Analysis of Compounds Formed by Acid Hydrolysis

Accurate studies of grape juice and wine matrix effects in the headspace (HS)-SPME analysis of 3-alkyl-2-methoxypyrazines using a triphase fiber divinylbenzene-carboxen-polydimethylsiloxane (DVB/CAR/ PDMS) was reported by Kotseridis et al. (2008). Also, PDMS/DVB and CAR/PDMS were selected as suitable fibers for analysis of wines (Sala et al., 2002 Galvan et al., 2008 Ryan et al., 2005). The optimized analytical conditions found are described in Table 4.2. 

Increasing the ethanol content in the sample to 20% v/v induced an exponential decrease of recoveries. Best results were obtained by adjusting the sample at pH 6 and wine dilution 1 2.5 before extraction 

GC column Poly(ethylene)glycol (PEG) bound-phase fused-silica capillary (30m x 0.25 mm i.d. 0.25-pm film thickness) 

Injector Temperature 200°C, sample volume injected 0.5 pL, splitless injection 

MS conditions Ionization energy 70eV, transfer line temperature 280°C, SCAN mode 

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