Direct quantification of cocaine in urine by time-of-flight mass spectrometry

The direct quantification of cocaine in urine has been achieved using time-of-flight secondary-ion mass spectrometry (TOF-SIMS). The dynamic range of the TOF-SIMS is four orders of magnitude using one internal standard concentration. The limit of detection (LOD) and limit of quantification (LOQ) have been determined to be 3 ng/mL and 10 ng/mL, respectively, for MeOH standards; the LOD and LOQ have been 33 ng/mL and 100 ng/mL, respectively, in urine samples. Coefficients of variation have ranged from 0.7 to 2.7 for the MeOH standards and 2.5 to 8.0 for the urine samples. The use of TOF-SIMS to simultaneously detect multiple drugs in urine is also demonstrated. The advantages and disadvantages of directly quantifying drugs in urine are discussed. Practical considerations regarding the use of matrix-assisted laser desorption/ionization mass spectrometry for multi-component analysis are also presented.