Fast Differential Analysis of Propolis Using Surface Desorption Atmospheric Pressure Chemical Ionization Mass Spectrometry

Table 2

The loadings and scores for the first three rotated principal components.

	The loadings				The scores
	[M–H]^−	PC1	PC2	PC3	Sample number	PC1	PC2	PC3
A^a	78	−0.157	−0.441	−0.159	1	−1.145	−0.105	−0.262
	92	0.139	−0.311	−0.186	2	1.555	−1.286	1.080
	93	−0.271	0.556	0.190	3	−0.747	−0.809	−0.360
	94	−0.341	−0.205	−0.357	4	−0.065	−0.468	−0.058
	102	−0.199	0.558	0.190	5	−0.519	−0.625	−0.010
	121	−0.629	0.134	0.096	6	1.369	−0.370	−3.764
	124	0.565	−0.416	0.128	7	1.019	−0.501	0.279
	151	−0.049	0.287	−0.552	8	−1.192	−0.533	0.052
	154	−0.338	0.434	0.103	9	−0.002	−0.241	−0.825
	183	−0.184	0.545	−0.294	10	0.070	−0.344	−0.071
B^b	253	0.685	0.610	0.091	11	−0.985	0.717	−0.212
	255	0.227	0.629	−0.207	12	−0.856	−0.588	0.125
	269	0.593	0.541	−0.061	13	−0.202	1.338	0.629
	271	0.372	0.670	0.084	14	1.358	−0.087	−0.691
	283	0.752	0.268	−0.132	15	−0.418	−0.347	0.349
	313	0.947	0.003	−0.182	16	0.400	0.329	−0.500
	247	0.929	−0.038	0.023	17	−0.588	0.985	−0.235
	303	0.816	0.482	0.079	18	0.958	0.446	0.682
	163	0.035	0.566	0.050	19	−1.020	1.451	−0.252
	177	0.259	0.807	0.064	20	−1.202	−0.801	−0.001
	229	0.511	−0.165	0.731	21	−0.433	−0.235	0.825
	267	0.913	0.221	−0.050	22	−0.579	1.695	0.960
	285	0.660	0.314	0.175	23	−0.109	2.384	0.561
					24	0.437	−1.205	1.700

Bold font indicates high correlation. ^aThe most abundant ions for SDAPCI-MS fingerprints of samples in this paper; ^bSome abundant ions for fingerprints of propolis samples by other MS methods (Pietta et al., 2002 [1]; Sawaya et al., 2004 [27]). PC: principal component.