OUD	Opioid use disorder
FDA	Food and Drug Administration
BUP	Buprenorphine
MTD	Methadone
NBUP	Norbuprenorphine
BUP-G	Buprenorphine-glucuronide
NBUP-G	Norbuprenorphine-glucuronide
EDDP	2-Ethylidene-1, 5-dimethyl-3,3-diphenylpyrrolidine
EMDP	2-Ethylidene-5-methyl-3,3-diphenylpyrrolidine
LC-MS/MS	Liquid chromatography tandem mass spectrometry
LC	Liquid chromatography
GC	Gas chromatography
CE	Capillary electrophoresis
VH	Vitreous humor
UHPLC-MS/MS	Ultra-high-performance liquid chromatography-tandem mass spectrometry
LLE	Liquid-liquid extraction
SPE	Solid-phase extraction
DLLME	Dispersive liquid-liquid microextraction
GC-MS	Gas chromatographymass spectrometry
NPs	Nanoparticles
MIPs	Molecularly imprinted polymers
Fe3O4@GO-DES	Fe3O4 nanoparticles/graphene oxide/deep eutectic solvent
GC-FID	Gas chromatography-flame ionization detector
PF	Preconcentration factor
UV	Ultraviolet
PAD	Photodiode array detector
FL	Fluorescence
EC	Electrochemical
LDR	Linear dynamic range
LOD	Limit of detection
DMSPE	Dispersive magnetic solid-phase extraction
LOQ	Limit of quantification
LLOQ	Lower limit of quantification
COC	Cocaine
MMT	Methadone maintenance treatment
PpPDA/Fe3O4	Poly para-phenylenediamine modified Fe3O4 NPs
MS/MS	Tandem mass spectrometry
HRMS	High-resolution mass spectrometry
NLX	Naloxone; MTA: Methamphetamine
N6-WT	Nylon 6 modified wooden toothpick
UADLLME	Ultrasound-assisted DLLME
DSS	Dried saliva spots
SHS-HLLME	Switchable hydrophilicity solvent-based homogenous liquid-liquid microextraction
Fe@GO-DES	Magnetic graphene nanoparticles coated with a new deep eutectic solvent
CSDF-ME	Continuous sample drop flow microextraction
UA-SM-SFO-ME	Ultrasonic-assisted supramolecular based on solidification of floating organic drop microextraction
UA-SM-SFO-ME	Ultrasonic-assisted supramolecular based on solidification of floating organic drop microextraction
CS-MNCs	Citrate stabilized magnetic nanocrystals
CPE	Carbonpaste electrode
MWCNT	Multiwalled carbon nanotubes
ELISA	Enzymeimmunoassay
SERS	Surface-enhanced Raman spectroscopy
TRA	Tramadol