2-MHA	2-methylhippuric acid
2-PB	2-picoline borane
5-HIAA	5-hydroxyindoleacetic acid
5-HT	5-hydroxytryptamine; serotonine
5-HTrp	5-hydroxytryptophan
AA	ascorbic acid
ACN	acetonitrile
AD	Alzheimer’s Disease
ADHD	Attention-Deficit/Hyperactivity Disorder
AmpD	amperometric detection
APCI	atmospheric pressure chemical ionization
APHD	Huntington’s Disease
APS	amino-propyl silane
AuNPs	gold nanoparticles
BAs	biogenic amines
BDS	base-deactivated silica
CAR/PDMS	carboxen/polydimethylsiloxane
CATs	catecholamines
CE	capillary electrophoresis
CE-AmpD	capillary electrophoresis with amperometric detection
CILE	carbon ionic liquid electrode
CKD	chronic kidney disease
CL	chemiluminescence detection
CNS	central nervous system
COMT	catechol-O-methyltransferase
Cr	creatinine
CSF	cerebrospinal fluid
CSC	carcinoma stem cell sample
CTAB	cetyltrimethylammonium bromide
CZE	capillary zone electrophoresis
DA	dopamine
DAD	diode array detection
DBD-PyNCS	4-(N, N-dimethylaminosulfonyl)-7-(3-isothiocyanatopyrrolidin-1-yl)-2,1,3-benzoxadiazole
DHEAS	dehydroepiandrosterone
DHPG	3,4-dihydroxyphenylglycol
DLLME	dispersive liquid-liquid extraction
DOPAC	3,4-dihydroxyphenylacetic acid
DPE	diphenylethylendiamine
DPSs	dried plasma spots
DUSs	dried urine spots
DVB/CAR/PDMS	divinylbenzene/carboxen/polydimethylsiloxane
E	epinephrine
ED	electrochemical detection
eGFR	glomerular filtration rate
ELISA	enzyme-linked immunosorbent assay
EOF	electroosmotic flow
ESI	electrospray ionization
FA	formic acid
FASI	field amplified sample injection
FASS	field-amplified sample stacking
GABA	γ-aminobutyric acid
GC	gas chromatography
GCE	glass carbon electrode
GC-MS	gas chromatography coupled with mass spectrometry
GC-MS/MS	gas chromatography coupled with tandem mass spectrometry
GC–QqQ-MS	gas chromatography-triple quadrupole mass spectrometry
GITS	non-neural neoplasm gastrointestinal tumor
Glu	glutamate
GR	graphene
HA	hippuric acid
HC	head-column
HE	Hashimoto Encephalopathy
HFBA	4-(heptadecafluorodecyl)benzylamine
HFBCF	1,1,1,2,2,3,3-heptafluorobutyl chloroformate reagent
HILIC	hydrophilic interaction liquid chromatography
HLB	hydrophilic-lipophilic balanced copolymer sorbent
HMDS	hexamethyldisilazane
HMPG sulfate	4-hydroxy-3-methoxyphenylglycol sulfate
HPLC-(ESI)-MS	high-performance liquid chromatography/electrospray ionization mass spectrometry
HPLC-FD	high performance liquid chromatography with fluorescence detection
HPLC-UV	high performance liquid chromatography with ultraviolet detection
HVA	homovanillic acid
IAA	indole-3-acetic acid
ITP	isotachophoresis
LC	liquid chromatography
LC-ESI-MS/MS	liquid chromatography/electrospray ionization tandem mass spectrometry
LC-FL	liquid chromatography with fluorescence detection
LC-MS/MS	liquid chromatography coupled with tandem mass spectrometry
L-DOPA	L-dihydroxyphenylalanine
LEDIF	light emitting diode-induced fluorescence
LIF	laser-induced fluorescence
L-KYN	L-kynurenine
LLE	liquid-liquid extraction
LLME	liquid-liquid microextraction
LLOQ	lower limit of quantification
LOD	limit of detection
LOQ	limit of quantification
L-Tryp	L-tryptophan
L-Tyr	L-Tyrosine
M	metanephrine
MAO	monoamine oxidase
MAOA	monoamineoxidase A
MBHFBA	N-methyl-bis-heptafluorobutyramide
MCE	microchip electrophoresis
MCX	mixed mode cation exchange
MEKC	micellar electrokinetic chromatography
MEPS	microextraction by packed sorbent
MHPG	3-methoxy-4-hydroxyphenylglycol
MIPs	molecularly imprinted polymers
MNs	metanephrines
MNTI	melanotic neuroectodermal tumor of infancy
MRM	multiple reaction monitoring
NA	niacinamide
NBL	neuroblastoma
NE	norepinephrine
NENs	neuroendocrine neoplasms
NETs	neuroendocrine tumors
NM	normetanephrine
OCT	octopamine hydrochloride
PA	polyacrylate
PBA	diphenylborate
PBMC	peripheral blood mononu-clear cells
PCR	polymerase chain reaction
PD	Parkinson’s Disease
PDDA	poly(diallyl dimethylammonium) chloride
PDMS	polydimethylsiloxane
PDMS/DVB	polydimethylsiloxane/divinylbenzene
PEA	phenylethylamine
PEO	polyethylene oxide
PFHA	perfluoroheptanoic acid
PFOEI	2-(perfluorooctyl)ethyl isocyanate
PFUA	perfluoroundecan-1-al
PGC	porous graphitic carbon
PHE	pheochromocytoma
PITC	phenylisothiocyanate
PTSD	post-traumatic stress disorder
RFS	reversed-field stacking
RP18	reversed phase C18 column
SCX	strong cation exchange
SDS	sodium dodecyl sulphate
SPE	solid phase extraction
SPME	solid phase microextraction
SIM	selective ion monitoring
SRM	selective reaction monitoring
TB	tris-borate buffer
TCA	trichloroacetic acid
THF	tetrahydrofuran
THP	tris(3-hydroxypropyl)phosphine
UA	uric acid
UPLC	ultrafast performance liquid chromatography
UV	ultraviolet
UV/Vis	combined ultraviolet and visible radiation detectors,
VMA	vanillymandelic acid
WCX	weak cation exchange