| 摘要 |
PURPOSE: A method for quickly and effectively analyzing dithiocarbamate-based agrochemicals in citrus is provided to improve pretreatment speed by simultaneous isolation and methylation in one tube. CONSTITUTION: A pretreatment for analyzing dithiocarbamate-based agrochemicals in citrus comprises: a step of adding L-cysteine and EDTA solution to a cut sample and shaking; a step of adding tetrabutylammonium bisulfate solution and NaCl and adjusting to pH 7.0; a step of adding dichloromethane:n-hexane(volume ratio= 1:1) mixture solution and performing methylation; a step of centrifuging and collecting a solvent layer; a step of adding 20% 1,2-propanediol dissolved in dichloromethane; and a step of concentrating when only 1,2-propanediol remains, redissolving 1,2-propanediol with methanol, and filtering. [Reference numerals] (AA) Measuring a sample; (BB) Arranging 5g of shortly cut specimen into a 50ml tube; (CC) Solvent extracting; (DD) Adding 0.1g of L-cysteine and 20mL of 0.25M EDTA(0.45M NaOH) solution, and shaking; (EE) Adding 1.5mL of 0.41M tetrabutylammonium bisulfate solution and 3g of NaCl, shaking and mixing, and adjusting pH to become around 7.0 using 2M HCl; (FF) Derivatization(methylation); (GG) Adding 15ml of dichloromethane:n-hexane(1:1) mixed liquid containing 0.05M methyl iodide in the extract liquid, strongly shaking and mixing for 5 minutes, and leaving for about 10 minutes; (HH) Centrifuging; (II) Centrifuging at 3000rpm for 3 minutes, extracting 6ml of a solvent layer(upper layer), and adding 0.2ml of 20% 1,2-propanediol dissolved in dichloromethane; (JJ) Concentrating and filtering; (KK) Concentrating at 30°C until only 1,2-propanediol remains, redissolving with 2ml of methanol, and filtering with 0.2um syringe filter, and instrumentally analyzing; |
