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GB 5413.37-2010 English PDF

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GB 5413.37-2010: National food safety standard -- Determination of aflatoxin M1 in milk and milk products
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Basic data

Standard ID GB 5413.37-2010 (GB5413.37-2010)
Description (Translated English) National food safety standard -- Determination of aflatoxin M1 in milk and milk products
Sector / Industry National Standard
Classification of Chinese Standard C53;X16
Classification of International Standard 67.100.10
Word Count Estimation 17,150
Date of Issue 2010-03-26
Date of Implementation 2010-06-01
Older Standard (superseded by this standard) GB/T 18980-2003
Quoted Standard GB/T 6682
Adopted Standard ISO 14501-2007, NEQ
Regulation (derived from) Circular of the Ministry of Health (2010)7
Issuing agency(ies) Ministry of Health of the People's Republic of China
Summary This Chinese standard specifies the milk and milk products Determination of aflatoxin M1. The first method is applicable to this standard milk and milk products Determination of aflatoxin M1, second law applies to milk, milk powder, as well as low-fat milk, skim milk, low-fat milk and skim milk powder aflatoxin M1 Determination, Third Law applies to milk and milk aflatoxin M1 side fixed, fourth method is applicable to liquid milk and milk powder Determination of aflatoxin M1.

GB 5413.37-2010: National food safety standard -- Determination of aflatoxin M1 in milk and milk products


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National food safety standard.Determination of aflatoxin M1 in milk and milk products National Standards of People's Republic of China People's Republic of China Ministry of Health issued Issued on. 2010-03-26 2010-06-01 implementation National Food Safety Standard Determination of aflatoxin M1 aflatoxin in milk and milk products National food safety standard Determination of aflatoxin M1 in milk and milk products

Foreword

The first method corresponds to the standard ISO 14501.2007 Milk and milk powder-determination of aflatoxin M1 content -clean-up by immunoaffinity chromatography and determination by high-performance liquid chromatography, This standard is the first method and the ISO 14501.2007 is not equivalent degree of consistency; instead of GB/T 18980-2003 Standard Method II and III of this Act; The fourth standard method from NY/T 1664-2008 "milk aflatoxin M1 rapid detection of double-flow ELISA." The Standard Appendix A and Appendix B is an informative annex. National Food Safety Standard Determination of aflatoxin M1 aflatoxin in milk and milk products

1 Scope

This standard specifies the method for determination of milk and milk aflatoxin M1. The first method is suitable for standard milk and dairy products Determination of aflatoxin M1; the second law applies to milk, milk powder, as well as low-fat milk, de Fat milk, low-fat milk aflatoxin M1 determination of skimmed milk powder and aflatoxin; third method is applicable to milk and milk powder Determination of aflatoxin M1 in; The fourth method is suitable for liquid milk and milk powder Determination of aflatoxin M1.

2 Normative references

The standard file referenced in the application of this standard is essential. For dated references, only the edition date of the note Apply to this standard. For undated references, the latest edition (including any amendments) applies to this standard. The first method immunoaffinity chromatography purification liquid chromatography - tandem mass spectrometry Principle 3 The sample liquid or solid sample extract was homogenized, ultrasonic extraction, centrifugation, the supernatant was purified by immunoaffinity column, eluted with nitrogen Dry, constant volume, microporous membrane filtration, separation by liquid chromatography electrospray ionization ion source, multiple reaction monitoring (MRM) mode Testing. Matrix spiked external standard.

4 Reagents and materials

Unless otherwise specified, the reagents used in this method are analytically pure water GB/T 6682 provided a water. 4.1 formic acid (HCOOH). 4.2 acetonitrile (CH3CN). chromatography. 4.3 petroleum ether (CnH2n 2). boiling range of 30 ℃ ~ 60 ℃. 4.4 chloroform (CHCl3). 4.5 Nitrogen. purity ≥99.9%. 4.6 aflatoxin M1 standard sample. purity ≥98%. 4.7 acetonitrile - water (14). In 400 mL of water was added 100 mL acetonitrile. 4.8 acetonitrile - water (19). In 450 mL of water was added 50 mL acetonitrile. 4.9 0.1% formic acid aqueous solution. draw 1 mL formic acid (4.1), diluted with water to 1000 mL. 4.10 acetonitrile - methanol solution (5050). Add 500 mL of methanol in 500 mL of acetonitrile. 4.11 Sodium hydroxide solution (0.5 mol/L). Weigh 2 g of sodium hydroxide dissolved a 100 mL of water. 4.12 blank matrix solution Weigh the sample matrix and the same, excluding the measured aflatoxin negative sample 8 parts in 100 mL beaker. Following 6.1 test solution by extraction and purification steps 6.2. The combined sample obtained 8 parts of purified liquid, with a 0.22 μm microporous membrane disposable filter head (5.23) and filtered. Discard the first 0.5 mL filtrate, then take a small amount of filtrate for liquid chromatography - mass spectrometry detection. Get chromatography - mass spectrum after control Appendix A in Figure A.2, the appropriate retention time, should be free of aflatoxin M1. Surplus It filtrate was transferred to a brown bottle and kept in the refrigerator -20 ℃, for the preparation of standard solution series use. 4.13 aflatoxin M1 standard stock solution. Weigh standard aflatoxin M1 0.10 mg (accurate to 0.01 mg), trichloroacetic Methane (4.4) to dissolve the volume to 10 mL. This standard solution at a concentration of 0.01 mg/mL. The solution was transferred to a brown glass bottle at -20 ℃ The refrigerator saved spare. 4.14 aflatoxin M1 standard solution series. lessons aflatoxin M1 standard stock solution (4.13) 10 μL to 10 mL volumetric flask, Chloroform blown with nitrogen to near dryness blank matrix solution (4.12) to volume, and the resulting concentration of 10 ng/M1 standard mL intermediate solution liquid. Then blank matrix solution (4.12) to aflatoxin M1 standard intermediate solution was diluted to 0.5 ng/mL, 0.8 ng/mL, 1.0 ng/mL, 2.0 ng/mL, 4.0 ng/mL, 6.0 ng/mL, 8.0 ng/mL series of standard working solution. 5. Apparatus 5.1 Liquid chromatography - mass spectrometry, ion source charged. 5.2 Column. ACQUITY UPLC HSS T31, column length 100 mm, column diameter 2.1 mm; particle size 1.8 μm, or equivalent of Energy column. 5.3 Balance. a sense of the amount of 0.001 g and 0.00001 g. 5.4 homogenizer. 5.5 ultrasonic cleaner. 5.6 Centrifuge. ≥6000 rpm rev/min. 5.7 50 mL centrifuge tube with a stopper PVC. 5.8 water bath. temperature 30 ℃ disabilities 2 ℃, 50 ℃ disabilities 2 ℃, the temperature range of 25 ℃ ~ 60 ℃. 5.9 volumetric flasks. 100 mL. 5.10 a glass beaker. 250 mL, 50 mL. Ground glass test tube with a scale of 5.11. 5 mL, 10 mL, 20 mL. 5.12 pipette. 1.0 mL, 2.0 mL and 50.0 mL. 5.13 a glass rod. 5.14 10 mesh sieve hole. 5.15 250 mL separatory funnel. 5.16 100 mL round bottom flask. 5.17 rotary evaporator. 1 This information is given for the convenience of users of this standard does not imply endorsement of the product, if other equivalent product has the same effect, you can use this These equivalent products. 5.18 pH meter. accuracy of 0.01. 5.19 250 mL stoppered Erlenmeyer flask. 5.20 immunoaffinity column. syringe 3 mL. 5.21 10 mL and 50 mL disposable syringes. 5.22 solid phase extraction device (with vacuum system). 5.23 disposable microporous filter head. with a 0.22 μm membrane filter (water-phase system). Step 6 Analysis 6.1 test solution extraction 6.1.1 Milk. Weigh 50 g (accurate to 0.01 g) mixed sample, placed in 50 mL centrifuge tube with a stopper (5.7) and heated in a water bath (5.8) in To 35 ℃ ~ 37 ℃. 6000 rev/min centrifuged for 15 min. All the supernatant was collected for purification. 6.1.2 fermented milk (including solid, semi-solid and with pulp type). Weigh 50 g (accurate to 0.01 g) mixing the sample with 0.5 mol/L of Sodium hydroxide solution (4.11) in pH meter (5.18) indicates lower pH to 7.4, at 9500 rev/min homogenates (5.4) 5 min, the following press 6.1.1 Operation. 6.1.3 milk powder and powdered infant formula. Weigh 10 g (accurate to 0.01 g) sample, placed in 250 mL beaker. The 50 mL was Preheated to 50 ℃ water is added to milk powder, mixing it with a glass rod. If the milk powder has not completely dissolved, the beaker was placed 50 ℃ Water bath (5.8) placed in 30 min. After cooling to dissolve 20 ℃, transferred to 100 mL volumetric flask, with a small amount of water washes the beaker, washed Be transferred to the liquid in the flask with water to volume, respectively, after shaking move two 50 mL centrifuge tubes (5.7), and 6000 rev/min Centrifugation 15 min, the supernatant was mixed with a pipette, taking supernatant for purification with 50mL. 6.1.4 Cheese. Weigh learn chopped, over a 10-mesh sieve and mix the sample hole 5g (accurate to 0.01 g), placed in a 50 mL centrifuge tube (5.7), add 2 mL of water and 30 mL of methanol at 9500 rev/min homogenized 5 min, ultrasonic extraction 30 min, 6000 r/min centrifugation 15 min. The supernatant was collected and transferred to a 250 mL separatory funnel. After addition of 30 mL of petroleum ether (4.3) in a separatory funnel, shaken for 2 min, to be layered, The underlying shift in the 50 mL beaker, discard petroleum ether layer. The extraction was repeated twice with petroleum ether. The lower layer solution was transferred to 100 mL round bottom flask, To about 2 mL of concentrated under reduced pressure, the concentrate was poured into a centrifuge tube, a flask with acetonitrile - water (1 4) (4.7) 5 mL 2 times wash, a washing liquid And poured into 50 mL centrifuge tube, diluted with water to approximately 50 mL, at 6000 rev/min, centrifuged for 5 min, the supernatant for purification. 6.1.5 Cream. Weigh 5g (accurate to 0.01 g) sample, placed in a 50 mL beaker with 20 mL of petroleum ether (4.3) which was dissolved and moved to 250mL conical flask with stopper. Add 20 mL of water and 30 mL of methanol, was shaken 30 min, all manner of liquid shift in the separatory funnel, to be layered, The lower layer solution move all 100 mL round bottom flask, rotary evaporator (5.17) and concentrated under reduced pressure to about 5 mL, diluted with water to about 50 mL, for purification. 6.2 Purification 6.2.1 prepare the immunoaffinity column The disposable 50 mL syringe barrel and affinity column (5.20) on top in series, then the affinity column with the solid phase extraction device connected. Note. Depending on immunoaffinity column using a specification requirements, control the pH test solution. 6.2.2 purified sample Will move above 6.1 test solution extract 50 mL syringe barrel (5.21), the adjustment means of solid phase extraction vacuum system, a control sample of 2 mL/min ~ 3 mL/min through the column at a flow rate stable. Remove the 50 mL syringe barrel, fitted with 10 mL syringe barrel. Plus syringe barrel Into the water to stabilize the flow rate of the column was washed and then drained affinity column. Disengage the vacuum system, and a lower affinity column into 10 mL graduated test tube, Upper loading another 10 mL syringe barrel, added 4 mL of acetonitrile (4.2), elution aflatoxin M1, the eluent was collected in graduated test tube In (5.11), elution time less than 60 seconds. Then slowly with nitrogen at 30 ℃ eluate was evaporated to near dryness (If evaporated to dryness, Lose aflatoxin M1), with acetonitrile - diluted to 1 mL aqueous solution (19). 6.3 Reference conditions Liquid Chromatography Mobile phase. A solution 0.1% formic acid; B was acetonitrile - methanol solution (11). Gradient. See Appendix A, Table A.1. Mobile phase flow rate. 0.3 mL/min. Column temperature. 35 ℃. Test solution temperature. 20 ℃. Injection volume. 10 μL. 6.4 Mass Reference Conditions Detection mode. multiple reaction monitoring (MRM), see Table 1 parent ion, ion and collision energy. See Appendix A scan In Figure A.1. Table 1 Ion Selective parameter table Aflatoxin Quantitative parent ion ion collision energy qualitative ion collision energy ionization mode M1 329.0 273.5 22 259.5 22 ESI Ion source control conditions. See Appendix A, Table A.2. 6.5 Qualitative Aflatoxin M1 sample peak retention time compared with the corresponding standard chromatographic retention time, the range of variation should be ± 2.5 %within. Reconstruction ion peak signal to noise ratio of aflatoxin M1 qualitative ions should be greater than or equal 3 (S/N≥3), reconstructed from a quantitative ion Sub peak signal to noise ratio should be greater than or equal 10 (S/N≥10). MS qualifier ion for each compound must be present, including at least a parent ion and two ions, and detect the same batch, The relative abundance of two ions of the same compound, the target compound in the sample than with comparable standard solution concentration compared to its tolerance Table 2 does not exceed a predetermined range. The maximum permissible relative ion abundances in Table 2 when qualitative deviations Relative ion abundances of > 50% > 20-50% of > 10% Zhi 20% ≤10% Allowing relative deviation of ± 20% ± 25% ± 30% ± 50% Each detection target compound retention time and two pairs of ions (ion-pair feature/quantitative ion pair) corresponding to the LC-MS/MS Peak area relative abundance qualitative. Require the retention time with the standard solution of the test samples of the target compound in the title compound Retention times were consistent (consistent with the proviso that the deviation is less than 20%), while the requirement is two pairs of ions in the test sample of the target compound Corresponding to the LC-MS/MS chromatogram peak area ratio of the standard solution consistent with the area ratio of the target compound. 6.6 Determination of the sample 6.3 and 6.4 in accordance with the conditions established by the determination of the test solution (6.2) and standard series solution (4.14) of aflatoxin M1 ion Strength, external standard. Appendix A chromatogram Figure A.2. Chromatographic retention time reference. aflatoxin M1 3.23 min. 6.7 blank test Not weighed sample according to step 6.5 of blank experiments. Confirm interfering substances should not contain the component being tested. 6.8 Standard curve drawing The standard series solution (4.14) from low to high concentration injection testing to the peak area - concentration plotted standard curve regression equation. 6.9 Quantitative Determination When the response test sample liquid component being tested should be within the linear range of the standard curve over the linear range, it should be washed with a blank sample matrix The solution was diluted to re-injection analysis or reduce the amount of sampling, re-processed according to 6.1 after injection analysis.

7 expression analysis

External standard, according to equation (1) to calculate the residual amount of aflatoxin M1. fVAX 1 ××× = (1) Where. X-- sample aflatoxin content of aflatoxin M1, in micrograms per kilogram (μg/kg); A-- sample concentration of aflatoxin toxin M1, in units of nanograms per milliliter (ng/mL); V-- sample volume size, units of milliliters (mL); f-- sample dilution factor; m-- specimen sample weight, in grams (g). The arithmetic mean of two under the same condition of independent determination results indicated that the results to three significant figures.

8 Precision

Two independent determination results under the absolute difference in repeatability condition must not exceed 10% of the arithmetic mean. The second method of immune affinity chromatography and HPLC purification Principle 9 Affinity column contains some aflatoxin M1 monoclonal antibody cross-linked to a solid support, when the sample through an affinity column, anti- Selective body with aflatoxin M1 (antigen) are bonded to form an antibody - antigen complex. Column the column was washed with water to remove impurities, and then washed with Degreasing agent adsorbed onto the column was eluted aflatoxin M1, collecting the eluent. Determination of eluate by high performance liquid chromatograph with a fluorescence detector Aflatoxin M1 content. 10 Reagents and materials Unless otherwise specified, the reagents used in this method are analytically pure water GB/T 6682 provided a water. 10.1 immunoaffinity column. maximum capacity of the affinity column is not less than 100 ng aflatoxin M1 (equivalent to 50 mL sample at a concentration of 2 μg/L), and When a standard solution containing 4 ng aflatoxin M1 (equivalent to 50 mL sample at a concentration of 80 ng/L) is not less than 80% recovery rate. Should regularly Check affinity column column efficiency and recovery for each batch affinity column at least once (see 10.1.1 and 10.1.2). 10.1.1 Column efficiency check Pipette (11.4) Pipette 1.0 mL of aflatoxin M1 standard stock solution (10.5.2) into 20 mL conical tubes (11.9). A constant current of nitrogen (10.3) will slowly dry the liquid, and then the residue was dissolved in 10 mL l0% aqueous acetonitrile (10.2.2), forced sway. This solution was added to 40 mL of water, mix well, all through the immunoaffinity column (10.1). According to the instructions require the use of immunity Affinity column. After rinsing immunoaffinity column, eluted aflatoxin M1. After the eluent appropriate dilution, using high-performance liquid chromatograph Immunoaffinity column bonded aflatoxin M1 content. Calculation of aflatoxin M1 recovery, which results in the desired Index 10.1 compared. 10.1.2 Check Recovery Pipette (11.4) Pipette 0.8 mL 0.005 μg/mL of aflatoxin M1 standard working solution (10.5.3) to 10 mL of water, Mix well, all through the immunoaffinity column. According to the instructions using immunoaffinity column. Leaching immunoaffinity column, eluted aflatoxin M1. After the eluent appropriate dilution, measured immunoaffinity column bonded aflatoxin M1 content by high-performance liquid chromatography. Calculation flavus Toxin M1 recovery, which results in the desired Index 10.1 compared. 10.2 acetonitrile (CH3CN). chromatography. 10.2.1 25% aqueous acetonitrile. A 250 mL acetonitrile (10.2) and 750 mL of water-miscible (degassed before use). 10.2.2 10% aqueous acetonitrile. A 100 mL acetonitrile (10.2) and 900 mL of water-miscible (degassed before use). 10.3 Nitrogen (N2). Chloroform 10.4. 0.5 to 1.0% mass ratio (mass ratio and chloroform) in ethanol stabilized. 10.5 aflatoxin M1 standard solution, the purity of ≥98%. 10.5.1 concentration correction Aflatoxin M1 standard chloroform solution at 10 μg/mL. According to the following method, the solution was measured at the maximum absorption band at Absorbance to determine the actual concentration of aflatoxin M1. At 340 nm ~ 370 nm was measured using a spectrophotometer at (11.11), net of chloroform blank background, read standard solution suction Luminosity values. Near 360 nm maximum absorption band at λmax, the measured absorbance value A, according to equation (2) to calculate the concentration values. 100 ×× = MAci (2) Where. ci-- aflatoxin M1 actual concentration, in micrograms per milliliter (μg/mL); A-- at λmax as measured at absorbance values; M - 328 g/mol, aflatoxin M1 molar mass in grams per mole (g/mol); ε - 19950, dissolved in chloroform aflatoxin M1 extinction coefficient, in units of square meters per mole (m2/mol). 10.5.2 Standard stock solution Determine the actual concentration of aflatoxin toxin M1 standard solution after (10.5.1), continue with chloroform and diluted to a concentration of 0.1 μg/mL stock solution. Stock solution sealed after the refrigerator below 5 ℃ stored. Under these conditions, the stock solution can be stable for two months. 10.5.3 aflatoxin M1 standard working solution Remove from the refrigerator standard stock solution (10.5.2) to reach room temperature, transfer a certain amount of stock solution was diluted to prepare a working solution. work For liquid prepared before use. Aflatoxin M1 standard working solution preparation. pipette (11.4) accurate Pipette 1.0 mL of stock solution (10.5.2) to 20 mL Conical tubes (11.9), with gentle nitrogen (10.3) and the solution was dry, and then with 20.0 mL10% aqueous acetonitrile (10.2.2) The residue was re-dissolved within 30 min shaking, mixing, formulated at a concentration of 0.005 μg/mL of aflatoxin M1 standard working solution. Using Reserve liquid nitrogen drying process, the operation must be careful to avoid condensation temperature is lowered too much. In making the standard curve, aflatoxin M1 absolute amount of injection are 0.05 ng, 0.1 ng, 0.2 ng, 0.4 ng. The high Dose-volume liquid chromatography sample loop with the working fluid to configure a range of appropriate concentration of aflatoxin M1 standard solution, diluted with 10 % Aqueous acetonitrile (10.2.2). 11 instruments and equipment 11.1 disposable syringes. 10 mL and 50 mL. 11.2 vacuum system. 11.3 Centrifuge. ≥7000 rpm rev/min. 11.4 pipette. 1.0 mL, 2.0 mL and 50.0 mL. 11.5 a glass beaker. 250 mL. 11.6 flasks. 100 mL. 11.7 water bath. temperature 30 ℃ ± 2 ℃, 50 ℃ ± 2 ℃, the temperature range of 36 ℃ ± 1 ℃. 11.8 filter paper. speed qualitative filter paper. 11.9 taper grinding mouth glass tube with a scale. 5 mL, 10 mL, 20 mL. 11.10 HPLC 11.10.1 pulse-free pump. for a constant volumetric flow rate of about 1 mL/min pump. 11.10.2 injection system. sample loop injection volume with fixed or variable volume of 50 μL ~ 500 μL. 11.10.3 reversed-phase column. Fill 3 μm or 5 μm octadecyl silica gel, plus a guard column filled with reversed-phase material. 11.10.4 fluorescence detector. excitation wavelength of 365 nm having a, 435 nm emission wavelength, under appropriate conditions can be measured chromatographic 0.02 ng Aflatoxin M1 (equivalent to five times the noise). 11.11 UV spectrophotometer. a wavelength range of 200 nm ~ 400 nm. 11.12 Balance. a sense of the amount of 0.01 g. 12 analysis steps All operations analysis should be carried out in the absence of light. 12.1 Sample Preparation 12.1.1 Milk. A sample in a water bath (11.7) was heated to 35 ℃ ~ 37 ℃. With filter paper (11.8) filter (depending on the circumstances, can be used more Layer filter paper filter), or 7000 r/min centrifugation 15 min. Collect at least 50 mL sample, proceed in accordance with 12.4. 12.1.2 Milk. Weigh 10 g sample (accurate to 0.1 g), placed in a 250 mL beaker (11.5) in. The preheated to 50 mL of 50 ℃ Many small water added to milk powder, it is mixed with a stirring rod evenly. If the milk powder is not completely dissolved, the beaker in a water bath of 50 ℃ (11.7) placed at least 30 min, carefully mix. The dissolved milk was cooled to 20 ℃ after, moved to 100 mL volumetric flask (11.6), and with Small amounts of moisture leaching times beaker, flask eluent moved together, with water up to the mark. Milk filtration with a filter paper (11.8), or 7000 rev/min centrifuged for 15 min. Collect at least 50 mL of milk samples in accordance with 12.4 proceed with the analysis. 12.1.3 fermented milk. According to "First Law" 6.1.2 pre-treatment methods. 12.1.4 Cheese. In accordance with the "First Law" 6.1.4 pre-treatment methods. 12.1.5 Cream. In accordance with the "First Law" 6.1.5 pre-treatment methods. Prepare 12.2 immunoaffinity column Connect the top of the disposable 50 mL syringe barrel (11.1) with an affinity column (10.1), and then the affinity column with a vacuum system (11.2) connect them. 12.3 Extraction and purification of the sample Pipette Pipette 50 mL sample (12.1.1 or 12.1.2) to 50 mL syringe (11.1), the regulatory vacuum system (11.2), Control sample to 2 mL/min ~ 3 mL/min flow rate through the column stable. Remove the 50 mL syringe fitted with 10 mL syringe. Syringe with a 10 mL of water was added, the column was washed with a steady flow, and then, Drained affinity column. Disengaging the vacuum system, and put on another 10 mL syringe, add 4 mL acetonitrile (10.2). Slowly push the syringe embolism, by column Cypriots control the flow rate, elution aflatoxin M1, the eluent was collected in conical tubes (11.9), the elution time of not less than 60 s. Followed by gentle Nitrogen (10.3) at 30 ℃ eluent was evaporated to a volume of 50 μL ~ 500 μL (If evaporated to dryness, lose aflatoxin M1). 10-fold diluted with water to a final volume Vf (i.e., 500 μL ~ 5000 μL). Note. If the sample liquid chromatograph injection containing aflatoxin M1, acetonitrile content exceeds 10%, peak broadening. If the water content exceeds 90%, No effect on the shape of the chromatographic peaks. 12.4 HPLC 12.4.1 chromatographic conditions Column. C18, length 25 cm, an inner diameter of 4.6 mm; Mobile phase. 25% aqueous acetonitrile (10.2.1); Flow rate. 1 mL/min. 12.4.2 aflatoxin toxin M1 of the standard curve According to HPLC sample loop volume, select the appropriate injection volume number Vi, were injected containing 0.05 ng, 0.1 ng, 0.2 ng And 0.4 ng of aflatoxin M1 standard solution. Drawn into the peak area or peak height of aflatoxin M1 quality standard curve. 12.4.3 chromatography According to the peak height or peak area in the chromatogram of the sample eluent aflatoxin M1, a standard curve obtained from the sample contained in the eluent Some of aflatoxin M1 mass (ng). If the sample eluent aflatoxin M1 peak area or peak height value is higher than the range of the standard curve, dilute the sample volume with water eluent After the re-injection analysis. 13 analysis results presentation 13.1 Milk Application of the formula (3) calculate the sample aflatoxin M1 content ωm. VV Vm fA m × ×× = 1ω (3) Where. ωm-- aflatoxin M1 content, in micrograms per liter (μg/L); Quality mA-- sample eluent aflatoxin M1 peak area or peak height obtained from the standard curve of aflatoxin M1, single Bit nanograms (ng); Vi-- eluent sample injection volume, in units of microliters (μL); The final volume of the eluent Vf-- sample units of microliters (μL); V-- immunoaffinity c...

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