This standard specifies the determination of the content of dimethoate and nereisin in rice by gas chromatography. This standard is applicable to the determination of dimethoate and nereisin residues in rice. The detection limit of this standard is 0.1ng, and the detection concentration is 0.002mg/kg. GB/T 5009.114-2003 Determination of dimethoate residues in rice GB/T5009.114-2003 Standard download decompression password: www.bzxz.net

ICS.67.040
National Standard of the People's Republic of China
GB/T5009.114—2003
Determination of bisultapresidues in rice
Determination of bisultapresidues in rice2003-08-11Promulgated
Ministry of Health of the People's Republic of China
National Administration of Standardization of China
Implemented on 2004-01-01
CE/T5QQ9.114—2003
This standard replaces GB/T24929.8:1994 Determination of bisultapresidues in rice The main effects of this standard G/T14929.A-1691 are as follows: The Chinese name of the standard has been modified. The Chinese name of the standard has been changed to "Determination of the quantity of insecticides in China" (B/T2CC51.4-2001 Standard Specification for Chemical Analysis Methods for the Determination of the Quantity of Insecticides). The structure of the source standard has been modified.
This standard is proposed and approved by the Ministry of Health of the People's Republic of China. The responsible unit for the standard is: Institute of Dermatology, Chinese Academy of Sciences. The main responsible persons for this standard are Lin Yuanqi and Chen Daodian. The original standard was first issued in 1994, and this is the first revision. 5||tt ||Determination of chloramphenicol residues in ricebzxZ.net
This standard specifies the determination of chloramphenicol and chloramphenicol residues in rice by phase chromatography. This standard is applicable to the determination of chloramphenicol and chloramphenicol residues in rice. The standard detection limit is 1g: the detection accuracy is 1.rgk. 2 Principle
CB/I5009.114—2003
Rice test material is extracted with 5.mol/L hydrochloric acid, converted into chloramphenicol in an acidic solvent, extracted with dichloromethane, and then distilled to 3 ml in 10% distillation. The volume is adjusted to 1 ml in 10% distillation cycle and determined by FPT>-GC. 3 Reagents
3. 0.1ol/
3.2n.[ml/I sodium hydroxide.
3.3.1mL/L sodium sulfide aqueous solution,
3.4 ​​medium alcohol weight
3.5 trichloromethane: five distilled alcohol with water to make it contain 1 head of ethanol, 3.6 anhydrous alcohol,
3.7 anhydrous chlorinated alcohol
3.8 standard chlorinated sodium salt: confirm that the salt is 0.0160 and the solution is well dissolved to 100mT. per liter, and the total amount of each element is 1. According to the needs, aspirate the quantitative standard solution, and use the chlorinated sodium salt to determine the volume to prepare the corresponding solution. 4 According to
4.1 benchtop centrifuge initial.
4. 7 Rotary generator.
4.3 Ramp amplifier.
4.4 Nitrogen heater.
4.5 Gas chromatograph (with flame photometer, FP[3]): 4.6 Micro syringe.
5 Analysis steps
5.1 Sample treatment
Weigh 100 g of rice sample (viscosity 0.001), add 10 mL.1 mu l/L hydrochloric acid solution, shake on a shaker for 35 min. Centrifuge at 600 1/min for 10 min, pour the supernatant into a covered dish, and then wash the sample with 1 ml.u.tmal/L hydrochloric acid. Repeat this process three times. Combine the hydrochloric acid extracts, adjust the pH to 3.59, add 0.1 ml/1.0 sodium hydroxide solution, 2 mL, and place in a separatory funnel. Vibrate vigorously and let stand to separate. Pass the methyl ether layer through anhydrous acetone and filter into a conical flask. Distill off the chloroform in a rotary evaporator at 45 °C. When a little is left, take it out immediately and dilute it to 1 mL with alcohol. 5.2 Gas chromatograph spare parts
5.2.1 Chromatographic column
m inner diameter (m) x 2m, the maximum span is 11 cm3 (mm~1.1 mm). 5.2.2 Source corrosion
Column temperature: 160℃
CB/T 5009.114-2003
Vaporization room temperature: 200℃;
FPT) detector short: 17℃:
5. 2. 3 Gas temperature
Gas recirculation) flow rate: 70mL/min
Room gas flow rate, 15mL/in
Air flow rate: 50mL/min.
5.2.4 Other conditions
Only sensitivity: 10
Micro: 32;
Paper: 0.5cta/min
Adjust the instrument according to the above reverse color conditions. After the instrument is stable, inject the sample or standard pool with a micro syringe, and use the retention time as the qualitative indicator.
Take a small amount of nereidazole ion equivalent to 0.5U, 1.0, 2.0, 3.0, 4.0U, 5.0, inject it into the chromatogram, and measure the amount. Plot the work on the double logarithmic coordinate paper with the nereidazole content as the vertical coordinate and the peak height as the vertical coordinate, and quantify the peak height according to the test. The linear range of the toxin is .50~5.0
The standard sand toxin is converted into sand by the standard sand toxin:
?——The nereidazole is converted into blue,
Figure 1 The color of nereidazole toxin
6 The results are calculated as follows:
where the impurity content is expressed in grams per gram (mg);
the height or area of ​​the sample is measured; the toxicity of the sample is expressed in grams (1%); R
constant volume is expressed in liters (L);
A is expressed in liters (p);
sample mass is expressed in grams (g);
the effective dose is 355 and the amount of chloramphenicol is 14! Multiply the obtained amount by 2.38 to obtain the amount of chloramphenicol. The result is rounded to two significant figures.
7 Precision test: The absolute difference between two independent determinations obtained under repeated conditions shall not exceed 15% of the arithmetic mean. 72
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