GB/T 22262-2025Determination of clopidol in feeds (English PDF)

1 Scope

GB/T 22262-2025 is the Chinese national standard on determination of clopidol in feeds, in the field of agriculture. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 1 August 2025 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 February 2026. Classification: ICS 65.120, CCS B46. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This document describes methods for the determination of clopidol in feeds using high- performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). This document is applicable to the determination of clopidol in compound feeds, concentrate feeds, protein supplements, premixes, mixed feed additives, and animal- derived feed ingredients. In this document, the detection limit for high-performance liquid chromatography is

0.5 mg/kg, and the quantification limit is 1 mg/kg. The detection limit for liquid chromatography-tandem mass spectrometry is

0.05 mg/kg, and the quantification limit is

0.1 mg/kg.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 6682, Water for analytical laboratory use -- Specification and test methods

GB/T 20195, Animal feed -- Preparation of test samples

3 Terms and definitions

This document contains no terms or definitions requiring definition.

4 High-performance liquid chromatography

4.1 Principle Clopidol in the specimen is extracted using an ammonia-methanol solution. It is then purified using an alkaline alumina solid-phase extraction column. Determination is performed using high-performance liquid chromatography, and quantification is carried out using the external standard method.

4.2 Reagents or materials WARNING. The organic reagents used in this test are irritating to the upper respiratory tract. For safety, appropriate protective measures must be taken, and operations shall be conducted within a fume hood. Unless otherwise specified, only analytically pure reagents shall be used.

4.2.1 Water. GB/T 6682, Grade 1.

4.2.2 Methanol. chromatographically pure.

4.2.3 n-Hexane. 4.2.4 0.2% ammonia solution in methanol. accurately transfer 2 mL of ammonia solution. Dilute to 1000 mL with methanol. Mix thoroughly.

4.2.5 Methanol solution. measure 70 mL of methanol (4.2.2) and 30 mL of water, and mix thoroughly.

4.2.6 Standard stock solution (200 µg/mL). accurately weigh 10 mg (weighed to the nearest

0.01 mg) of the clopidol standard (CAS No.. 2971-90-6; purity >= 98%) into a 50 mL amber volumetric flask. Dissolve using methanol (4.2.2) with sonication, dilute to the set volume, and mix thoroughly. Store at temperatures below -18°C. The shelf life is 6 months. Alternatively, a certified standard solution may be purchased.

4.2.7 Standard series solutions. accurately transfer appropriate volumes of the standard stock solution (4.2.6). Dilute to the set volume using the methanol solution (4.2.5) and mix thoroughly. Prepare a series of standard solutions with mass concentrations of 0.2 µg/mL, 0.5 µg/mL, 2 µg/mL, 5 µg/mL, 20 µg/mL, 50 µg/mL, and 100 µg/mL. Prepare when needed.

4.2.8 Basic alumina solid-phase extraction column. 10 g/20 mL, or equivalent.

4.2.9 Microporous filter membrane. 0.45 µm, organic-based.