Abstract: Two solution were prepared for filling the two drive syringes of the stopped-flow module. One contained 10 µL of urine and an appropriate volume of the fluorescein-labelled analyte in buffer in a final volume of 0.5 mL. The other contained an appropriate volume of the antibody in 0.5 mL of buffer. Portions (40 µL) of the two solution were transferred to the mixing chamber at 20 ml/s. The time course of the fluorescence intensity was measured in the two emission channels at 550 nm (excitation at 494 nm). The stopped-flow module was computer-controlled and the initial reaction rate was determined in 5-10 s. The procedure was exemplified by the determination of amphetamine and of the metabolites benzoylecgonine and 11-nor-Δ8-tetrahydrocannabinol-9-carboxylic acid. Calibration graphs for these three were 20-300, 15-300 and 10^-400 µg/l respectively, with detection limits of 7, 5 and 3 µL/l, 3-12 times lower than by conventional fluorescence polarization immunoassay. The new method was also more precise (RSD of 1.4-3.6%, vs. 2.2-7.4%) and recovery was close to 100%. The correlation between the two methods was excellent (r > 0.99).

Abstract: Cocaine (I) was determined Standard Reference Material 1508 (freeze-dried human urine) by GC - MS and HPLC methods and benzoylecgonine (II) was determined by GC - MS and FIA - thermospray MS (details given). Concentrations were determined for three levels of I and three levels of II. After one year, the concentration. of I and II were determined again by GC - MS in order to investigate the stability of the standard; results showed no indication of any decomposition having occured. The precision of the measurements show that material is suitable for use as a control material and as an accuracy benchmark for the drug testing community. The concentrations of cocaine and benzoylecgonine (BE) in Standard Reference Material (SRM) 1508, cocaine and metabolites in freeze-dried human urine, were determined at the National Institute of Standards and Technology (NIST, formerly NBS) by two independent methods. For cocaine, one method was based on gas chromatography/mass spectrometry (GC/MS); the other was based on high performance liquid chromatography (HPLC). For BE, one method was based on GC/MS; the other was based on flow injection analysis/thermospray mass spectrometry (FIA/MS). The results for each pair of methods were statistically evaluated. Concentrations were determined in the SRM for three levels of cocaine and three levels of benzoylecgonine. Methylecgonine, although present in the material, was not determined. For cocaine, the concentrations were 90, 263, and 429 ng/mL of human urine. For BE, the concentrations were 103, 259, and 510 ng/mL of human urine.

Abstract: A fast anal. approach for the simultaneous quant. screening for illicit drugs in serum and urine without tedious chromatography separation steps was developed by combining solid phase extraction (SPE) followed by flow injection analysis (FIA) with ion spray-ionization and tandem mass spectrometry (MS-MS) detection using a PE Sciex API 300 triple-quadrupole MS. MS-MS anal. was performed by sequentially isolating the precursor ions of the analytes and their deuterated standards with subsequent fragmentation and monitoring of one fragment ion for each substance. A multiple-reaction monitoring experiment was set up for morphine (MO), codeine (COD), amphetamine (AMP), benzoylecgonine (BZE), and their deuterated analogs. For method evaluation, serum samples spiked with 2-1000 ng of each drug and deuterated standards were extd. by mixed-mode SPE, redissolved in MeCN-NH4OAc-buffer, and directly injected by flow injection into the ion spray source. The specificity of this new method was demonstrated by testing compounds with similar chemical structure for interferences from the analytes of interest (e.g., hydromorphone, morphine glucuronide, and 6-monoacetylmorphine with MO; dihydrocodeine and hydrocodone with COD; cocaine [COC] and ecgonine methylester with BZE; methamphetamine with AMP). The possibility of interferences of such compounds with the FIA-ion spray-MS-MS screening method is discussed. Spiked serum samples and serum and urine samples from drug addicts and victims of drug abuse were analyzed with FIA-MS-MS and, after derivatization, with gas chromatography-mass spectrometry (GC-MS). Comparable quant. results were obtained with both methods; no interferences with metabolites or other compounds were found. The FIA-ionspray-MS-MS method is a fast, quant., sensitive, and highly specific alternative method to drug-screening by immunoassays, high-performance liquid chromatography, and GC-MS. It can be used for the simultaneous detection of different drugs and metabolites such as opiates, COC, AMP derivatives, and many other drugs.