I will just paste a small clip but I recommend reading the whole study.
Simultaneous Quantification of Methadone
, Cocaine, Opiates, and
Metabolites in Human Placenta by Liquid Chromatography–Mass Spectrometry*
Analytical methods have been developed for different biological matrices from the mother and neonate, including urine (12-14), blood (15,16), oral fluid (17), hair (18,19), sweat (20), meconium (21-24), amniotic fluid, and umbilical cord tissue (25-27).