AOACSPIFANMethods-2017Awards

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E llingson et al .: J ournal of AOAC I nternational V ol . 99, N o . 1, 2016  209

respectively (Table 3). The average results obtained from the analysis of NIST SRM 1849a were within the certified ranges or close to the information mass fraction value. Only an information mass fraction value is given for free choline, although there is currently nothing provided for total carnitine from NIST. The average total recoveries (endogenous + added) shown in Tables 4 and 5 for all matrixes tested from LOQ to the upper ranges required in the SMPR were 95.9–103.6%. Analysis of bound sources of carnitine and choline analyzed in duplicate over 3 days gave average recoveries of 104.6% for acetylcholine, 96.7% for phosphatidylcholine, and 104.1% for acetylcarnitine. The level of detection (LOD) was determined by the mean baseline noise + (3 × SD) from 10 blank replicates, and then adjusted with the default weights and dilutions used in the method. An LOD of 0.0034 mg/100 g for both free and total carnitine analyses and an LOD of 0.0047 mg/100 g for both free and total choline analyses were achieved. An LOQ of 0.05 mg/100 g was obtained for both free and total choline and carnitine. The LOQ was calculated from the lowest working standard concentration through the default weights and dilutions used in the method. The analytical range of the method is from the stated LOQ to 250 mg/100 g choline and 20 mg/100 g carnitine and is supported by the data collected from the precision and accuracy experiments. This method meets all

requirements of AOAC SMPRs 2012.010 and 2012.013 for l -carnitine and total choline, respectively; the only exception is an inability to distinguish between l - and d -carnitine with this method.

References

(1) Standard Method Performance Requirements (2013) J. AOAC Int . 96 , 488, AOAC SMPR 2012.010 . doi: 10.5740/jaoac.int. SMPR2012.010 (2) Standard Method Performance Requirements (2013) J. AOAC Int . 96 , 492, AOAC SMPR 2012.013. doi: 10.5740/jaoac.int. SMPR2012.013 (3) Starkey, D.E., Denison, J. E., Seipelt, C. T., Jacobs, W. A., & Dowell, D. (2013) J. AOAC Int . 96 , 1082–1085. doi:10.5740/ jaoacint.13-140 (4) Martin, F., Gimenez, C., Fontannaz, P., Kilinc, T., Campos-Giménez, E., & Dowell, D. (2013) J. AOAC Int . 96 , 1396–1399. doi:10.5740/jaoacint.13-195 (5) Oates, K., Chen, L., De Borba, B., Mohindra, D., Rohrer, J., & Dowell, D. (2013) J. AOAC Int . 96 , 1400–1406. doi:10.5740/ jaoacint.13-177 (6) Ellingson, D., Pritchard, T., Foy, P., King, K., Mitchell, B., Austad, J., Winters, D., Sullivan, D., & Dowell, D. (2013) J. AOAC Int . 96 , 1068–1072. doi:10.5740/jaoacint.13-128