Determination of Aflatoxin M1 in Milk and Dairy Products

The determination of aflatoxin M1 in milk and dairy products includes immunoaffinity chromatography purification liquid chromatography-tandem mass spectrometry, immunoaffinity chromatography purification high performance liquid chromatography, immunochromatography purification fluorescence spectrophotometry and dual-flow enzyme Four national standard methods including combined immunization method
.

1.
Principle

The sample liquid or solid sample extract is homogenized, ultrasonically extracted, and centrifuged.
The supernatant is taken and purified by an immunoaffinity column.
The eluent is blown dry with nitrogen, constant volume, filtered by a microporous membrane, and subjected to liquid chromatography.
Separation, ionization by electrospray ion source, multiple reactive ion monitoring (MRM) detection
.

Where x- the content of aflatoxin M1 in the sample , ug/kg

p—— The concentration of aflatoxin M1 in the sample , ng/mL

V——Constant volume of sample, mL

f——Sample dilution factor

m—the weighing amount of the sample, g

2.

(1) Reference conditions for liquid chromatography

Mobile phase: solution A, 0.
1% formic acid solution; solution B, acetonitrile - methanol solution (1+1); gradient elution: see Table 6-5; mobile phase flow rate: 0.
3mL/min; column temperature: 35°C; Test solution temperature: 20℃; sample volume: 10uL
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Table 6-5 Liquid chromatography gradient elution conditions

Note: 1 means instant change, 6 means linear change
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(2) Reference conditions for mass spectrometry

Detection method: Multi-ion reaction monitoring (MRM), see the parent ion, product ion and collision energy in Table 6-6 for details
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Table 6-6 Ion selection parameter table

Table 6-7 Ion source control conditions

Figure 6-10 The product ion scan of aflatoxin M

The chromatographic mass spectrum of aflatoxin M1 is shown in Figure 6-11
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Figure 6-11 Chromatographic mass spectrum of aflatoxin M1

3.

(1) This law corresponds to ISO14501:2007 Milk and milk powder-determination of afla-toxin M, content-clean-up by immunoaffinity chromatography and determination by high-performance liquid chromatography
.

(2) In addition to this law, "GB5009.

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