GB/T 22988-2008Determination of spiramycin, pirlimycin, oleandomycin, tilmicosin, erythromycin and tylosin residues in milk and milk powder - LC-MS-MS method (English PDF)

1 Scope

This standard specifies the HPLC-tandem mass spectrometry method for the determination of spiramycin, pirlimycin, oleandomycin, tilmicascin, erythromycin, tylosin residues in milk and milk powder.

This standard is applicable to the determination and confirmation of spiramycin, pirlimycin, oleandomycin, tilmicascin, erythromycin, tylosin residues in milk and milk powder.

The method detection limit of this standard is 1 µg/kg for milk and 8 µg/kg for milk powder.

2 Normative references

The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding corrections) or revisions are not applicable to this standard.

However, parties that reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version applies to this standard.

GB/T 6379.1 Accuracy (trueness and precision) of measurement methods and results - Part 1: General principles and definitions (GB/T 6379.1-2004, ISO 5725-1:1994, IDT)

GB/T 6379.2 Measurement methods and results - Accuracy (trueness and precision)

- Part 2: Determine the standard methods of measurement repeatability and reproducibility of the basic method (GB/T 6379.2-2004, ISO 5725-2:1994, IDT)

GB/T 6682 Water for analytical laboratory use - Specification and test methods (GB/T 6682-2008, ISO 3696:1987, MOD)

3 Principle

The analytes in the specimen are extracted with acetonitrile, cleaned up with solid phase extraction column, determined by high performance liquid chromatography-tandem mass spectrometry, quantified by external standard method.

4 Reagents and materials

Unless otherwise specified, all reagents used are analytical grade; the water is grade 1 water as specified in GB/T 6682.

4.1 Acetonitrile, HPLC grade.

4.2 Methanol, HPLC grade.

4.3 Acetic acid, HPLC grade.

4.4 Ammonium formate, HPLC grade.

4.5 Disodium hydrogen phosphate.

4.6 Sodium hydroxide.

4.7 Methanol-water solution (3 + 7): 300 mL of methanol mixed with 700 mL of water.

4.9 0.1 mol/L phosphate buffer solution: Dissolve 6 g of disodium hydrogen phosphate (4.5) in 450 mL of water; use sodium hydroxide (4.8) solution to adjust pH to 8; add water to 500 mL; prepare it before use.

4.10 0.1 mol/L ammonium formate solution: Add water to dissolve 0.63 g of ammonium formate (4.4) to 1000 mL.

4.11 Standard products: Spiramycin (CAS: 8025-81-8), pirlimycin (CAS: 79548-73-5), oleandomycin (CAS: 7060-74-4), tilmicosin (CAS: 108050-54-0), erythromycin (CAS: 114-07-8), tylosin (CAS: 1401-69-0), purity greater than or equal to 98%.

4.12 Standard stock solution: Accurately weigh appropriate amount of standard products; use methanol to prepare 100 µg/mL standard stock solution.

4.13 Mixed standard intermediate working solution: Take 1 mL of each standard stock solution (4.12) into a 100 mL volumetric flask; use methanol to dilute to the mark; prepare a mixed standard working solution which has a concentration of 1 µg/mL. 10 mL of acetonitrile to repeat extraction once. Combine the supernatant in the same chicken heart bottle.

4.85 mol/L sodium hydroxide solution: Weigh 20 g of sodium hydroxide; dissolve it in water; dilute it to 100 mL.

7 Determination steps

8 Result calculation

The residual amount of analyte in the specimen is calculated using the data processing system or according to formula (1):

Where:

Xi - The residual amount of the measured component in the specimen, in micrograms per kilogram (µg/kg); ci - The concentration of the measured component solution obtained from the standard working curve, in nanograms per milliliter (ng/mL);

Vi - The final volume of the sample solution, in milliliters (mL); mi - The amount of the final sample represented by the sample solution, in grams (g). The blank value shall be deducted from the calculation result. […]

9 Precision