2018 Sugar ERP - Method Review Book

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

The method, as currently written, does not demonstrate that it meets the SMPR Method Performance Requirements. The method also introduces ambiguities and potential reproducibility concerns by leaving the mobile phase concentration up to operator discretion. The method does not achieve adequate resolution of galactose and glucose, which necessitates the use of peak height instead of peak area for concentration determinations. - It is deeply upsetting that the method makes no mention of chemical safety. - Despite being based on RI-HPLC methods that have been in use for decades, the method lists no references/citations - Potential carry-over between samples, particularly those from high fat or high protein matrices, is not addressed - Sample preparation of difficult to grind samples is not addressed, ie. fruit gummies - The method provides no requirements for calibration curve performance such as R2 or residuals criteria - No information is provided regarding using check samples for quality control - Not enough information is provided to insure that the method is free from interferences - It would be nice to have provided standard and sample stability data to support the storage conditions provided in the method - Solutions of 100% water are described as stable for six months stored at room temperature with no concern for microbial growth - It would be preferable for the method to measure all of the analyte sugars over the same analytical range and for all of the analyte sugars to have the same number of calibration standards. Because galactose has only three standard levels, there are potential implications on the accuracy of the resulting calibration curve. - The method repeatability could likely be improved by utilizing the column and temperature control features on the Acquity UPLC system instead of relying on ambient temperatures - It would be beneficial for the method to show a sample chromatogram near the top of the calibration range to properly evaluate the resolution of the galactose and glucose peaks. In the chromatogram that is shown at the lowest calibration standard, there is not baseline separation of the two peaks. - The method would benefit from providing additional data regarding how data was generated for the various aspects of the validation - While galactose is inherently present in dairy products, it is also naturally present in a wide variety of other matrices and it would be beneficial to evaluate its repeatability in other, non-dairy, matrices - In foot-note number eleven, it is noted that repeatability results for the Saco dried buttermilk sample are not reported for lactose because the sample contained lactose at >50% and was not reanalyzed by dilution of the samples to be within linear range of the calibration curve, which raises questions as to why not. As currently written, I do not recommend this method to be adopted as a First Action and published in the Official Methods of Analysis of AOAC INTERNATIONAL because the method does not demonstrate that the SMPR Method Performance Requirements are met. If the method is revised such that sufficient information is provided to demonstrate that the SMPR Method Performance Requirements are met, then I would be willing to reconsider the method for adoption.

7. Any general comments about the method?

V. Final Recommendation 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.