The primary column (situated in GC1), a Supelcowax-10 (100% polyethylene glycol) 30 m × 0.25 mm ID × 0.25 m df
(Sigma-Aldrich/Supelco),was connected to position 1 of a 7-port wafer chip (SGE, Ringwood, Victoria, Australia), after passing through the heated transfer line. An SLB-5ms 10 m × 0.53 mm ID × 0.10 m df capillary [(silphenylene polymer, practically equivalent in polarity to poly(5% diphenyl/95% methylsiloxane)] (Sigma-Aldrich/Supelco) was used as second analytical column. A 1.5 m × 0.25 mm ID segment of uncoated column was used as restrictor,