GC 2,3-Xylenol GC 2,4-Xylenol GC 2,5-Xylenol GC 2,6-Xylenol GC 3,4-Xylenol GC 3,5-Xylenol LC Xanthine GC Xylenol GC LC Xylitol LC Xylobiose LC Xylose LC Xylotriose GC m-Xylene GC o-Xylene GC o-xylene GC p-Xylene GC xylene GC xylene isomers