AOAC OMB Meeting Book 2-10-16

AOAC OMB Meeting

Example:   AOAC Official Method 2015.03 

Sodium Fluoroacetate in Infant Formula  Liquid Chromatography‐Tandem Mass Spectrometry  (LC‐MS/MS) 

First Action 2015 

[Applicable for the quantitative determination of sodium fluoroacetate in liquid and powdered milk‐ and  soy‐based infant formulas by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). The limit of  quantification (LOQ) of sodium fluoroacetate is 1 μg/kg by this method. Application of this method to  matrices not covered by the scope of application requires an additional validation.]  Caution: Material Safety Data Sheets (MSDS) should be available for all chemicals; inherent risks and  corresponding safety precautions shall be identified. Follow general safety precautions and environmental  aspects as described in the local Safety, Health and Environment rules in place.  A. Method Performance  The performance criteria in Table 2015.03A is  prescribed by  Standard Methods Performance  Requirements  (SMPR) 2015.001 , which was adopted by the AOAC Stakeholder Panel  for Dietary  Supplements  (SPDS).  Laboratory(ies) implementing this method should follow ISO Standard 17025 to  verify that the performance of this method in your laboratory meets the criteria in table 2015.11A.     Please report verification results to AOAC at this link:   AOAC 2015.03 verification data . 

Table 2015.03A Verification Criteria 

Parameter 

Acceptance criteria 

Analytical Range 

4 ppb – 100 ppm* 

Limit of Quantitation (LOQ)  

≤ 4 ppb* 

Accuracy  

± 20% 

Repeatability (RSDr)   ≤ 14%  * Fluoroacetate expressed as μg of fluoroacetic acid /1000 g of  solids.  

B. Principle  Milk powder is first reconstituted in water. Liquid sample is used as such. Acetonitrile is added to  precipitate proteins. After centrifugation, the supernatant is washed with hexane and then acidified with  concentrated sulfuric acid. QuEChERS salts (MgSO4 and NaCl) are added for phase separation and the  mixture is centrifuged. The resulting supernatant is evaporated to 0.5 mL remaining volume and  centrifuged before LC‐MS/MS analysis in selected reaction monitoring (SRM) by electrospray ionization  (ESI) in negative mode. The compound is analyzed as its fluoroacetate anion.  Quantification is performed by the isotopic dilution approach using 13C labeled sodium fluoroacetate as  internal standard (IS). Positive identification of fluoroacetate in samples is conducted according to the  confirmation criteria defined in EU Commission Decision 2002/657/EC (1). 

February 10-11, 2016

47