GB/T 22338-2008 PDF English
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| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GB/T 22338-2008 | English | 105 |
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Determination of multi-residues of chloramphenicol in animal-original food
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GB/T 22338-2008: Determination of multi-residues of chloramphenicol in animal-original food---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT22338-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.120
X 22
Determination of multi-residues of chloramphenicol in
animal-original food
Issued on. SEPTEMBER 01, 2008
Implemented on. DECEMBER 01, 2008
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 3
1 Scope... 4
2 Gas chromatography-mass spectrometry... 4
3 Liquid chromatography-mass spectrometry/mass spectrometry... 9
Annex A (informative) Gas chromatography-mass spectrometry total ion current
chromatogram and mass spectrum of chloramphenicol derivatives... 16
Annex B (informative) Average recovery rate and precision of chloramphenicol in
different matrices (GC/MS method)... 17
Annex C (informative) Reference conditions for liquid chromatography-mass
spectrometry/mass spectrometry... 18
Annex D (informative) Liquid chromatography-mass spectrometry/mass spectrometry
total ion chromatogram and reconstructed ion chromatogram of chloramphenicol... 19
Annex E (informative) Average recovery rate and precision of chloramphenicol drugs
in different matrices (LC-MS/MS method)... 21
Foreword
Annex A, Annex B, Annex C, Annex D and Annex E of this Standard are all informative.
This document was proposed by General Administration of Quality Supervision,
Inspection and Quarantine of the People's Republic of China.
This document shall be under the jurisdiction of the National Certification and
Accreditation Administration Commission.
The drafting organizations of this document. China Academy of Inspection and
Quarantine, Shandong Entry-Exit Inspection and Quarantine Bureau of the People's
Republic of China.
Main drafters of this document. Qiu Yueming, Lin Liming, Li Peng, Zhang Hongwei,
Zhao Haixiang, Dong Yiyang, Cai Huixia, Xie Mengxia, Wang Liping, Kong Ying.
Determination of multi-residues of chloramphenicol in
animal-original food
1 Scope
This Standard specifies the methods of gas chromatography-mass spectrometry and
liquid chromatography-mass spectrometry/mass spectrometry to determine the multi-
residues of chloramphenicol in animal-original food.
This Standard is applicable to the qualitative confirmation and quantitative
determination of chloramphenicol, florfenicol and thiamphenicol residues in aquatic
products, livestock and poultry products and livestock and poultry by-products.
2 Gas chromatography-mass spectrometry
2.1 Principle
The sample is extracted by ethyl acetate. It is distributed and purified by 4% sodium
chloride solution and n-hexane solution. After purification by Florisil column, take
toluene as the reaction medium. Use N,O bis(trimethylsilyl)trifluoroacetamide-
trimethylchlorosilane (BSTFA+TMCS, 99+1) to silanize at 70°C. Use gas
chromatography/negative chemical ionization source mass spectrometry to determine.
Use internal standard working curve method for quantification.
2.2 Reagents and materials
Unless otherwise stated, it shall only use the confirmed analytically-pure reagents and
secondary deionized water or water of equivalent purity in the analysis.
2.2.1 Methanol. Chromatographically pure.
2.2.2 Toluene. Pesticide residue level.
2.2.3 N-hexane. Pesticide residue level.
2.2.4 Ethyl acetate.
2.2.5 Ether.
2.2.6 Sodium chloride.
2.2.13 Derivatization reagent. N, O bis (trimethylsilyl) trifluoroacetamide-
trimethylchlorosilane (BSTFA+TMCS, 99+1).
2.2.14 Solid phase extraction column. Florisil column (6.0mL, 1.0g).
2.3 Instruments and equipment
2.3.1 Gas chromatography/mass spectrometer. equipped with chemical ionization
source (CI).
2.3.2 Tissue masher.
2.3.3 Solid phase extraction device.
2.3.4 Oscillator.
2.3.5 Rotary evaporator.
2.3.6 Vortex mixer.
2.3.7 Centrifuge.
2.3.8 Incubator.
2.4 Determination steps
2.4.1 Extraction
Weigh 10g (accurate to 0.01g) of the crushed tissue sample into a 50mL stoppered
centrifuge tube. Add 1.0mL of internal standard solution (2.2.11) and 30mL of ethyl
acetate. Shake for 30min. Centrifuge at 4000r/min for 2min. Transfer the supernatant
to a round bottom flask. Use 30mL of ethyl acetate to extract the residue one more time.
Combine the extracts. Conduct rotary evaporation at 35 ℃ to 1mL ~ 2mL, for
purification.
2.4.2 Purification
2.4.4 Determination
2.4.4.1 Gas chromatography-mass spectrometry conditions
2.4.4.4 Quantitation
Use m/z466 (m-CAP and CAP), 339 (FF) and 409 (TAP) as quantitative ions. The
response values of chloramphenicol derivatives in the sample solution shall be within
the linear range determined by the instrument. Under the above chromatographic
conditions (2.4.4.1), the reference retention time of m-CAP, CAP, FF, TAP standard
substance derivatives is about 11.4min, 11.8min, 12.6min, 13.6min. For the total ion
chromatogram and mass spectrum of chloramphenicol derivatives, see Figure A.1,
Figure A.2 in Annex A.
2.4.5 Parallel experiment
According to the above steps, carry out parallel test determination on the same specimen.
2.4.6 Blank experiment
Carry out according to the above-mentioned determination steps except that no
specimen is added.
2.5 Result calculation
The result is calculated according to formula (1).
3 Liquid chromatography-mass spectrometry/mass spectrometry
3.1 Principle
For residues of chloramphenicol, thiamphenicol and florfenicol in different animal-
original food, use acetonitrile, ethyl acetate-ether or ethyl acetate to respectively extract.
The extract is purified with a solid phase extraction cartridge.
3.2 Reagents and materials
Unless otherwise stated, it shall only use the confirmed analytically-pure reagents and
secondary deionized water or water of equivalent purity in the analysis.
3.2.1 Methanol. liquid chromatography level.
3.2.8 Sodium acetate.
3.2.9 Ammonium acetate.
3.2.10 β-glucuronidase. about 40,000 activity units.
3.2.11 Acetonitrile saturated n-hexane. Take 200mL of n-hexane (3.2.5) into a 250mL
separatory funnel. Add a small amount of acetonitrile (3.2.2). Shake vigorously. After
standing for stratification, discard the lower acetonitrile layer.
3.2.12 Acetone-n-hexane (1+9). Mix acetone (3.2.3) and n-hexane (3.2.5) well in a
volume ratio of 1.9.
3.2.19 Standard stock solution. Accurately and respectively weigh an appropriate
amount of chloramphenicol, thiamphenicol and florfenicol standard substances (3.2.17)
(accurate to 0.1mg). Use acetonitrile to prepare 500μg/mL standard stock solution (it
can be used for 6 months when stored in the dark at 4°C).
3.2.25 LC-Si solid phase extraction cartridge or equivalent. 200mg, 3mL.
3.2.26 EN solid phase extraction cartridge or equivalent. 200mg, 3mL.
3.2.27 Disposable syringe filter. equipped with 0.45μm microporous membrane.
3.3 Instruments and equipment
3.3.1 Liquid chromatography-tandem mass spectrometer. equipped with electrospray
ionization source.
3.3.2 High-speed tissue masher.
3.3.3 Homogenizer.
3.3.4 Rotary evaporator.
3.3.5 Analytical balance.
3.3.6 Pipette gun. 200μL, 1mL.
3.3.7 Heart-shaped bottle. 100mL, brown.
3.3.8 Separation funnel. 200mL.
3.3.9 Teflon centrifuge tube. 50mL.
3.3.10 Centrifuge.
3.4.2 Specimen storage
The specimen shall be stored at -20°C.
3.5 Determination steps
3.5.1 Extraction
3.5.3.4 Quantitative determination
Chloramphenicol is quantified by the internal standard method. Thiamphenicol and
florfenicol are quantified by the external standard method.
3.6 Result calculation
The residual amount of the target compound in the specimen is calculated according to
the formula (2) using the instrument data processing system or the residual amount of
chloramphenicol. Thiamphenicol and florfenicol are calculated according to formula
(3).
3.7 Lower limit of determination
The lower limit of determination of chloramphenicol by liquid chromatography-mass
spectrometry/mass spectrometry is 0.1μg/kg. It is 0.1μg/kg for thiamphenicol and
florfenicol.
3.8 Recovery rate and precision
See Annex E.
Annex A
(informative)
Gas chromatography-mass spectrometry total ion current chromatogram and
mass spectrum of chloramphenicol derivatives
Annex B
(informative)
Average recovery rate and precision of chloramphenicol in different matrices
(GC/MS method)
Annex C
(informative)
Reference conditions for liquid chromatography-mass spectrometry/mass
spectrometry 1
Reference conditions for liquid chromatography-mass spectrometry/mass spectrometry
Annex E
(informative)
Average recovery rate and precision of chloramphenicol drugs in different
matrices (LC-MS/MS method)
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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