Score plotofPC1andPC2.Variables:FT-RamanCHbanddatapoints
(step¼2 cm−1), items:37referencesamples.Somesamplesareclustered
(ex:glues),somearedispersed(ex:pineresins)andsomearegroupedbutamong
another kindofmaterial(ex:frankincenseswithinthediterpenicresins).