Study On The Detection Of 2-Aminobutane Residue In Fruit And Vegetables With Thin Layer Chromatography

2-AB is a kind of protective fungicide that is effective to a range of fungi. It is a preservative that is widely used in the storage of the orange, apple, pear, peach, banana, potato, green pepper etc. It is difficult to detect the residue of 2-AB by UV detector directly. The other low molecular weight aliphatic amines in some fruit and vegetables will interfere the detecting. To get an accurate result, it is necessary to convert 2-AB into its derivative by reaction between 2-AB and DNFB, and to separate 2-AB derivative from other derivatives by thin layer chromatography. In this paper, the conditions of deriving, TLC and quantitative analysis were studied. The selected procedures for detection of 2-AB residue in fruit and vegetables are as follows: take some slurry → add 75ml 1 mol/L CaCl2, 10g MgO and 150ml distilled water → distill with vapor → receive 80ml distillate fraction with 10ml 0.15 mol/L H2SO4 → adjust pH to 7 with 0.3 mol/L NaOH → dilute to 100ml with distilled water → get sample solution→ take 10ml sample solution into 50ml separatory funnel → extract with 15ml carbon tetrachloride for three times → transfer into 50ml conical flask with plug → add 5ml borate buffer liquid and 2ml DNFB, keep in water bath at 60 ℃ for 30 min → add 2ml 2mol/L NaOH and keep for another 30 min →cool with ice bath → extract with cyclohexane and discard water layer → wash with 15ml 0.05mol/L Na2CO3 for three times→ add 2g Na2SO4 without water to dehydrate → vaporize to dryness → resolve in 0.2ml benzene → spot 50ul solution on thin layer → spread with hexane: ether (70:30) → wash the 2-AB spot with chloroform and to make up to 5ml → detect under 332nm. A series of 2- AB standard solution are derived, separated and quantitative analyzed at same conditions with same methods. Using this method, the content of 2-AB haswonderful liner relationship with its absorbance value, the regress equation is Y=0.0121X-0.0071, R2=0.9945, the liner range is 1.25~25ng, the lowest detecting amount on thin layer is l(ig. The detection of some fruits and vegetables shows that the recoverage for pepper, garlic bolt, orange and grape are 101.2%, 88.5%, 85.7% and 89.2%, respectively, and the RSD for them are 7.9%, 5.4%, 7.7% and 4.1%, respectively.