AOAC OMB Final Action Recommendation (December 2019)-2016.14

2016.14 (October 2019) – FOS-03 MANUSCRIPT

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gradient described in Table 2016.14D . Carbohydrates are detected by pulsed amperometry using a 1 gold working electrode and an Ag/AgCl reference electrode, and an appropriate waveform for the 2 detection of carbohydrates. An example of a suitable waveform is given in Table 2016.14E . 3 Table 2016.14D. HPAEC-PAD gradient for CarboPac PA20 analytical column (or 4 equivalent) 5

Flow rate, mL/min

600 mM NaOH, % A

Water, % B

30 mM NaOH, % C

Time, min

0.0

0.5 0.5 0.5 0.5 0.5 0.5

0 0

80 80

20 20

17.0 17.1 27.0 27.1 33.0

100 100

0 0

0 0

0 0

80 80

20 20

6 Table 2016.14E. Example of quadruple waveform for carbohydrate detection 7 Time, s Voltage, V Gain region 0.00 + 0.10 Off 0.20 + 0.10 On 0.40 + 0.10 Off 0.41 - 2.00 Off 0.42 - 2.00 Off 0.43 + 0.60 Off 0.44 - 0.10 Off 0.50 -0.10 Off 8 J. Chromatographic Conditions (Using PA1) 9 If using a CarboPac PA20 column (or equivalent), skip this section. 10 The HPAEC-PAD system is equipped with the CarboPac PA1 guard (2 x 50 mm, 10 µm) and 11 analytical (2 × 250 mm, 10 µm) columns or equivalent, connected in series. The columns are held 12

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