AOAC CASP Cannabinoids ERP October Method Book

the spike solution. Accuracy of all samples met the acceptance criteria, with recoveries ranging from 95 – 268 108% (Table 5). 269 Accuracy data was supported with the analysis of the four in-house reference materials. These 4 270 chocolates were analyzed for precision. Recovered concentrations were compared to theoretical 271 concentrations (based on mass balance of input materials). Recoveries ranged from 91.6 – 99.9% for 272 concentrations up to 1% w/w, and from 95.4 – 96.8% for concentrations >1% w/w (Table 6). Lastly, three 273 of the in-house reference materials were submitted to a different analytical lab to be run using an 274 independent method. Reported concentrations between both labs differed by less than ±5% (Table 6). 275 Taken all together, the confidence in this method’s accuracy is high. 276 The four in-house reference materials from Table 1 were analyzed with 5 replicates each by the same 278 technician on the same day. Average concentrations and percent RSDs can be found in Table 6. 279 Repeatability for all cannabinoids was excellent, with RSDs <3% for concentrations up to 1% w/w, and 280 <0.5% for concentrations >1% w/w. 281 Subsequently, the four in-house reference materials were tested by two technicians on the first day, and 282 then repeated for a second day. Intermediate precision RSD is summarized in Table 6. AOAC SMPR 283 2017.019 (9) did not specify acceptance criteria for intermediate precision and was therefore set to the 284 same criteria as repeatability. Excellent intermediate precision was observed, with RSDs of <4% for 285 concentrations up to 1% w/w, and <2% for concentrations >1% w/w. 286 Linearity, accuracy and precision tests met all necessary acceptance criteria. As such, the instrumental 288 linear range was defined as the instrumental LOQ up to the highest concentration on the calibration curve. 289 Furthermore, the reported linear range for chocolate samples was defined as the instrumental linear 290 range multiplied by the sample’s dilution factor of 125 (i.e., 0.080 g of sample is dissolved in 10 mL of 291 extraction solution). Each analyte’s instrumental range and reported range is found in Table 7. 292 RANGE 287 REPEATABILITY AND INTERMEDIATE PRECISION 277

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STABILITY

The stability of extracted samples was tested by repeated injection of the same HPLC vial, left in the 294 autosampler for 48 hours. Three replicate preparations of the four test materials were injected at 0 hrs, 295 24 hrs, and 48 hrs. The difference between each time point and 0 hrs was calculated to determine if there 296

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