Modifier-assisted differential mobility-tandem mass spectrometry method for detection and quantification of amphetamine-type stimulants in urine.
An advantage of differential mobility spectrometry (DMS) is it provides an orthogonal mechanism to mass spectrometry (MS). The DMS-MS/MS detects analytes in the gas phase on the basis of differences in ion mobility in low and high electric fields, which makes DMS-MS/MS an alternative to chromatographic separation-MS. One drawback of DMS is its limited resolution and sensitivity, especially for detecting small molecules when using a nonpolar inert gas as the carrier gas. The present work has evaluated the effects on peak capacity of adding chemical modifiers to inert carrier gases (nitrogen, helium, argon and carbon dioxide). Use of a methanol-helium mixture gave improvements in both separation and sensitivity. Nine structurally similar amphetamine-type stimulants were determined in urine without pretreatment of the samples before analysis. After optimization of carrier gas, nature and concentration of chemical modifier, and DMS temperature, limits of detection ranging from 1.1 to 2.7 ng mL-1, with a linear range of three orders of magnitude (5-5000 ng mL-1) were achieved. Precision was <15% and the accuracy of the quality control samples was 87.6-113.7%. For the quantitation of urine samples from drug abusers, data obtained using DMS-MS/MS showed reasonable agreement (within ±19.5%) with that obtained using LC-MS/MS. The analysis time for DMS-MS/MS was only 1.1 min and a paired sample t-test between the two methods gave a p-value of 0.0894, which indicates that DMS-MS/MS is a reliable method, with comparable precision and sensitivity to LC-MS/MS.
Department and Graduate Institute of Forensic Medicine, College of Medicine, National Taiwan University, Taiwan; Forensic and Clinical Toxicology Center, National Taiwan University College of Medicine and National Taiwan University Hospital, Taiwan. Electronic address: paishanchen@ntu.edu.tw.
Pai-Shan
PS
Chen
Department of Chemistry, Texas A&M University, College Station, TX, USA.
Shu-Hua
SH
Chen
Department and Graduate Institute of Forensic Medicine, College of Medicine, National Taiwan University, Taiwan; Forensic and Clinical Toxicology Center, National Taiwan University College of Medicine and National Taiwan University Hospital, Taiwan.
Jung-Hsuan
JH
Chen
Department and Graduate Institute of Forensic Medicine, College of Medicine, National Taiwan University, Taiwan; Forensic and Clinical Toxicology Center, National Taiwan University College of Medicine and National Taiwan University Hospital, Taiwan.
Wan-Yun
WY
Haung
Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taiwan.
Hsin-Tung
HT
Liu
Department and Graduate Institute of Forensic Medicine, College of Medicine, National Taiwan University, Taiwan.
Po-Hsin
PH
Kong
SCIEX, Taiwan.
Olivia Hsu-Yuan
OH
Yang
D000661:Amphetamine / Q000737:chemistry / Q000302:isolation & purification / Q000652:urine*; D000697:Central Nervous System Stimulants / Q000737:chemistry / Q000302:isolation & purification / Q000652:urine*; D002853:Chromatography, Liquid; D006801:Humans; D000432:Methanol / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013696:Temperature; D016482:Urinalysis / Q000379:methods*
D000697:Central Nervous System Stimulants; D000661:Amphetamine; D009584:Nitrogen; D000432:Methanol
Amphetamine-type stimulants; Differential mobility spectrometry; Drug of abuse; Liquid chromatography; Mass spectrometry; Urine