AOAC OMB Final Action Recommendation (December 2019)-2016.14

2016.14 (Jan. 2019) FOS-03 MLT Report FOR ERP USE ONLY DO NOT DISTRIBUTE

Method Fructans in Infant Formula & Adult Nutritionals by Anion-Exchange-Chromatography with Pulsed Amperometric Detection after Enzymatic Treatment Caution: The method employs corrosive (sodium hydroxide, acetic acid) and toxic (sodium azide) chemicals. Use appropriate personal protective equipment when performing testing. Refer to the materials safety data sheets and take appropriate additional safety precautions for handling and waste disposal. Principle Samples are reconstituted in water (if required) and further diluted until the concentration of fructan in solution is such that after hydrolysis the fructose and glucose concentration is within the range covered by the standard curve. The diluted sample is treated with a mixture of sucrase and α-glucanases to hydrolyse sucrose and alpha-glucooligosaccharides to their constituent monosaccharides. The sample is passed through a SPE column packed with graphitized carbon. Salts and monosaccharides pass through and are washed away, while the fructans are retained. Fructans are released from the column using an acetonitrile solution. The released fructans are hydrolysed with an inulinase mixture, and the released glucose and fructose are analysed by high performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The fructan content is calculated by summing the glucose and 0.9 × the fructose content measured. In some matrices containing low amounts of fructans, a blank correction may be necessary and can be applied. A. (c) Microtubes. —1.5-mL & 2-mL. (d) Floating rack for microtubes. (e) Water bath. —Able to maintain 80 °C ± 1 °C, with magnetic stirring if available. (f) Water bath. —Able to maintain 40 °C ± 1 °C. (g) Microcentrifuge. —Able to operate at 10 000 x g . (h) Micropipettes. —With tips (0.1 to 1) mL. (i) Vortex mixer . (j) Single-use plastic pipettes. —Graduated, 2-mL, 10-mL and 25-mL. (k) Single-use syringes. —2-mL. (l) Graphitized carbon SPE columns. —100 mg. (m) Membrane filter nylon. —0.2 µm, Ø 4.7 cm (Only when using PA1 column for HPAEC- PAD). B. Apparatus and Materials (a) Analytical balance. —Readability of 0.1 mg. (b) pH-meter. —Readability of 0.1 pH.