HG/T 2984-198797 Analysis method for quinalphos technical (formerly GB 8204-87)
Some standard content:
UDC632.95：543.062
National Standard of the People's Republic of China
GB 8204—87
Analytical methods of content forquinalphostechnical
1987-09-17 Issued
National Bureau of Standards
1988-05-01 Implementation
National Standard of the People's Republic of China
Analytical methods of content forquinalphos technical
UDC632.95
GB8204—87
This standard applies to the determination of the content of quinalphos technical synthesized from O,O-diethylphosphinothioate and 2-hydroxyquinoline. Active ingredient: 0,0-diethyl-0-[quinolin-2-yl]phosphothioate. Structural formula:
—P(OC2H）2
Molecular formula: C12H15N20:PS
Molecular weight: 298.30 (International atomic weight in 1983) 1 Thin layer-quinoline phosphomolybdic acid weight method (arbitration method) 1.1 Summary of the method
When quinalphos original drug is developed in petroleum ether + acetone = 5 + 1, after thin layer separation, the organic phosphorus is oxidized to inorganic phosphoric acid under the action of an oxidant. Under acidic conditions, phosphoric acid reacts with quinomolybdic acid reagent to form a yellow quinoline phosphomolybdic acid precipitate. This precipitate is measured by weight, and multiplied by the conversion factor to obtain the quinalphos content. HsPO+3CgHN+12Na2MoO,+24HNO［(CgHN)HPO·12MoO）★+24NaNO+12H20
1.2 Reagents and solutions
Silica gel HF254+366 or GF254: for thin layer chromatography; Sulfuric acid (GB625-77): analytical grade;
Perchloric acid (GB623-77): analytical grade; Nitric acid (GB626-78 ): analytical grade;
Petroleum ether (HG3-1003-76): analytical grade; Acetone (GB686-78): analytical grade;
Sodium molybdate (HG3-1087-77): analytical grade; Citric acid (HG3-110881): analytical grade; Quinoline (沪Q/HG2-212-65: analytical grade; Sodium molybdate-perchloric acid-sulfuric acid solution: weigh 35g of sodium molybdate and dissolve it in 150ml of water, then slowly add 250ml concentrated sulfuric acid, add 200ml 70%~72% perchloric acid after cooling, shake well and set aside. Preparation of quinoline molybdate solution:
Solution I: Weigh 70g sodium molybdate and dissolve it in 150ml distilled water. Solution I: Weigh 60g citric acid and dissolve it in 85ml concentrated nitric acid and 150ml distilled water. Approved by the Ministry of Chemical Industry of the People's Republic of China on September 17, 1987 and implemented on May 1, 1988
GB820 4—87
Solution Processor: Slowly add solution I to solution I while stirring. Solution IV: Measure 5 ml of quinoline and dissolve it in a mixture of 35 ml of concentrated nitric acid and 100 ml of distilled water. Slowly add solution V to solution II, mix and stir well, let stand overnight, filter, collect the filtrate, add 280 ml of acetone, dilute to 1 L with distilled water, shake well and set aside.
Developing solvent: petroleum ether + acetone = 5 + + 1 (prepare before use) 1.3 Apparatus
Chromatography cylinder;
Dryer;
Chromatography glass plate: 200mm×200mm;
1ml syringe (with No. 4 needle);
scraper;
500ml suction flask;
30ml No. 4 glass sand core funnel;
30ml No. 4 glass sand crucible;
254nm ultraviolet lamp.
1.4 Determination steps
1.4.1 Preparation of thin layer plate
Weigh 5g silica gel HF254+36s (or GF254) into a 50ml beaker, add 14ml distilled water (depending on the quality of each batch of silica gel, the amount can be increased or decreased appropriately) and stir evenly into a paste. Pour it immediately onto a clean, dry chromatography glass plate and shake it gently to make the silica gel evenly distributed on the plate without bubbles. Place the plate horizontally (cured under an infrared lamp or at room temperature) to dry, and place it on a Activate in a 100℃ oven for 1 hour, cool slightly, take out, and store in a desiccator for later use.
1.4.2 Thin layer separation and determination
Take an activated thin layer plate, use a 1ml syringe to absorb an appropriate amount of quinalphos original drug, weigh about 0.1g (accurate to 0.2mg) by subtraction method, and spot it in a straight line 2.5cm away from the bottom edge of the thin layer plate (the two ends of the spot line are 1.5cm away from both sides), air dry to remove the solvent, and place it in a developing agent. Develop in a chromatography cylinder (the thin layer plate is immersed in the solvent for about 1 cm). When the solvent front rises to about 12 cm from the spot line, take out the plate and put it in a fume hood. Under an infrared lamp (no more than 40°C), evaporate the solvent. Under an ultraviolet lamp, use a needle tip to draw the outline of the quinalphos spectrum band (R~0.72). Use a scraper to scrape the silica gel of the quinalphos spectrum band into a 30ml glass funnel, and wipe the glass plate with a small amount of filter paper moistened with acetone, and put the filter paper into the glass funnel. Connect the glass funnel to a Kjeldahl flask and a decompression device, wash with acetone, and filter 5 to 6 times, 5 to 6 ml each time, and then immerse the Kjeldahl flask in hot water to evaporate the acetone. Remove the Kjeldahl flask, place it in a fume hood, add 10ml concentrated nitric acid, 10ml sodium molybdate, perchloric acid, sulfuric acid mixture, heat until a lot of white smoke comes out, remove and cool to room temperature, transfer the solution to a 40ml beaker, add 10ml of 1+1 nitric acid, heat to boiling, then add 50ml quinomolybdate solution, heat to slightly boiling, remove, filter under reduced pressure with a constant weight 30ml No. 4 glass sand crucible, wash the precipitate with water 8 to 10 times, place the glass sand in an oven at 180℃ for 45min, take it out and put it in a desiccator, cool to room temperature and weigh it to constant weight. Calculate the percentage X (weight ratio) of quinalphos in the sample according to formula (1): Xi=mi×0. 1349,
Wherein: m2—weighed weight of quinalphos original drug, g; m1—weighed amount of quinoline phosphomolybdate precipitate, g; 0.1349—coefficient of converting quinoline phosphomolybdate to quinalphos. 1.5 Method Deviation
The parallel deviation of this method should not be greater than 1.0%. 2 Gas Chromatography
2.1 Method Summary
GB8204—87
The sample is dissolved in acetone, n-heneicosane is used as the internal standard, 5% QF-1 + 3% DC-200 mixed stationary liquid is applied to ChromQ as the column filling material, and a hydrogen flame ionization detector is used to separate and determine quinalphos. 2.2 Reagents
Acetone (GB686—78): analytical grade;
Chloroform (GB682—78): analytical grade; Chromatographic stationary liquid: QF-1 and DC-200;
Carrier: GaschromQ (60~80 mesh); Internal standard: n-heneicosane (no impurities that are inseparable from quinalphos); Quinalphos standard: content greater than 98.0%. 2.3 Instruments
Gas chromatograph: hydrogen flame ionization detector, and can be equipped with glass column. Recorder or integrator.
Chromatographic column: 80cm long, 2-3mm inner diameter, polytetrafluoroethylene tube or glass column. Micro-syringe: 10μl.
2.4 Chromatographic column preparation
2.4.1 Coating of stationary liquid
Weigh about 20.0g of GaschromQ support and put it into a 100℃ oven for 2h. Weigh 1.00g of QF-1 and 0.60g of DC-200, place them in a small beaker, and completely dissolve them in a water bath in a fume hood with an appropriate amount of 1+1 acetone and chloroform mixed solvent (just enough to immerse the entire support to be coated). Pour 10g of the baked support into the above solution at a time, stir gently, mix evenly, then transfer to a culture dish, bake under an infrared lamp to completely evaporate the solvent, sieve, and take 6080 mesh. 2.4.2 Filling of the chromatographic column
Connect a small glass funnel to one end of the inlet of the chromatographic column, plug the other end with glass wool and wrap it with clean gauze to connect it to a vacuum pump, turn on the vacuum pump, slowly add the coated filler from the funnel, and continuously and gently vibrate the chromatographic column. After the filler is evenly and tightly filled, remove the funnel, turn off the vacuum pump, and plug the inlet with glass wool. 2.4.3 Aging of the Chromatographic Column
Connect the inlet end of the chromatographic column to the vaporization chamber of the chromatograph, and do not connect the outlet end to the detector first. Pass the carrier gas at a flow rate of 40ml/min, age the column at 250℃ for 24h, then cool it down, connect the outlet end of the column to the detector, and perform the measurement after the instrument baseline is stable. 2.5 Chromatographic operating conditions
Temperature: column chamber 190±2℃; vaporization chamber 230℃; detection chamber 230℃. Gas flow rate: carrier gas (N2) 140ml/min; hydrogen 60ml/min; air 630ml/min. Sensitivity: 1×104.
Paper speed: 5mm/min.
Quinthiophos retention time is about 457s.
Internal standard retention time is about 370s.
The above operating conditions are typical operating parameters. The analyst can make appropriate adjustments to the operating parameters according to the characteristics of the instrument to obtain the best effect.
2.6 Determination steps
2.6.1 Preparation of standard sample solution
Weigh 0.5g (accurate to 0.2mg) of standard sample and place it in a 25ml volumetric flask, dilute it to the mark with acetone, and shake it well. Then weigh 0.32g (accurate to 0.2mg) of internal standard and place it in another 25ml volumetric flask, dilute it to the mark with acetone, and shake it well. Use a pipette to draw 2ml from the above internal standard dilution and put it into four clean sample bottles respectively. Then use a pipette to draw 1.5, 2, 2.5, and 3ml from the above standard sample dilution and put them into the four sample bottles filled with internal standard dilution respectively, and shake it well. 2.6.2 Preparation of sample solution
GB8204—87
Weigh about 0.5g (accurate to 0.2mg) of the original drug sample containing quinalphos and place it in a 25ml volumetric flask, dilute it to the mark with acetone, shake it well, and use a pipette to draw 2.5ml into the sample bottle, then use a pipette to take 2ml from the internal standard dilution solution in 2.6.1 into the sample bottle, and shake it well.
2.6.3 Drawing of gas chromatography standard curve
Under the conditions of 2.5, after the instrument is stable, add 1μl of the standard sample solution each, and measure the peak area of the standard and internal standard. Use the mass ratio of the standard to the corresponding internal standard as the horizontal axis and the peak area ratio of the standard to the corresponding internal standard as the vertical axis to draw the quantitative standard working curve (this working curve should be calibrated frequently).
2.6.4 Determination of samples
Under the conditions of 2.5, after the instrument is stable, inject 1μ1 of sample solution and determine the peak area of quinalphos to internal standard substance in the sample. 2.6.5 Calculation
The percentage of quinalphos in the sample X2 (mass ratio) is calculated according to formula (2): ms×100
Wherein: ——The mass ratio of quinalphos to internal standard is found on the standard curve; mi—the amount of quinalphos sample weighed,;
ms——the amount of internal standard (n-heneicosane) weighed, g. 2.7 Method deviation
The parallel deviation of this method is not more than 2.0%. bZxz.net
Additional instructions:
This standard is under the jurisdiction of the pesticide standardization technology unit of the Shenyang Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Sichuan Chemical Industry Research Institute. The main drafters of this standard are Yu Changqing, Wu Bangdi, Zhong Zhiqing, and Zhao Zhenghong. 4
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