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

yes, but would like to see a sample blank for comparison

yes

yes

1. specificity for Theanine 2. meets SMPR requirements for Theanine (LOQ, analytical range)

1. Single source (Pickering Labs) of mobile phase (Li-citrate buffer), cation-exchange column, and post-column derivatization reagent 2. Post-column derivatization system - only one from Pickering demonstrated; not sure what other options are out there for use and if they would be similar enough to generate equivalent results 3. analysis time (ca. 62 minutes injection to injection) 4. did not see sample blank injections; in particular interested to see if any co-elution with ISTD (L-norleucine) in some of the samples where there appear to be other small peaks eluting nearby 5. method applicable to Theanine only; other analytes of interest in Tea will require a separate method (but don't see how this can be avoided) 6. identification of potential interferences from various sample matrices eluting near ISTD (e.g. in green tea softgels)?

7. Any general comments about the method?

post-column derivatization does add some complexity and potentially impact detection limits; however, method results appear to suggest this is not a limitation here

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.

Yes Need multiple lab date to demonstrate how this method performs in unaffiliated lab environment in order to demonstrate ease of use, reproducibility, and applicability on different post column derivatization systems