Table 2. Comparison of the concentration of amines in pooled DBS samples.

Amine	Concentration in DBS in μM								%error in calculation using area ratio
	From calibration curve				From area ratio
	DBS1	DBS2	DBS3	Mean	DBS1	DBS2	DBS3	Mean
Histidine	7.4	6.4	7.5	7.1	7.5	6.5	7.7	7.2	1.5
Hydroxy proline	3.1	2.8	3.8	3.2	3.0	5.4	3.8	4.1	25.7
1-Methylhistidine	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1	−14.0
3-Methylhistidine	1.3	1.3	1.2	1.3	1.1	1.2	1.1	1.1	−10.3
Arginine	12.6	12.7	13.7	13.0	12.7	12.8	13.8	13.1	0.7
Ethanolamine	2.4	2.1	2.7	2.4	2.5	2.2	2.7	2.5	2.7
Serine	48.7	49.7	52.2	50.2	43.1	44.0	46.2	44.4	−11.5
Taurine	59.7	56.8	67.5	61.3	60.1	57.1	67.9	61.7	0.6
Sarcosine	6.1	6.1	7.8	6.7	6.0	6.1	7.7	6.6	−1.1
Aspartic acid	34.1	33.5	31.9	33.2	32.7	32.2	30.6	31.8	−4.0
Citrulline	9.8	9.4	9.7	9.6	9.7	9.3	9.6	9.6	−0.3
Glutamic acid	62.2	59.4	59.4	60.4	60.6	57.8	57.8	58.7	−2.7
Beta alanine	3.1	2.9	2.9	3.0	3.2	2.9	3.0	3.0	1.4
Threonine	39.0	38.1	43.4	40.2	37.9	37.1	42.2	39.1	−2.8
Alanine	218.7	204.9	229.0	217.5	201.4	188.8	210.9	200.4	−7.9
Gamma amino butyric acid	0.6	0.6	0.6	0.6	0.6	0.6	0.6	0.6	1.4
Proline	85.9	82.3	93.7	87.3	84.1	80.5	91.7	85.5	−2.1
Beta amino butyric acid	0.4	0.3	0.4	0.4	0.3	0.3	0.3	0.3	−11.8
Ornithine	27.6	25.9	22.6	25.4	26.2	24.6	21.5	24.1	−5.1
Alpha amino butyric acid	3.8	3.5	4.1	3.8	3.7	3.5	4.0	3.7	−1.5
Lysine	41.6	37.1	33.9	37.5	40.6	36.2	33.0	36.6	−2.4
Tyrosine	36.9	34.7	37.6	36.4	36.8	34.6	37.5	36.3	−0.3
Methionine	19.3	17.6	15.3	17.4	19.9	18.0	15.5	17.8	2.2
Valine	84.5	82.5	94.4	87.1	82.3	80.4	92.0	84.9	−2.5
Isoleucine	28.9	27.2	33.7	29.9	28.4	26.8	33.1	29.4	−1.7
Leucine	55.1	53.2	62.0	56.8	53.8	51.9	60.6	55.4	−2.3
Phenylalanine	25.6	24.1	28.1	25.9	25.4	23.9	27.8	25.7	−0.8
Tryptophan	19.5	16.3	17.6	17.8	19.3	16.2	17.4	17.7	−1.0