Rapid Determination of Three Methyltin Compounds in Wine by Headspace-gas Chromatography after In-situ Ethylation

KeyWord:methyltin  wine  ethylation  headspace  gas chromatography and flame photometric detection(GC-FPD)

Abstract:

      A method for the simultaneous determination of trimethyltin(TMT),dimethyltin(DMT) and monomethyltin(MMT) in wine was developed by headspace extraction coupled with gas chromatography and flame photometric detection(GC-FPD) after in-situ derivatization with sodium tetraethylborate(NaBEt4).The headspace conditions(temperature,time and oscillating mode),derivatization parameters(amount of NaBEt4,pH value and salinity) and GC conditions were optimized.In the optimal experimental conditions,the limits of detection(LODs) were 1.2£¬1.0,1.2 ¦Ìg/kg for TMT,DMT and MMT,respectively.For the three representative matrices of dry white,dry red and pink wine,the average recoveries at three spiked levels of 5.0,10.0,100.0 ¦Ìg/kg were in the range of 80.5%-101.4%,and the relative standard deviations(RSDs,n=6) ranged from 3.2%to 8.5%.The proposed method was validated to have high sensitivity and high accuracy,also with the special advantages of simplicity and rapidness.The total analysis time for one sample is not more than 25 min by the proposed method,and it is suitable for the rapid screening of methyltin compounds in wine.