Establishment Of Detection Methods And Research Of The Migration Regularity For TCA In Wine

Cork contamination has become more common and urgent problem in wine industry,mainly caused by 2,4,6-trichloroanisole(TCA)contamination.TCA is a metabolite produced by fungi,which arises from O-methylation of 2,4,6-trichlorophenol(TCP),just as mould present a detoxification in the cork.TCA in wine could emit musty and the smell corked into wine bottle,which affects the sensory quality of wine and results in serious losses to the wine industry.Therefore,it's very significant to establish a rapid and effective method to detect the contents of TCA in wine and examine the migration patterns of the content of TCA from cork into wine,which not only can be an effective evaluation of TCA contamination,but can effectively control the quality of wine in the process of prodution and storage,so as to meet the requirement of controlling pollution situation.This study aims to establish a method to detect the TCA in wine and research the rule of TCA in wine by different types of cork sealing the wine bottle for 180 days,which lay the foundation for selecting proper corks and controlling the content of TCA in wine.Firstly,a method for determination of TCA in wine has been established by combining headspace solid-phase microextraction(HS-SPME)and gas chromatography with mass spectrometry(GC-MS),and the operating conditionts of the instrument were optimized.Secondly,the extraction conditions of TCA in wine by using HS-SPME-GC-MS were optimized through design-expert experiment,including types of fibre,volume of sample,extracting temperature,time,balance time,tc.Thirdly,three kinds of corks(synthetic,natural and filling corks)soaked in nine kinds of wines and the wine were bottled by synthetic,natural and filling corks,respectively.The soaking and bottled wines were stored for180 days.All the wines were tested for TCA contents at measured intervals of 1 day,7 days,15 days,30 days,60 days,90 days and 180 days.The results of the mobility of TCA in the process of storage are as follows:The method for the determination of TCA in wine was established by using HS-SPME-GC-MS,and all the preparation of samples met to the ISO20752-2014 method.The result of the determination was the coefficients R² of determination 0.999 9,repeatability RSD less than 5%,and recovery rates between 95.7%and 106.1%.Limits of detection and quantification were 0.6 ng/L and 2 ng/L,respectively,below their sensorial threshold level in wine.The result showed the precision,stability and reproducibility of the method,are good,and reliable.The objectives of this study,was the development of an analytical method for the determination of 2,4,6-trichloroanisole(TCA)in wine and optimization of the method through design-expert.The results showed,polydimethylsiloxane/divinylbenzene(PDMS/DVB,65?m)was selected as the extraction fiber,optimized parameters for SPME were 9.8 m L of wine,2 g of Na Cl,temperature 33?,equilibration time 10 min and extraction time 90 min,the following analysis by GC-MS and quantification by using TCA-d₅ as internal standard.The method showed,with the coefficients R² of determination was 0.999 9,RSD was 1.03%,and recovery rates was between 95.7 and106.1%.Limits of detection and quantification were 0.3 ng/L and 1 ng/L,respectively.The optimized method was applied to determine 7 domestic and 16 foreign wines.The examination result reveals the content of TCA varying between 0 and 7.6 ng/L.The content of TCA in wine is lower than in dry red wine.This method is simple and reliable,and can be applied to the determination of TCA in wines.The results of the migration rule for three kinds of corks which were soaked in the red wine,then sealed the wine bottle:1)the TCA dissolution rate of three types of rose wine soak reached to the maximum on the first day.The content of TCA in natural and filling corks soak solution were maximum in 15 days;after 60 days,the TCA in synthetic plug soaking tend to be balanced.2)the migration rate of bottled red wine was maximum in the seventh day;the content of TCA in the bottled wine with 3 kinds of corks gradually were constant after 90 days.The results of the migration rule for three kinds of corks which were soaked in the dry wine,then sealed the wine bottles:1)the TCA dissolution rate of three types of dry white wine soak reached to the maximum on the first day.The content of TCA in natural plug,filling cork and synthetic plug soaking solution were maximum in 30 days,15 days and 90 days,respectively.2)the migration rate of bottled white wine was maximum in the seventh day;the congtent of the bottled wine with natural and filling corks gradually flattened after 15 days,and TCA in synthetic cork bottled wine was no longer increases after 90 days.The results of the migration rule for three kinds of corks which were soaked in the rose wine,then sealed the wine bottles:1)the TCA dissolution rate of three types of rose wine soak reached to the maximum on the first day.The content of TCA in natural plug,filling cork and synthetic plug soaking solution were maximum in 15 days.2)the migration rate of bottled rose wine was maximum in the seventh day;the content of TCA in the bottled wine with natural and filling corks gradually flattened after 90 days,and the content was around 2 ng/L;TCA in synthetic cork bottled wine was increasing during 180days.To sum up,this study established a rapid and effective method of detection TCA in wine,providing theoretical and data basis to form local or national standards.During storing 180 days,the research studied the contact interaction cork and wine,and got the different TCA maximums dissolution and migration regularities in different wines,which provide data base for selecting corks reasonably and reduce the TCA contamination in wine.