Rapid Screening of Submicroliter Urine Samples for Drugs of Abuse utilizing Pulsed Gas Ambient Ionization
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.