RESUMO
Kratom is an herbal drug that is legal in the USA. While it is marketed as a safer alternative to opioids, it can cause opioid-like withdrawal symptoms when discontinued after regular use. Several case studies have shown that kratom exposure in utero can lead to symptoms in newborns consistent with neonatal abstinence syndrome. Here, we present a validated method for the detection of kratom in umbilical cord by liquid chromatography--tandem mass spectrometry. The umbilical cord is homogenized in solvent and kratom analytes are purified by solid phase extraction (strong cation exchange). Diastereomeric kratom alkaloids mitragynine (MG), speciociliatine (SC), speciogynine and mitraciliatine are separated by reverse phase chromatography on a phenyl-hexyl column. Applying this method to residual umbilical cords submitted to our laboratory for drug testing, 29 positive specimens exhibiting varied kratom analyte distributions were observed. MG and SC were the most abundant kratom analytes and were selected as biomarkers of kratom exposure. A cutoff concentration of 0.08 ng/g was established for both MG and SC.
