# Chemical Migration from Wine Contact Materials
## 5 Wine Migration Studies on Chemical Contaminants
### Analytical Methods
#### 5.2.1 Gas Chromatography  
Gas chromatography-mass spectrometry was used in the past for the determination of the phthalate plasticizer Bis(2-ethylhexyl) phthalate (DEHP) after liquid-liquid extraction with dichloromethane (CH\({}_{2}\)Cl\({}_{2}\)) reporting non-detectable findings, below 50 ng/mL, without further details on the acquisition of mass spectrometric data [71]. GC-MS analysis has been reported for the determination of certain phthalates (dimethyl phthalate; DMP, dibutyl phthalate; DBP, benzyl butyl phthalate; BBP, and DEHP), alkylphenols (4-n-Nonylphenol; NP and 4-n-octylphenol; OP), BPA, and bis(2-ethylhexyl) adipate (DEHA) with limits of detection at ppt level ranging between 17 ng/L (NP) and 451 ng/L (DEHP) [36]. The method included solid phase extraction with the polymeric sorbent Oasis HLB and elution with combinations of dichloromethane, hexane, and acetone prior to GC-MS analysis and acquisition in selected ion monitoring (SIM) mode using three ions per compound [36]. Gas chromatography was also used in the past for the determination of organotins after migration tests with agglomerated corks and wine [72]. Prior to GC analysis, hydride derivatization and headspace solid phase microextraction (HS-SPME) with poly-(dimethylsiloxane) (PDMS) coated fibers were applied, while the quantification of the derivatized organotins was performed with flame photometric detector (FPD) and their identification with a mass spectrometer in full scan mode and comparison of the spectrum with that of derivatized standards. According to the reported findings, monobutyllin in wine increased with time until it reached 24 \(\upmu\)g of Sn/L after a 30-day period, while dibutyltin increased in the first 5 days and then was maintained around 4 \(\upmu\)g of Sn/L [72]. The abovementioned studies concern target analysis for a limited number of compounds using standard compounds for the identification of the analytes. An untargeted approach applying GC-MS methodology was recently reported for the screening of volatile compounds migrating from EVA corks to wine simulant [74]. Solid phase micro extraction (SPME) with PDMS fiber coating was used for the isolation of the analytes from the wine simulants. The acquisition was carried out in scan mode over the range of 50-450 \(m/z\), and the identification of each migrant was based on the comparison of the spectra of each chromatographic peak unique to the sample to the NIST and WILEY mass spectra libraries, as well as on the analysis of commercial standards when available [74]. This study resulted in the identification of five compounds, three of them, the butylated hydroxytoluene (BHT), its potential impurity 2,6-bis(1,1-dimethylethyl)-4-ethyl phenol, and 7,9-ditert-butyl-1-oxaspiro [4.5] deca-6,9-diene-2,8-dione were identified with commercial standards. The other two eluted peaks were identified based on mass spectra library matches as the alkanes (i) 2,2,4,4,6,8,8-heptamethyl nonane and (ii) 2,2,4,6,6-pentamethyl heptane. There were two more eluted chromatographic peaks that could not be identified based on library matches; however, based on characteristic features of their spectra, it was hypothesized that they included branched alkanes. The identified BHT and 2,6-bis(1,1-dimethylethyl)-4-ethyl phenol belong to the intentionally added substances since they are included in the European Union List of the authorized compounds as additives or polymer production aids (Reg 10/2011) and their SMLs are 3 and 4.8 mg/kg, respectively. The alkanes and 7,9-ditert-butyl-1-oxaspiro [4.5] deca-6,9-diene-2,8-dione belong to the Non-Intentionally Added Substances (NIAS), and their origin was not concluded. The limits of detection (LODs) of the method ranged between 0.3 and 0.5 \(\upmu\)g/kg, and the concentrations found were up to 15 \(\upmu\)g/kg for BHT [74]. More detailed findings on the concentrations are presented in Table 2. It is noted that the present study used two simulants, 3% \(v/v\) aq. acetic acid and 20% \(v/v\) aq.