1 Scope
The standard specifies the determination of cefapirin, cephalexin, cefalonium, cefquinome residues in milk and milk powder—LC-MS-MS method.
The standard is applicable to the determination of cefapirin, cephalexin, cefalonium, cefquinome residues in milk and milk powder.
The method detection limit of milk of this standard: 4.0μg/kg for cefapirin, cephalexin, cefalonium and cefquinome; the method detection limit of milk powder of this standard: 32μg/kg for cefapirin, cephalexin, cefalonium, cefquinome.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply to this standard. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition applies.
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 Accuracy (trueness and precision) of measurement methods and results—Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement 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 residues of the four cephalosporins in the specimen are first extracted with acetonitrile and phosphate buffer solution and purified with a solid phase extraction column, and then determined by liquid chromatograph mass spectrometer, and quantified by external standard method.
Foreword i
1 Scope
2 Normative references
3 Principle
4 Reagents and materials
5 Apparatuses
6 Specimen preparation and preservation
7 Determination procedures
8 Result calculation
9 Precision
Annex A (Informative) Multi reaction monitoring (MRM) chromatograms of reference materials
Annex B (Informative) Recovery rate
