AOAC RI ERP E-Book - DS DF

OMAMAN-38 B: Collaborative Study Protocol Expert Review Panel Use Only September, 2017

shaking action/sample agitation in water bath is sufficient to maintain sample solids in suspension and that no residue buildup or rings of sample material form in the digestion bottle during the enzymatic digestions (i.e. at 150 rev/min) (Figure 2017.xxB). If the water bath is used in linear motion (not preferred motion), then the bottles must be placed at an angle of 45 o to the direction of movement to ensure continual suspension of the sample during the 4 h incubation period with PAA/AMG. Alternatively, mixing can be achieved with a 2mag Mixdrive 15 ® submersible magnetic stirrer https://www.2mag.de/en/products/mehrstellenruehrer-e/mit-externer- steuerung-2/mixdrive-15-e.html with a 30 × 7 mm stirrer bar, set at 170 rpm (Figure 2017.xxC).

(h) (i) (j) (k)

Balance .— 0.1 mg readability, accuracy, and precision .

Ovens .— two, mechanical convection, set at 103 ± 2°C and 130 ± 3°C.

Timer.

Desiccator .— airtight, with SiO 2 or equivalent desiccant. Desiccant dried biweekly overnight in 130 °C oven, or more frequently as needed.

(l)

pH meter.

Pipettors and tips.— 50-200 µL and 5 mL capacity.

(m)

(n)

Dispensers.—

i. 15 ± 0.5 mL for 78 % EtOH (or IMS), 95 % ethanol (or IMS), and acetone. ii. 35 ± 0.5 mL for buffer.

(o) (p) (q) (r) (s) High Performance Liquid chromatograph (HPLC).— With oven to maintain a column temperature of 80°C and a 50 µL injection loop. Column operating conditions are: Temperature, 80°C; mobile phase, distilled water, flow rate, 0.5 mL/min. AOAC Research Institute ERP Use Only Cylinder , graduated, 100 mL and 500 mL. Magnetic stirrers and stirring bars. Rubber spatulas Muffle furnace .— 525 ± 5°C Polypropylene tube; 40 mL, 84 x 30 mm, flat base with screw cap; 13 mL, 101 x 16.5 mm, flat base, with screw cap. (t)

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