Table 2.

Identified reference molecules included in the composition of IR spectra of tested human sera.

Molecule	Absorpcion band (cm−1)	ID	Description	Component group	References
CRP	1545	[B1]	N–H in plane bending vibration strongly coupled to C–N stretching vibration protein	Amide II	63
	1632–1652		NH2 scissoring	Amide I
Homocysteine	1600–1550	[B2]	NH2 scissoring	Amide I	12
			N–H in plane bending vibration strongly coupled to C–N stretching vibration protein	Amide II
LDL	1740–1720	[B3]	C=O stretching	Amide I	66
	1660–1600		C=O symmetric stretching	Amide I
			NH2 scissoring	Amide I
TNF-α	1650	[B4]	C=O stretching	Amide I	68
	1760–1740
Triglycerides	2925–2850	[B5]	Methylene asymmetric stretching	Lipids	51
	1740		C=O stretching	Amide I
	1475–1470		Methylene scissoring
	1460–1440		Methyl asymmetric deformation	Amino acid
	1385		Methyl symmetric deformation	Amino acid
	1180		C–O symmetric stretching	Carbohydrates
	1115		C–O symmetric stretching	Carbohydrates

ID symbol shows representative characteristic fragment of infrared spectrum, of human serum, for the molecules differentiating the study groups presented on Fig. 1a,b: patients with coronary heart disease (CHD) infected with H. pylori, healthy donors non-infected or infected with H. pylori. B band, CRP C-reactive protein, LDL low density lipoprotein, TNF-α tumor necrosis factor alpha.