GB/T 40189-2021Determination of metronidazole and norfloxacin in toothpaste—High performance liquid chromatography method (English PDF)
牙膏中甲硝唑和诺氟沙星的测定 高效液相色谱法
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Issued by
SAMR; SAC
Level / Type
National · Recommended
Issue date
May 21, 2021
Implementation date
December 1, 2021
Scope
GB/T 40189-2021 is the English-translated version of 牙膏中甲硝唑和诺氟沙星的测定 高效液相色谱法.
GB/T 40189-2021 is the Chinese national method for detecting and measuring two banned antibiotic drugs, metronidazole and norfloxacin, in toothpaste by high performance liquid chromatography with ultraviolet detection.
The sample is extracted with a formic acid and acetonitrile solution, filtered through a 0.45 µm membrane and analysed on a C18 column at 290 nm; compounds are identified by retention time and quantified by the external standard peak area method, with a method detection limit of 1 mg/kg.
The document covers reagents and standard materials, instruments, specimen preparation, the chromatographic conditions, calibration, the blank test, result calculation, precision and the identification of positive samples.
Annex A gives a chromatogram of the mixed standard. Cosmetics testing laboratories use it. It was issued on 21 May 2021 and has applied since 1 December 2021.
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Document preview — GB/T 40189-2021
National Standard of the People's Republic of China
- ICS
- 71.040.40
- Classification
- Y 43
Issued by: State Administration for Market Regulation; Standardization Administration of the PRC
Contents
- Foreword3
- 1 Scope4
- 2 Normative references4
- 3 Principle4
- 4 Reagents and standard materials4
- 5 Instruments5
- 6 Specimen preparation5
- 7 Determination by high performance liquid chromatography6
- 8 Result calculation7
- 9 Precision7
- 10 Identification of positive samples7
- Annex A (informative) Liquid chromatogram of metronidazole and norfloxacin mixed standard sample8
1 Scope
This Standard specifies high performance liquid chromatography (HPLC) method for the content of forbidden antibiotic drugs - metronidazole and norfloxacin - in toothpaste.
This Standard is applicable to the determination of the content of forbidden antibiotic drugs - metronidazole and norfloxacin - in toothpaste. The method detection limit of this Standard is 1mg/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 6682-2008, Water for analytical laboratory use - Specification and test methods
3 Principle
The sample is extracted by the extraction solution. The supernatant is filtered through a 0.45µm filter membrane. Use high performance liquid chromatography-ultraviolet detection method to determine. Use retention time to characterize. Use external standard peak area method to quantify.
4 Reagents and standard materials
Unless otherwise specified, all reagents used are analytically-pure AND water is grade one water specified in GB/T 6682-2008.
4.1 Extraction solution: 0.1% (volume fraction) formic acid aqueous solution: acetonitrile (95:5, volume ratio).
7 Determination by high performance liquid chromatography
7.1 Reference conditions of liquid chromatography
The reference conditions of liquid chromatography are as follows:
a) Chromatographic column: C18 stainless steel column (250mm×4.6mm×5µm).
b) Detection wavelength: 290nm.
c) Mobile phase: use triethylamine to adjust the pH value of 0.1% (volume fraction) phosphoric acid aqueous solution: acetonitrile (83:17, volume ratio) to 2.5~3.0.
d) Flow rate: 1.0mL/min.
e) Column temperature: 30°C.
f) Injection volume: 10µL.
7.2 Preparation of standard working solution
Use mobile phase solution to gradually dilute 100mg/L mixed standard stock solution (4.7). Prepare into 50mg/L, 20mg/L, 10mg/L, 5mg/L standard working solutions. Use 0.45µm filter membrane to filter for future use. Under the set chromatographic conditions, respectively take 10µL for analysis. Take the mass concentration of the standard series of solutions as the abscissa (mg/L), the peak area of the reference substance as the ordinate to draw the calibration curve (linear correlation coefficient R >=0.9990). Refer to Figure A.1 in Annex A for the liquid chromatogram of metronidazole and norfloxacin mixed standard sample.
7.3 Determination steps
After the sample is processed according to the steps in Chapter 6, perform on-board testing according to the instrument conditions of 7.1. The response values of metronidazole and norfloxacin in the test sample solution shall be within the linear range of the standard curve. If it exceeds the linear range, it shall be diluted before injection for determination.
7.4 Blank test
Except for not adding specimen, the test is carried out according to the processing steps in Chapter 6 and the instrument conditions in 7.1. […]
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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 15 pages — is available in the English PDF.
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