Liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) analysis provides an expansive technique for identifying many known and unknown analytes. This study developed a screening method that utilizes automated solid-phase extraction to purify a wide array of analytes involving stimulants, benzodiazepines, opiates, muscle relaxants, hypnotics, antihistamines, antidepressants and newer synthetic "Spice/K2" cannabinoids and cathinone "bath salt" designer drugs. The extract was applied to LC-TOF-MS analysis, implementing a 13 min chromatography gradient with mobile phases of ammonium formate and methanol using positive mode electrospray. Several common drugs and metabolites can share the same mass and chemical formula among unrelated compounds, but they are structurally different. In this method, the LC-TOF-MS was able to resolve many isobaric compounds by accurate mass correlation within 15 ppm mass units and a narrow retention time interval of less than 10 s of separation. Drug recovery yields varied among spiked compounds, but resulted in overall robust area counts to deliver an average match score of 86 when compared to the retention time and mass of authentic standards. In summary, this method represents a rapid, enhanced screen for blood and urine specimens in postmortem, driving under the influence, and drug facilitated sexual assault forensic toxicology casework.
The objective of this research was to determine the concentrations and distribution of the atypical antipsychotic drug, quetiapine, in postmortem tissues from eight Medical Examiner cases. Quetiapine was isolated from liquid specimens and tissue homogenates by extraction at an alkaline pH into 1-chlorobutane. The 1-chlorobutane was decanted, and quetiapine, plus the internal standard (prochlorperazine), was back-extracted into 0.1N sulfuric acid. The acid layer was made basic, and quetiapine, plus the internal standard, was re-extracted into 1-chlorobutane. Quantitation was by gradient, high-pressure liquid chromatography on a C-8 ODS (2.1 x 150 mm, 5 mu) column with acetonitrile/0.1M ammonium hydroxide (pH 10) mobile phase and a photodiode array detector set at 258 nm. The apparent linear range of the assay was from 0.05 to 5.0 microg/mL. At known concentrations of 0.1 and 0.5, interday accuracy (n = 5) was 103.8 and 107.2%, respectively. Interday precision (% cv) at the same concentrations was 9.8 and 9.0, respectively. In the cases where quetiapine was not considered to have contributed to the death, the postmortem concentrations in blood, liver, and bile ranged between 0.15 and 2.7 mg/L (n = 6), 1.3 and 9.5 mg/kg (n = 8), and 10 and 46 mg/L (n = 5), respectively. In the one case involving a quetiapine overdose, concentrations in blood (19.8 mg/L), liver (12.6 mg/kg), and bile (161 mg/L) exceeded the ranges of concentrations determined in specimens from the quetiapine-unrelated deaths.
The high prevalence of alprazolam abuse translates to an increased workload for crime laboratories in characterizing seized tablets. These tablets may originate as diverted pharmaceuticals or counterfeited mimics, so efficient analytical techniques should provide confirmatory data while minimizing destruction of evidence. We offer the first report of a validated forensic method for confirming alprazolam tablets by direct analysis in real time-time of flight (DART-TOF) mass spectrometric analysis. This technique provides rapid identification of target analytes with minimal sample preparation, allowing direct analysis in the atmospheric sample gap. Selectivity is achieved through high resolution and mass accuracy, unique ion fragments, and chlorine isotopic ratios. This method utilizes fragmentation in two separate voltage functions to observe the alprazolam pseudo molecular ion at 309.09070 using 40 V and major ion fragments of 281.07197 and 205.07657 at 120 V. These parameters allow our laboratory to confirm alprazolam tablets efficiently, without compromising quality forensic standards.
Topimarate (Topamax) is a novel antiepileptic drug. Its mode of action is multifactorial and involves blockage of voltage-dependent sodium channels. The drug was detected in a 15-year-old epileptic who died soon after switching seizure prescriptions. Topimarate was recovered by basic extraction with ethyl acetate and analyzed by gas chromatography-mass spectrometry using selected ion monitoring. Ions monitored were m/z 324 and m/z 110 for topiramate and m/z 98 for the internal standard mepivacane. The drug was quantitated in blood, vitreous humor, bile, stomach content, and liver: the concentrations were 8.9, 12.4, and 10.9 mg/L, 31 mg/total content, and 29 mg/kg, respectively. Topiramate was detected in urine but not quantitated. Other drugs identified in this case were 0.45 mg/L nordiazepam and 0.05 mg/L oxazepam in blood. No alcohol was detected in any of the specimens. The cause of death was seizure disorder with upper respiratory infection. The manner of death was determined as natural. To our knowledge, this is the first report of the presence of topiramate in postmortem specimens.
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