SPSFAM EXPERT REVIEW PANEL

4. Based on the supporting information, is the method written clearly and concisely? If no, please specify the needed revisions. 5. Based on the supporting information, what are the pros/strengths of the method? 6. Based on the supporting information, what are the cons/weaknesses of the method?

Yes. The method protocol is clearly written.

• IAC is of high specificity, which can significantly reduce interference in chromatography system and the chance of false-identification. • HPLC-FLD is relatively affordable and easy to operate. • The method could be easily adopted by various laboratories.

• IAC column is relatively costly. It also seems very delicate and susceptible to extreme conditions i.e. low pH and high content of organic solvent. Thus additional steps are required for sample preparation (e.g. adjusting the pH, reducing the portion of methanol in sample solution, filtration of sample), which increases the complexity of method and could introduce more errors. • In order to meet the LOD/LOQ requirement, sample concentrating step was performed for juice matrix. The blow-drying and the reconstitution are time-consuming. • Authors did not indicate the unit of LOD and LOQ in table 1, but presumably it is in ppb? • Accuracy was evaluated by spiking the samples. However, authors did not provide information on sample blank. I would like to know whether recovery was calculated by sample spike subtracting sample blank. • I would recommend to replace the filtration step in juice preparation to centrifugation. Methanol may evaporate during the filtration, and causes inaccuracy in volume measurement.

7. Any general comments about the method?

Do you recommend this method be adopted as a First Action and published in the Official Methods of Analysis of AOAC INTERNATIONAL? Please specify rationale.

I would recommended to make decision after reviewing the data on system suitability and analytical qualify control which authors failed to provide.