GB 31604.13-2016National food safety standard - Food contact materials and products - Determination of 11- amino undecanoic acid migration quantity (English PDF)

3.1 Reagents

3.1.1 Disodium tetraborate decahydrate (Na2B4O7·10H2O).

3.1.2 Phosphoric acid (H3PO4).

3.1.3 Boric acid (H3BO3).

3.1.4 Fluorescent amine (C17H10O4).

3.1.5 Sodium hydroxide (NaOH).

11-amino undecanoic acid (C11H23O2N, CAS No.. 2432-99-7), purity >= 99%, or

standard substance which is identified by national authentication and awarded

a reference material certificate.

3.4 Standard solution preparation

3.4.1 11-amino undecanoic acid aqueous-solution stock solution (1.25mg/mL).

Accurately WEIGH 125mg (accurate to 0.1mg) of 11-amino undecanoic acid

standards; USE 2mL of 96% acetic acid to dissolve it; TRANSFER it into 100mL

volumetric flask; USE water to dilute it to the mark; STORE it in a refrigerator at

3.4.4 Water-based, acidic food, alcoholic food simulants standard working

solution. Respectively MOVE 0mL, 1.0mL, 2.0mL, 4.0mL, 10.0mL, 20.0mL of

11-amino undecanoic acid aqueous solution standard intermediate solution into

50mL volumetric flask; USE water to dilute it. The concentration of the standard

working solution is 0µg/mL, 0.5µg/mL, 1.0µg/mL, 2.0µg/mL, 5.0µg/mL and

10.0µg/mL, respectively. In the same way, USE the corresponding acidic and

alcoholic food simulants to prepare 11-amino undecanoic acid standard working

solution with the same concentration series. PREPARE it when in use.

3.4.5 Oil-based food simulant standard working solution. WEIGH 5g (accurate

to 0.01g) of olive oil respectively; PLACE it into 6 different 25mL conical flasks.

Respectively ADD 0µL, 5µL, 10µL, 20µL, 50µL and 100µL of 11-amino

undecanoic acid isooctane stock solution; MIX it uniformly. The concentration

of standard working solution is 0µg/g, 0.5µg/g, 1.0µg/g, 2.0µg/g, 5.0µg/g and

10.0µg/g, respectively. Then operate according to 5.2.2.

4.1 High performance liquid chromatography. Equipped with fluorescence

detector.

4.2 Oscillator. Reciprocating-type.

Accurately MOVE 1.0mL of boric acid buffer solution into the prepared water-

based, acidic, alcoholic, oil-based food simulant test solution and the prepared

blank solution; PLACE it on vortex oscillator for 10s; MIX it uniformly. During the

mixing process, ADD 1.0mL of fluorescamine solution. The resulting derivative

solution is passed through microfiltration membrane; the filtrate is waiting for

determination.

5.5 Instrument reference conditions

a) Chromatographic column. C18 column (column-length 250mm, inner-

diameter 4.6mm, particle-size 5µm), or the chromatographic column with

equivalent performance.

b) Mobile phase. methanol-phosphate buffer solution (70+30, volume ratio).

c) Flow rate. 1.0mL/min.

d) Injection volume. 10µL.

e) Column temperature. room temperature.

f) Fluorescence detector. excitation wavelength 390nm, emission

wavelength 480nm.

5.6 Drawing of standard working curve

Respectively PIPETTE the above standard series of derivatization solution into

liquid chromatograph; DETERMINE the corresponding peak area according to

5.5 instrument reference conditions (see Appendix A for the chromatogram of

11-amino undecanoic acid standard substance derivative). With the 11-amino

undecanoic acid concentration of standard working solution as abscissa, AND

the corresponding peak area of 11-amino undecanoic acid as vertical axis,

DRAW a standard working curve.

5.7 Determination of sample solution

According to 5.5 instrument reference conditions, INJECT the sample derivative

solution into liquid chromatograph; DETERMINE the nature based on the

retention time; at the same time, RECORD peak area; OBTAIN the

concentration of 11-amino undecanoic acid in the solution-under-test according

to the standard curve.