015 AOAC INTERNATIONAL
Table 2014.08H. MS ions (
m
/
z
) and MS/MS precursor to product ion transitions used by study participants for quantification
(quant) and identification (qual) of target PAHs and
13
C-PAHs using single-stage MS (single quadrupole and TOF) and tandem MS/MS
(triple quadrupole) instruments, respectively
Single quad/TOF MS
Triple quad MS/MS
Compound
Quant
Qual
Quant
Qual
1,7-DMP
206
191
206>190
206>205, 206>165
1-MN
142
115
142>115
142>141, 142>116
1-MP
192
189
192>191
192>165
2,6-DMN
156
141, 144
156>115
156>141
3-MC
242
241
242>239
242>226
Ant
178
177
178>176
178>177, 178>151
BaA
228
226
228>226
228>224, 228>202
BaP
252
253
252>250
250>248, 252>224
BbF
252
253
252>250
250>248, 252>224
BghiP
276
277
276>274
274>272, 276>275
BkF
252
253
252>250
250>248, 252>224
Chr
228
226
228>226
228>224, 228>202
DBahA
278
276
278>276
276>274, 278>274
Fln
166
165
166>165
166>164, 166>163
Flt
202
200
202>200
202>201
IcdP
276
277
276>274
274>272, 276>248
Naph
128
127
128>102
128>127
Phe
178
177
178>176
178>177, 178>151
Pyr
202
200
202>200
202>201
13C-Ant
184
183
184>183
184>182, 184>156
13C-BaA
234
232
234>232
234>206
13C-BaP
256
257
256>254
256>228
13C-BbF
258
259
258>256
258>255
13C-BghiP
288
289
288>286
288>287
13C-BkF
258
259
258>256
258>255
13C-Chr
234
232
234>232
234>206
13C-DBahA
284
282
284>282
284>280
13C-Fln
172
171
172>171
172>170
13C-Flt
208
205
208>206
208>207
13C-IcdP
282
283
282>280
282>281
13C-Naph
134
133
134>133
134>105
13C-Phe
184
183
184>183
184>156
13C-Pyr
205
203, 206, 208
205>203
205>204
ratios of contemporaneously analyzed calibration standards, which
have been analyzed under the same conditions.
(
c
)
Injection sequence.
—Bracket the seven test samples with
two sets of calibration standards. Inject solvent blanks after the
calibration level 8 (highest) standard and after the samples. In
addition, analyze a reagent blank with each set of samples. Inject
only once from each vial, thus preventing potential losses of
volatile PAHs and/or contamination.
H. Calculations
Quantification is based on linear least-squares calibration of
analyte signals (
S
PAH
) divided by signals (
S
13C-PAH
) of corresponding
13
C-labeled internal standards (
see
Table
2014.08I
) plotted versus
analyte concentrations. Peak areas are generally preferred as signals
used for the quantification, but peak heights should be used for
peaks that are not well resolved, such as in the case of anthracene
and phenanthrene. The analyte concentrations in the final extract
(
c
PAH
, µg/L) are determined from the equation:
c
PAH
= [(
S
PAH
/
S
13C-PAH
) –
b
]/
a
where
a
is the slope of the calibration curve and
b
is the
y
-intercept.
The concentration of PAHs in the sample (
C
, µg/kg) is then
calculated:
C
= (
c
PAH
/
c
13C-PAH
) × (
X
13C-PAH
/
m
)
Candidates for 2016 Method of the Year
230