AOAC OMB Final Action Recommendation (December 2019)-2016.14
2016.14 (October 2019) – FOS-03 METHOD
FOR ERP USE ONLY DO NOT DISTRIBUTE
0.2 – 4.0 2.5 – 45 25 – 100
0.03 – 0.45
No dilution
No dilution
1
0.3 – 4.5 3.0 – 45
5
50 50
10
0.5
100
234
(e) Hydrolysis of sucrose and α-glucans.— Transfer 200 µL Solution B H(d) into a 1.5-mL microtube,
235
add 100 µL of N,N’ -diacetylchitobiose internal standard solution D(d) and 200 µL sucrase/ β -
236
amylase/pullulanase/maltase enzyme mixture D(j) . Mix well (vortex), place the microtubes on a
237
floating rack and incubate at 40 °C for 90 min. Cool down to room temperature. NOTE: Adapt
238
these conditions (time and temperature) according to enzyme manufacturer recommendations.
239
(f) Optional Carrez Clarification .—(Use in case of difficulties passing sample through SPE.) Add
240
10 µL Carrez I solution D(g) to the sample and mix well. Then add 10 µL Carrez II solution D(h)
241
and mix again. Centrifuge at 10 000 x g for 10 min and use the supernatant for the next step H(g) .
242
(g) Removal of monosaccharides.— Prepare the graphitized carbon SPE columns B(l) , as follows (try
243
to avoid passing air through the SPE column before the final elution step (g) as this may result in
244
higher blank measurements):
245
a. Flush with 3 × 400 µL SPE wash solution D(l) .
246
b. Flush with 3 × 400 µL water.
247
248
Then perform the following steps under gravity if possible, or up to an elution flow rate
249
of 2 mL/min with positive pressure:
c. Apply 400 µL of the enzyme treated solution H(e) or H(f) .
250
d. Wash with 2 × 1 mL NaCl solution D(m) .
251
e. Wash with 4 × 1 mL water.
252
f. Elute the fructans into a 2-mL microtube using 4 × 400 µL SPE elute solution D(m) .
253
g. Apply a little positive pressure to eliminate all solution from the column.
254
h. Mix eluates from the SPE column well (vortex).
255
12
Made with FlippingBook HTML5