AOAC_SPDS_ERP_-_Set_3

2. Does the method contain system suitability tests or controls as specified by the SMPR? If not, please indicate if there is a need for such tests or controls and which ones. 3. Is there information demonstrating that the method system suitability tests and controls as specified in the SMPR worked appropriately and as expected? If no, please specify. 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?

Yes. A blank check sample could be added to comply with SMPR.

Consider modifying the statements about retention times to include an acceptable % deviation with a specified number of replicate injections.

Yes.

Yes. I would add more guidance under the section for sample preparation to assist in choice of sample size and extraction volume. Something like "Choose sample size corresponding to approximately X mg of theanine".

The method is simple and straightforward (sonication extraction, chromatography, detection).

The method has demonstrated accuracy via use of reference materials as well as spike/recovery studies.

The method has demonstrated adequate precision as specified in the SMPR.

The method has adequate linearity, LOQ, and LOD as stated in the SMPR.

6. Based on the supporting information, what are the cons/weaknesses of the method?

High marginal spike/recovery for liquid green tea product (108.7%).

The post-column reactor may be considered "specialized equipment".

Unknown how method would respond to gummies/chewables (2 difficult matrices). Sonication extraction might not be sufficient.

Ruggedness tests showed sensitivity of the method to the ratio of sample mass to extraction solution volume and also post-column reactor temperature. Adding a statement to the sample preparation section can assist with the selection of appropriate sample size and extraction volume, to reduce likelihood of such issues. In addition, a statement could be added to the apparatus section regarding calibration of the post- column reactor temperature. Very good method for determination of theanine. While it doesn't meet the full applicability of the SMPR, it is promising as a method for theanine and could be used in conjunction with another method for the other analyte classes. The method is a strong candidate, but without understanding of how the method will behave with gummies and chewables (2 difficult matrices that were specifically indicated as important by the working group), I do not recommend that this method is adopted as first action at this time.

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 recommend that the authors conduct additional studies using gummy and chewable supplements and resubmit, as the method has demonstrated potential.