GB 5009.270-2023National food safety standard - Determination of inositol in foods (English PDF)

3.1 Reagents

3.1.1 Absolute ethanol (C2H6O).

3.2 Preparation of Reagents

3.2.1 70% ethanol. measure-take 700 mL of absolute ethanol, use water to reach a constant

volume of 1,000 mL, and evenly mix it.

3.2.2 Silanization reagent. respectively draw-take trimethylchlorosilane,

hexamethyldisilazane and N, N-dimethylformamide, mix them in a volume ratio of 1.2.8,

and conduct ultrasonic mixing. Prepare it right before use.

3.3 Reference Material

Inositol reference material (C6H12O6, CAS. 87-89-8). purity  99%, or a standard substance

certified by the state and awarded a reference material certificate.

3.4 Preparation of Standard Solutions

4.1 Gas chromatograph. equipped with a hydrogen flame ionization detector.

4.2 Analytical balance. with a division value of 0.1 mg and 1 mg.

4.5 Constant-temperature water bath. with a temperature accuracy of  2 C.

4.6 Rotary evaporator.

4.7 Vortex oscillator.

4.8 Ultrasonoscope.

4.9 Nitrogen blower.

5.1 Specimen Preparation

5.3 Reference Conditions of Instrument

The reference conditions of the instrument are as follows.

5.4 Drawing of Standard Curve

Respectively inject the inositol standard determination solutions into the gas chromatograph,

take the mass of inositol in the inositol standard determination solutions as the x-coordinate

and the measured peak area as the y-coordinate to draw a standard curve.

5.5 Determination of Specimen Solution

Inject the specimen determination solution into the gas chromatograph to measure the

retention time and peak area.

10.1 Equipment

10.1.1 Balance. with a division value of 0.1 mg, 1 mg and 0.1 g.

10.1.10 Vortex oscillator.

10.1.11 Homogenizer.

10.2 Materials

10.2.1 Glass beads. with a diameter of about 5 mm.

10.2.3 Sterile pipette. 10 mL (with a scale of 0.1 mL) or 10 mL micropipette and tip.

10.2.4 Conical flask. 200 mL or 250 mL.

10.2.5 Volumetric flask (Type A). 50 mL, 100 mL and 250 mL.

10.2.6 Funnel. with a diameter of 90 mm.

11.1 Culture Media

11.2 Reagents and Strain

11.2.1 Sodium chloride (NaCl).

11.2.2 Sodium hydroxide (NaOH).

11.2.3 Hydrochloric acid (HCl).

11.3 Preparation of Reagents

11.5 Preparation of Standard Solutions

12.1 Preparation of Strain

12.2 Preparation and Extraction of Specimens

Solid specimens, for example, cereals, need to be crushed, ground and sieved (the sieve plate

has an aperture of 0.3 mm ~ 0.5 mm); for specimens such as meat and meat products, use a

homogenizer to make them into chyme; specimens such as fruits and vegetables need to be

homogenized and evenly mixed; for liquid specimens, shake and mix them before

determination. Specimens are prepared right before use.

12.3 Preparation of Standard Solution

In accordance with Table 2, respectively add water, inositol standard working solution and

inositol determination culture medium into the culture tubes. Prepare 3 portions of each tube

in parallel.

12.4 Preparation of Test Solution

In accordance with Table 3, respectively add water, specimen extracting solution and inositol

determination culture medium into the culture tubes. Prepare 3 portions of each tube in

parallel.

......