3. AOACRIFeedsFertilzerMethods-2018Awards

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384 W EBB : J OURNAL OF AOAC I NTERNATIONAL V OL . 101, N O . 2, 2018

Table 1. Performance criteria requirements and Method 2017.02 results for SRM NIST 695

Table 2. Performance criteria results for Magruder 2009-06 using Method 2006.03 versus Method 2017.02

Parameter Minimum acceptable criteria, % a Method 2017.02 results, % b

Method 2006.03 results, % a

Method 2017.02 results, % b

Parameter

Recovery

Group A: 75 – 120 Group B: 90 – 105

Group A: 75 – 103 Group B: 98 – 103 Group A: 1.3 – 5.2 Group B: 0.8 – 1.9

Recovery

Group A: 95 – 108 Group B: 99 – 149 Group A: 5.7 – 15.2 Group B: 2.1 – 49.8

Group A: 75 – 103 Group B: 98 – 103 Group A: 1.3 – 5.2 Group B: 0.8 – 1.9

RSD r

RSD r

Group A: ≤ 6 Group B: ≤ 3

AOAC Official Method 2017.02: Simultaneous Determination of Arsenic, Cadmium, Calcium, Chromium, Cobalt, Copper, Iron, Lead, Magnesium, Manganese, Molybdenum, Nickel, Selenium, and Zinc in Fertilizers by Microwave Acid Digestion and Argon Inductively Coupled Plasma- Optical Emission Spectrometry Detection, First Action 2017 a Minimum acceptable criteria above are an average of the concentra- tions seen in each group. b The 2017 results above are an average of the concentrations in each group. The individual results fromMethod 2017.02 for each of the 14 metals based on the concentration-dependent guidelines as published in the document above and all results above the LOQ were within the established guidelines. The range of values and the averages are presented in Tables 1 and 2 for the sake of brevity. The calculated recovery and repeatability were determined by comparing the published values on the certificate of analysis from Standard Reference Material 695 purchased from the National Institute of Standards and Technology and the calculations, as in Table 1. The SLV study results demonstrated an acceptable range of repeatability, and, therefore, a full collaborative multilaboratory study will be the next step. Before obtaining Final Action status, the ERP recommended the successful completion of a full multilaboratory collaborative Refer to the published method for further details (1). Discussion

a Results for multilaboratory repeatability are expected to be about 2 times greater for repeatability due to variability in multilaboratory collaborations. b The 2017 results above are an average of each group.

study incorporating the following recommendations: ( 1 ) ask that collaborators add sulfur and sodium to the group B metals using the criteria outlined in the collaborative study packet, ( 2 ) include the SLV results for sodium and sulfur in the final publications, and ( 3 ) perform the repeatability and recovery calculations from the collaborative study and make recommendations based on AOAC INTERNATIONAL ’ s and the Methods Forum performance criteria. (1) Webb, S., Bartos, J., Boles, R., Hasty, E., Thuotte, E., & Thiex, N. J. (2014) J. AOAC Int. 97 , 700 – 711. doi:10.5740/jaoacint.13-408 (2) AAPFCO (2013) Official Publication No. 66 , Association of American Plant Food Control Officials, West Lafayette, Indiana USA, p. 66 (3) Kane, P., & Hall, W. (2006) J. AOAC Int. 89 , 1447 – 1466 (4) Webb, S. (2009) Sim ultaneous Determination of Nutritive and Nonnutritive Metals in Fertilizers by ICP-OES , Proceedings, 123rdAOAC INTERNATIONALAnnual Meeting and Exposition, Philadelphia, PA, September 13-16, 2009 Abstract 1804 (5) Hall, W. (2008) Methods Forum II, Mulberry, Florida, USA (6) (2002) AOAC Guidelines for Single Laboratory Validation of Chemical Methods for Dietary Supplements and Botanicals , https://www.aoac.org/aoac_prod_imis/AOAC_Docs/ StandardsDevelopment/SLV_Guidelines_Dietary_Supplements. pdf (accessed on May 30, 2017) References

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