author:seohtm Add the Time:2015-7-7 17:04:41 Click: 758

The sample was extracted with acetone, peracetic acid oxidation, Florisil column chromatography (Florisil) purification, gas chromatography (FPD) determination.
1 main instruments and equipment
Gas chromatograph: with flame photometric detector (FPD, sulfur filter)
Mill
Oscillator
Rotary evaporator
Glass column: 18cm (long) * 1.5cm (inner diameter)
2 main reagent
Acetone: analysis of pure, heavy distillation
Dichloromethane: analysis of pure, distilled
Petroleum ether: 60 ~ 90, analysis of pure, heavy distillation
Florisil (Florisil): 60 ~ 100 mesh, using chromatography
Oxidant: glacial acetic acid /30% (1:1, V/V), mixed with 1% concentrated sulfuric acid in hydrogen peroxide, the preparation of 4 hours after use, to avoid light storage, 7 days after re preparation
Aldicarb standard sample: purity 99.4%
Aldicarb sulfoxide standard sample purity: 99.9%
Aldicarb sulfone standard sample purity: 99.8%
3 detection steps
3.1 extraction
3.1.1 cottonseed: said 50g crushing cottonseed samples, add 300 ml of acetone, 20g anhydrous sodium sulfate, soaking overnight oscillation extracted for 4 hours, filtering, take 1 / 2 the filtrate volume (25g samples), plus 4ml oxidation agent, 30min after mixing with 40ml 10% sodium bicarbonate solution, stirring for 20min, and 150 ml of distilled water, with 3 x 50 ml dichloromethane extraction, collect liquid extraction and drying with anhydrous sodium sulfate and concentrated to about 50ml.
3.1.2 soil: said 100g 40 mesh sieve samples, with 300 ml of acetone / water (1: 1, V / V), the oscillation extraction 3h, filtration, take 1 / 2 the filtrate volume (50g samples), add 8ml oxidation agent, 30min after mixing with 80ml 10% sodium bicarbonate solution, stirring for 20 min and then add 50ml distilled water and 3 x 50 ml dichloromethane extraction, collect liquid extraction and after drying with anhydrous sodium sulfate, evaporated to near dryness, plus a small amount of acetone, then concentrated to about LML, fixed volume measured.
3.2 column chromatography purification
The lower ends with 2cm thickness of anhydrous sodium sulfate on the column, the middle 10g Fuluoli silica. With 10 ml of dichloromethane pre leaching, cottonseed samples extraction concentrated liquid is transferred to the column, first with 50 ml of acetone / petroleum ether (2:8, V / V) leaching, abandoned to pour the liquid, then 60ml / acetone petroleum ether (1:1, V / V) elution, collecting pour out liquid and concentrated to near dryness, plus a small amount of acetone to concentrated to about LML, fixed volume to be measured.
3.3 determination of gas chromatography
Detector: flame photometric detector (FPD, sulfur filter)
Column: 2m (long) * 3mm (inner diameter) glass column
Chrom Q Gas, 60 ~ 80 mesh
Fixed liquid: 4%Carbowax20M
Temperature: 300, 250,, 160
Carrier gas: nitrogen (more than 99.9%), 60ml/min
Combustion gas: 30ml/min, air 30ml/min
Retention time: aldicarb sulfone 6min5s,