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The Nathan S. Kline Institute for Psychiatric Research

Analytical Psychopharmacology


Xie Lab

Lab Name
Head of Lab
Research Scientist

Research in the Xie Mass Spectroscopy Lab is focused on the development and application of analytical methods by GC-MS and LC-MS for the quantitative determination of drugs and endogenous compounds of interest in psychiatric research.


Gas chromatography–mass spectrometry (GC-MS) and Liquid chromatography–mass spectrometry (LC-MS) are widely used to identify and measure drugs and endogenous compounds of interest in the samples for psychiatric research. Our group has developed new assays for psychotropic drugs and their metabolites with very high specificity and sensitivity. We have utilized these methods in quantitative measurements for hundreds plasma, urine, brain tissues, saliva and cerebrospinal fluid samples each year. In recent years, we have quantitatively assayed THC, nor-carboxy-THC, amphetamine, GABA, gabapentin, lofexidine, quinolinic acid in plasma, and tetrahydrocannabivarin, tetrahydrocannabivarin carboxylic acid in urine samples by GC-MS. We also have used LC-MS to measure oxycodone, cocaine and its metabolites, nicotine, cotinine in plasma, cannabidiol in urine, and anandamide and 2-Arachidonoylglycerol in brain tissues. In addition, we have carried out dose analysis of THC and cocaine by LC-MS procedures.

Current Investigations

We are working on developing a LC-MS method for the measurement of GABA in plasma samples, which will simplify the GC-MS procedure for the compound we are using. We also are aiming to reach higher sensitivity with 100 pico gram for the measurement of amphetamine in fly brain tissues by GC-MS.