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United States Department of Agriculture

Agricultural Research Service

Title: Determination of Total Fat in Milk-Based Infant Formula Powder by Supercritical Fluid Extraction

Authors
item Wolf, Wayne
item Lacroix, Denis

Submitted to: Association of Official Analytical Chemists Peer Verified Method
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 31, 2003
Publication Date: February 28, 2003
Citation: Wolf, W.R., Lacroix, D.E. 2003. Determination of total fat in milk-based infant formula powder by supercritical fluid extraction. Association of Official Analytical Chemists Peer Verified Method. 2:2002, J. AOAC International, 86(1), 86-95.

Interpretive Summary: Using a commercially available Supercritical Fluid Extraction (SFE) instrument, a method has been developed and a collaborative study carried out for the determination of total fat in milk-based infant formula powders. A Data Quality Objective (DQO) approach has been used to evaluate the performance characteristics of the method. The DQOs include: Accuracy - Obtaining correct values for SRM-1846 Infant Formula (NIST); Precision - RSD of less than 2.8% (within Horwitz "limits of acceptability"); Ruggedness- Parameters characterized included extraction time, extraction flowrate, sample size, and amount of modifier (50% alcohol); and Scope of applicability- Milk based infant formula. Excellent reproducibility of inter-laboratory data between FCL and two collaborating laboratories was obtained. This peer validated study and is being submitted to AOAC-International as an AOAC Peer-Verified Method. This method will be useful to food testing and analysis laboratories in the private and governmental regulatory sector which are interested in high volume gravimetric determinations of total fat in infant formula and are interested in eliminating costly organic solvent disposal problems involved in current routine methodology for these determinations.

Technical Abstract: Using a commercially available Supercritical Fluid Extraction (SFE) instrument, a method has been developed for the determination of total fat in milk-based infant formula powders, which eliminates costly solvent disposal problems. A Data Quality Objective(DQO)approach has been used to evaluate the performance characteristics of the method. The DQOs include: Accuracy -Obtaining correct values for SRM-1846 Infant Formula (NIST); Precision - RSD of less than 2.8% (within Horwitz "limits of acceptability"); Ruggedness- Parameters characterized included: extraction time, extraction flowrate, sample size, and amount of modifier (50% alcohol); and Scope of applicability- Milk based infant formula. Excellent reproducibility of data between FCL and two collaborating laboratories was obtained in a peer validation study, which involved distribution of samples of the SRM and two commercial infant formula products to each laboratory. The use of clearly defined DQO's and a commercially available reference materials in the validation studies allows this method to be comparably validated for future implementation by other labs. This peer validated study is being submitted to AOAC-International as an AOAC Peer-Verified Method.

Last Modified: 10/23/2014
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