AOAC Final Action Methods in 2018

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 )

© 2015 AOAC INTERNATIONAL