SPSFAM Heavy Metals ERP Book

ARTICLE REVIEW CHECKLIST

Review of J. AOAC (2017) 100(4):1-9 First action method 2016.04 for arsenic in fruit juice

by

Robert A LaBudde

[It is not clear why review of a published article is needed here. – RAL]

OVERALL REVIEWER OPINION:

Repeatability was not measured appropriately under repeatability conditions. Instead, pseudo- repeatability was measured. As repeatability is part of reproducibility, reported reproducibility is also then suspect. True repeatability and reproducibility variation are likely larger than values reported from the study.

ABSTRACT:

1. The non-standard definitions of LOD and LOQ should be mentioned in Abstract. 2. The language “In general, repeatability and reproducibility of the method was ≤15% RSD for …” is not easily interpreted. Should have been “relative standard deviation of repeatability RSD(r) and reproducibility RSD(R) for the method were less than 15% for ...”. 3. 95% confidence are not reported for standard deviations and recovery.

COLLABORATIVE STUDY:

4. It is not clear what a test portion (TP) for the study was. Apparently a relatively large quantity (TP?) was send to each lab for each matrix and that TP was analyzed multiple times (pseudo-replicates). This is not repeatability conditions as defined by AOAC. The so-called ‘repeatability’ statistics reported in Table 1 are not correct. Also note that pseudo-replicates where neither randomized nor masked.

TABLE 1:

5. It should be clearly stated that the ‘number of replicates’ is, in fact, the total number of replicates. 6. The ‘repeatability’ statistics are actually ‘pseudo-repeatability’ and should be omitted or correctly denoted.

DATA REPORTING AND STATISTICAL ANALYSIS:

7. Using both Dixon and Grubbs’ tests for outliers is incorrect, unless the proper corrections for multiple comparisons is made.

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