Fig. 6From: Advances and key considerations of liquid chromatography–mass spectrometry for porcine authentication in halal analysisPCA scoring a and loading plots b for tortoise shell glue ( ), deer-horn glue ( ), porcine gelatin ( ), bovine gelatin ( ), and donkey gelatin ( ). (Cheng et al. 2012) Copyright (2012) with permission from ElsevierBack to article page