AOAC OMB Final Action Recommendation (December 2019)-2016.14

2016.14 (October 2019) – FOS-03 METHOD

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17.0

0.5

0

80

20

17.1

0.5

100

0

0

27.0

0.5

100

0

0

27.1

0.5

0

80

20

33.0

0.5

0

80

20

276 Table 2016.14E. Example of quadruple waveform for carbohydrate detection 277

Time, s

Voltage, V

Gain region

0.00 0.20 0.40 0.41 0.42 0.43 0.44 0.50

+ 0.10 + 0.10 + 0.10 - 2.00 - 2.00 + 0.60 - 0.10 -0.10

Off On Off Off Off Off Off Off

278

J.

Chromatographic Conditions (Using PA1)

279

280

If using a CarboPac PA20 column (or equivalent), skip this section.

The HPAEC-PAD system is equipped with the CarboPac PA1 guard (2 x 50 mm, 10 µm) and analytical 281

(2 × 250 mm, 10 µm) columns or equivalent, connected in series. The columns are held at 20 °C and the 282

injection volume is 20 µL. NaOH (300 mM) is added post-column (before the PAD detector) at a flow rate 283

of 0.13 mL/min, using a T-piece and a 125-µL reaction coil (or equivalent). Fructose and glucose are 284 separated using the gradient described in Table 2016.14F . Carbohydrates are detected by pulsed 285 amperometry using a gold working electrode and an Ag/AgCl reference electrode, and an appropriate 286

14