This standard specifies the method for determining the residues of monoformamidine in fruits. This standard is applicable to the determination of the residues of monoformamidine in fruits. GB/T 5009.160-2003 Determination of the residues of monoformamidine in fruits GB/T5009.160-2003 Standard download decompression password: www.bzxz.net

CS 67. 040
National Standard of the People's Republic of China
GB/T5009.160—2003
Determination of serniaitraz residues in fruits
Determination of serniaitraz residues in fruits2003-08-11Promulgated
Ministry of Health of the People's Republic of China
National Standardization AdministrationWww.bzxZ.net
2004-0T-01Implementation
This standard is issued and managed by the Ministry of Health of the People's Republic of China. GE/T5009.160—2003
The responsible units of this standard are: Food Hygiene Supervision and Inspection Institute of the Ministry of Health, Beijing Municipal Health and Epidemic Prevention Station, Beijing Institute of Fashion Technology. The main responsible persons are: Zhang Tang, Shu Kaikun, Sun Chun, Li Liping. The Ministry of Health shall entrust the technical responsible unit, Food Hygiene Supervision and Inspection Institute of the Ministry of Health, to review and interpret this standard. 335
GB/T 5809.160—2009
Monomethyl 1nom.itE2) Chemical name - (2,4-dimethylamino) - methyl 2-hydroxy-1,4-dimethylamino, a group of insecticides, has been registered in my country's citrus and apples. my country stipulates that the limit of monomethyl 1nom.itE2 in the residue of citrus and apples is 0.5 g. This standard provides a method for detecting the residue of monomethyl 1nom.itE2 in fruits. This standard specifies a method for determining the residue of monomethyl 1nom.itE2. This standard is not suitable for the micro determination of the residue of monomethyl 1nom.itE2 in fruits. The detection limit of this method is 0.025 mg/kg. The detection range is 0.2 g/mL~1000 g/mL. 2 Principle
|GD/T5009.160—2003
The mono- and di-isocyanate in the sample is extracted with hydrochloric acid, and after purification by dimethicone extraction, it is determined by a commercial batch chromatography instrument with an ultraviolet detector, and the qualitative analysis is based on the retention time of the chromatographic peak. The peak height is determined by the external standard method. 3 Reagents
3.1 Dimethicone is redistilled twice.
3.2 Distilled alcohol (optional). Use a solvent extraction device and filter through a 0.5μm organic filter membrane. 3.3 Distilled water (double screen), use a solvent extraction device and filter through a 0.45μl water filter membrane: 3.4 Ammonium acetate.
3.5.2mn/L. Acid.
3.61.1rmz/f. Hydroxide solution.
3.7 Sodium hydroxide: Dry with 1307 for 5h + water. 3.8 Aemiamitrz standard: purity>R% 4.1 Commercially available phase chromatography, equipped with UV detector, solvent filtration device, ultrasonic cleaning instrument. Oil-free vacuum pump, low-speed high-speed centrifuge, 1u001/min~Mkir/min4.5 KD concentrator. 10ml. Graduated centrifuge tube. Pointed suction pipette: diameter: mm.
100% liquid required
5 Analysis steps
5.1 Sample processing
5.1.1 Extraction
Peel the oranges, remove the surface sand, beat the oranges with a homogenizer, accurately weigh 4 g of fruit pulp (sieved to 0.001 g) in a 1 mL centrifuge, add 0.2 mol/L salt, and adjust to 1 mL. Place the centrifuge in a sonic flow section for ultrasonic extraction for 1 h. Use a pointed pipette to accurately absorb the upper phase and obtain 5 ml. Add 357
CB/T5009.160—2003
1.0m/s of sodium ammonia solution into a 10CmL separatory funnel and adjust the pH value to 13~13. 5.1.2 Purification
Add 1C, 10m, 0mL of trichloroethane into the above 100ml separatory funnel, vibrate for 24 hours, let it stand and separate the layers, collect the lower organic phase, combine all the extracted liquids, and pass them through a funnel filled with anhydrous sodium dextrose for dehydration, add 10mL of methanol, and concentrate to 1mL with a KD concentrator. For HPLC analysis, 5.2 Determination
5.2.1 Liquid chromatography, please refer to the conditions
Column: 3.5×109mmos sample (5um>, mobile phase + methanol + ammonium acetate solution (0.01n0)/1.) 75+25+: L/min
UV detection wavelength: = 254 nm.
5.2.2 Preparation of standard curve
Use a precision balance to weigh 5lnig of monomethyl methacrylate standard (converted to c.1ng), dehydrate in methanol, and determine the concentration to be 50mJ., and obtain a monomethyl methacrylate standard stock solution with a concentration of 100g/m. Take this stock solution and dilute it in turn to prepare standard samples with concentrations of 0.2.1.D.5.V.1050 and 10R/mL respectively, collect each L of the standard solution and inject it into high performance liquid chromatography analysis according to the lower concentration to the higher concentration. Results A standard curve was prepared according to the relationship between height and concentration. Figure 5.2.3 Chromatographic analysis. The sample was aliquoted and filtered through a microporous filter. The retention time and height of the chromatographic peak were recorded. The retention time was used for qualitative analysis. The external standard method was used for quantitative analysis based on the peak height. Figure 5.2.4 Chromatograms Figure 1 HPLC graph of single-flagellate standard sample Figure 2 HPLC graph of apple spiked sample Figure 3 LC graph of spiked citrus sample
Fruit shrinkage calculation
Calculate according to the following formula:
In the formula,
X is the amount of methyl ester in the sample, in milligrams per gram (mg/kg); A is the amount of methyl ester in the sample, in nanograms (g); Yi is the volume of the sample solution, in liters (nL); V is the volume of the sample, in microliters (L);
is the mass of the sample, in grams (g);
GR/T5009.160-203
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