Development of an LC-MS/MS method for determining 5-MeO-DIPT in dried urine spots and application to forensic cases.
Xiuying Yan, Shuai Yuan, Zhiguo Yu, Yunli Zhao, Sujing Zhang, Hejian Wu, Hui Yan, Ping Xiang
Journal of forensic and legal medicine May 1, 2020 DOI: 10.1016/j.jflm.2020.101963 via PubMed
Summary
A dried urine spot (DUS) method using LC-MS/MS was developed to measure the tryptamine hallucinogen 5-MeO-DIPT, which is unstable in liquid urine. Ten microliters of urine were spotted on a card and extracted with methanol. The method's limit of detection was 0.1 ng/ml and lower limit of quantification was 0.2 ng/ml, with accuracy between 98.2% and 103.9% and precision between 2.7% and 8.5%. 5-MeO-DIPT was more stable in DUS than in urine stored at 25 °C. When applied to urine from known users, concentrations ranged from 0.3 to 2.3 ng/ml, lower than those measured by GC-Orbitrap-MS. The small sample volume and simplicity make this useful for drug screening.
Study at a glance
| Characteristics | Method development and validation Peer reviewed |
|---|---|
| Population | Individuals known to have used 5-MeO-DIPT |
| Keywords | 5-MEO-Dipt Dried urine spots Drug abuse Lc-ms/ms Monitoring |
| Key finding | 5-MeO-DIPT was more stable in dried urine spots than in liquid urine at 25 °C, and the method detected concentrations of 0.3-2.3 ng/ml in users' urine. |
Abstract
The dried urine spots (DUSs) technique is increasing continuously as an easy sampling method for monitoring substance abuse due to its advantages of stability and convenience regarding transport and storage. 5-Methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) is a new type of tryptamine hallucinogen, the use of which has been banned in many countries. And according to the previous research, 5-MeO-DIPT is not stable in urine. In order to improve its stability, an LC-MS/MS method for determining 5-MeO-DIPT in DUSs was developed. 10 μl urine was spotted on Whatman FTATM classic card, then extracted with 200 μl methanol, and liquid chromatography-tandem mass spectrometry in positive ion multiple reaction monitoring mode was utilized for analysis. The LOD and LLOQ of the method were 0.1 ng/ml and 0.2 ng/ml, respectively. The accuracy and precision were 98.2%-103.9% and 2.7%-8.5%, respectively. It was found that the stability of 5-MeO-DIPT in DUSs was better than the stability of 5-MeO-DIPT in urine stored at 25 °C. Moreover, this method was also applied to detect 5-MeO-DIPT in the urine of individuals known to have used 5-MeO-DIPT. It was found that the concentrations of 5-MeO-DIPT were 0.3-2.3 ng/ml, which were lower than those obtained via GC-Orbitrap-MS. The small volume of urine required (10 μl), combined with the simplicity of the analytical technique, makes this an useful procedure for the screening of drug of abuse.