The determination of aqueous fluoride by flow injection analysis (FIA) with a helium microwave-induced plasma (He-MIP) is described. This system operates at 500 W and utilizes a modified TM010 resonator cavity with a demountable plasma torch. Both direct nebulization and FIA in conjunction with ultrasonic nebulization (USN) were investigated. FIA was found to be the most reliable method because extended nebulization of aqueous fluoride was found to cause memory effects. Detection limits for aqueous fluoride of 35 and 4 ppm were observed for FIA and direct USN, respectively. The interference effects of pH and selected elements were also studied.

In an effort to determine a practical, efficient, and economical alternative for the use of a radioimmunoassay (RIA) for the detection of lysergic acid diethylamide (LSD) in human urine, the performance of two photometric immunoassays (Dade Behring EMIT II and Microgenics CEDIA) and the Diagnostics Products Corp. (DPC) RIA were compared. Precision, accuracy, and linearity of the 3 assays were determined by testing 60 replicates (10 for RIA) at 5 different concentrations below and above the 500-pg/mL LSD cut-off. The CEDIA and RIA exhibited better accuracy and precision than the EMIT II immunoassay. In contrast, the EMIT II and CEDIA demonstrated superior linearity r2 = 0.9809 and 0.9540, respectively, as compared with the RIA (r2 = 0.9062). The specificity of the three assays was assessed using compounds that have structural and chemical properties similar to LSD, common over-the-counter products, prescription drugs and some of their metabolites, and other drugs of abuse. Of the 144 compounds studied, the EMIT II cross-reacted with twice as many compounds as did the CEDIA and RIA. Specificity was also assessed in 221 forensic human urine specimens that previously screened positive for LSD by the EMIT II assay. Of these, only 11 tested positive by CEDIA, and 3 were positive by RIA. This indicated a comparable specificity performance between CEDIA and RIA. This also was consistent with a previously reported high false-positive rate of EMIT II (low specificity). Each of the immunoassays correctly identified LSD in 23 out of 24 human urine specimens that had previously been found to contain LSD by gas chromatography-mass spectrometry at a cut-off concentration of 200 pg/mL. The CEDIA exhibited superior precision, accuracy, and decreased cross-reactivity to compounds other than LSD as compared with the EMIT II assay and does not necessitate the handling of radioactive materials.

A novel extraction and derivatization procedure for the cocaine metabolite benzoylecgonine (BZE) was developed and evaluated for use in a high-volume forensic urine analysis laboratory. Extractions utilized a Speedisk 48 positive pressure extraction manifold and polymer-based cation-exchange extraction columns. Samples were derivatized by the addition of pentafluoropropionic anhydride and pentafluoropropanol. All analyses were performed in selected ion monitoring mode; ions included m/z 421, 300, 272, 429, and 303 with m/z 421 to 429 ratio used for quantitation. The average extraction efficiency was 80%. Seventy-five common over-the-counter products, including prescription drugs, drug metabolites, and other drugs of abuse, demonstrated no significant interference with respect to chromatography or quantitation. The limit of detection and limit of quantitation were calculated at 12.5 ng/mL, and the assay was linear from 12.5 to 20,000 ng/mL with an r2 of 0.99932. A series of 20 precision samples (100 ng/mL) produced an average response of 97.8 ng/mL and a percent coefficient of variation of 4.1%. A set of 79 archived human urine samples that had previously been found to contain BZE were analyzed by 3 separate laboratories. The results did not differ significantly from prior quantitation or between laboratories. The Speedisk has proven viable for a high-volume production facility reducing overall cost of analysis by decreasing analysis time and minimizing waste production while meeting strict forensic requirements.

The potential for passive cocaine exposure was evaluated in crime laboratory employees preparing training aids for a military working dog program (MWD). The primary goal of the study was to elucidate the routes of exposure and implement procedural changes that would minimize this risk. Several work environments and laboratory procedures were examined by monitoring personal breathing zones (PBZ), ambient airborne cocaine levels in the laboratory spaces, and urinary levels of the primary cocaine metabolite, benzoylecgonine. The study was performed initially using current laboratory procedures to establish a baseline and to identify potential sources of exposure. A subsequent study was performed to determine the effectiveness of the follow-up procedure in reducing exposure. As a result of the changes, the 8-h time weighted averages (TWAs) were 40 to 80% lower in the follow-up study as compared to the baseline assessment. Dermal absorption and PBZ inhalation of cocaine during manufacture were likely the most significant source of cocaine exposure. Ambient airborne cocaine may have also contributed to the total exposure, but for most observations, the concentrations were significantly less than those determined from PBZ monitoring. The maximum ambient cocaine concentration was 0.0144 mg/m(3) compared to a maximum of 0.4004 mg/m(3) observed during PBZ monitoring. Occupational exposure decreased in the follow-up study because of the proper use of personal protective equipment and improvements in engineering controls.

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