Determination of 5-MeO-DIPT in Human Urine Using Gas Chromatography Coupled with High-Resolution Orbitrap Mass Spectrometry

A method using gas chromatography high-resolution mass spectrometry was developed to detect and measure the designer hallucinogen 5-MeO-DIPT in urine. Two metabolites, 5-OH-DIPT and 5-MeO-IPT, were identified in users' urine. The method accurately quantified 5-MeO-DIPT between 2 and 300 ng/mL, with a detection limit of 1 ng/mL. In drug abusers, urine concentrations ranged from 1 to 2.8 ng/mL. Stability testing showed that 5-MeO-DIPT concentration decreased by 22.8% after 24 hours at 25°C, 33.2% after 5 days at 4°C, and 38.2% after 7 days at 4°C, but was stable for 30 days at -20°C. Freezing urine samples is recommended for accurate analysis.

Study at a glance

Abstract

5-Methoxy-N,N-Diisopropyltryptamine (5-MeO-DIPT) is a designer hallucinogen derived from tryptamine and its use has been banned by many countries. In this study, a qualitative and quantitative method was developed for determining 5-MeO-DIPT in urine by gas chromatography high-resolution mass spectrometry. 5-hydroxy-N,N-diisopropyltryptamine (5-OH-DIPT) and 5-methoxy-N-isopropyltryptamine (5-MeO-IPT) were identified as 5-MeO-DIPT metabolites in abusers' urine. 5-MeO-DIPT was extracted from urine by liquid-liquid extraction with ethyl acetate under alkaline conditions. The extract was analyzed by GC-Orbitrap-MS in full scan mode with a resolution of 60,000 full width at half maxima (FWHM). The linear range of this method was 2-300 ng/mL with r > 0.99, and the limit of detection was 1 ng/mL. The accuracy and precision were 93-108.7% and 3.1-10.3%, respectively. This method is simple and sensitive. It has been successfully used to detect 5-MeO-DIPT in drug abusers' urine, which showed that the concentrations of 5-MeO-DIPT were between 1 and 2.8 ng/mL. 5-OH-DIPT and 5-MeO-IPT, two urinary major metabolites of 5-MeO-DIPT, were identified in urine samples from 5-MeO-DIPT users. Furthermore, the stability of 5-MeO-DIPT in human urine was investigated. It was discovered that the concentration of 5-MeO-DIPT in urine decreased by 22.8, 33.2 and 38.2% after samples were stored for 24 h at 25°C, 5 days at 4°C and 7 days at 4°C, respectively. And 5-MeO-DIPT in urine were stable after they were stored for 30 days at -20°C. Therefore, it is recommended that urine should be stored under freezing conditions before performing 5-MeO-DIPT analysis.