Rapid Screening of Submicroliter Urine Samples for Drugs of Abuse utilizing Pulsed Gas Ambient Ionization
Brian D Musselman1, Christopher Esposito2, Francois Espourteille2, William Fatigante1, Celia Peterson1, John H Moncur3 and Scott J Campbell3
1IonSense, Inc., Saugus, MA; 2Comprehensive LCMS Solution Inc., Lakeville, MA and 3SpectralWorks Limited, Runcorn, UK.
First presented at BMSS AIEFASIG Meeting University of Surrey. April 2022
Rapid detection of trace drugs-of-abuse in urine is demonstrated using a pulsed gas direct analysis in real time ambient ionization equipped time-of-flight mass spectrometer. Submicroliter sampling combined with analysis at multiple temperatures serve to minimize the matrix effects normally encountered in direct analysis of urine without pre-processing to remove salts, proteins, metabolic products including creatinine and urea. Accurate control of the temperature of ionization exiting the DART source and limiting thermal desorption time to one second per sample serve to permit rapid sensitive detection of drugs-of-abuse. Addition of isotopically labelled reference standards and their ionization serve to provide semi-quantitative determination for those drugs detected making the method suitable for high throughput screening of raw urine.
Analysis of urine samples presented in 96-well SBS format plates were completed by sampling using a 12-pin replicator (VP Scientific) with the 45-micron diameter pins serving as both sample collector and desorption support. The replicator was mounted on the linear rail presentation system of a JumpShot DART-MS to permit automated presentation of each sample (Figure 1).
The release of a one second pulse of heated ionizing gas from the DART source was coordinated with the introduction of each sample into the desorption ionization region. Ion detection was completed using a JEOL AccuTOF-DART high-resolution time-of-flight MS with DART gas temperature of 350C (Figure 2).
Analysis of Urines spiked with DOA standards
100μl of Urine including untreated and those spiked with varying concentrations of DOA’s were sequentially. DART-MS results for detection of Methadone are shown in Figure 3.
High-Throughput Screening for Drugs: Higher Resolution or MSMS required – Detection of EDDP [M+H]+
Detection of ions from background observed in mass chronograms of 10ppm mass windows (left) and easily observed in the partial mass spectrum. Despite background some drugs are detectable down to their cut-off concentration (below).
Pulsed ion MS/MS results for detection of readily detectable EDDP (above right) and Norfentanyl which requires MS/MS (below right) as measured.
• The 24-Pin Sampler with DART-MS analysis permits rapid detection and quantitative analysis of some drugs-of-abuse using high resolution mass spectrometers.
• No sample preparation is required as the narrow metal pins collect only a small volume of urine from either 96- or 384-well plates facilitating ultrahigh speed analysis at very low cost per sample.
• Utilization of higher resolution and MS/MS methods are underway in order to increase the number of DOA’s detectable.
• Method has potential for screening of >1000 samples per hour with no solvent or chromatographic materials.
DART-MSMS completed with Agilent Ultiva courtesy of Joan Zou, and Nandhini Sokkalingam, MassWerk, Inc.