Analysis of resin in eucalypt woods and pulps

A procedure is described for determining resin components in eucalypt woods and pulps, involving Soxhlet extraction of freeze dried woodmeal and pulp samples with dichloromethane, and examination of the trimethylsilylated ext racts by gas chromatography (GC) with detection by mass spectrometry (MS) a nd flame ionisation. The major resin components of eucalypt woods and pulps were found to be steryl esters, chiefly sitosteryl linoleate and oleate. M inor components were fatty acids, mainly linoleic and oleic acids with smal ler amounts of acids ranging from C-16 to C-26, sterols (chiefly sitosterol together with some sitostanol), and triglycerides. Extraction with more po lar solvents (acetone and methanol) yielded little additional amounts of re sin components, but afforded gallic and ellagic acid, the latter interferin g with the GC determination of sterols. Seasoning of Eucalyptus globulus wo odchips gave reduced amounts of resin, largely through a reduction in the s teryl ester fraction. Examination of E. globulus woods and pulps showed tha t most of the original resin remained in the pulps after sulfite pulping, a lthough only small amounts of resin remained after kraft pulping. About hal f of the original resin remained in sulfite pulp after bleaching with perox ide. Analysis of fractionated bleached eucalypt sulfite pulp showed that th e greatest concentration of resin resided in the fines fraction.