Table 3.

Examples methodologies used for the determination of HNE

Methods	Derivatization	Sample volume	Concentration of HNE ± SD	Linearity	LOD	Precision	Ref.
SPE (Extrelut®)	DNPH	3 mL	Average human plasma 0.65 ± 0.39 μmol/mL	0.1–0.54 μmol/mL	0.1 μmol/mL	2–6%	[87]
HPLC (λ = 370 nm)			Females 0.45 ± 0.23 μmol/mL
SPE-TLC			Males 0.78 ± 0.43 μmol/mL
LC-ESI-MS/MS	5,5′-Dimethyl-1,3-cyclohexanedione	–	Control 0.4 ± 0.1 nmol/mg protein	–	–	–	[73]
			Early Alzheimer’s disease hippocampus/parahippocampal gyrus 1.45 ± 0.5 nmol/mg protein
			Mild cognitive impairment hippocampus/parahippocampal gyrus 1.5 ± 0.3 nmol/mg protein
			Control superior and middle temporal gyrus 0.8 ± 0.1 nmol/mg protein
			Mild cognitive impairment superior and middle temporal gyrus 2.4 ± 0.3 nmol/mg protein
			Early Alzheimer’s disease superior and middle temporal gyrus 2.9 ± 0.3 nmol/mg protein
			Control cerebellum 0.8 ± 0.1 nmol/mg protein
			Late-stage Alzheimer’s disease mild cognitive impairment 1.5 ± 0.2 nmol/mg protein
ESI-MS	Apomyoglobin	–	–	–	–	–	[82]
HPLC fluorescence detection (λ = 380 nm and emission λ = 445 nm)	1,3-Cyclohexanedione	1 mL plasma	LA 45.31 ± 16.86 nmol/mL	–	–	–	[29]
			Control 11.24 ± 2.19 nmol/mL
GC-negative-ion chemical ionization-MS	O-Pentafluorobenzyl oxime	250 μL plasma or CSF	Control 0.66 ± 0.06 nmol/mL	1–100 ng/mL		–	[88]
			HIV 0.81 ± 0.07 nmol/mL
			AIDS 1.24 ± 0.18 nmol/mL
			Parkinson’s disease
			CSF 0.20–3.14 nmol/mL
			Plasma 0.71–6.03 nmol/mL