Development and validation of a LC/MS method for the determination of Δ(9)-tetrahydrocannabinol and 11-carboxy-Δ(9)-tetrahydrocannabinol in the larvae of the blowfly Lucilia sericata: Forensic applications.

In a number of forensic toxicological cases, Δ(9)-tetrahydrocannabinol (THC) and its metabolite 11-carboxy-delta-9-tetrahydrocannabinol (THCA) are frequently considered as contributor factors to the event. To that, a liquid chromatographic mass spectrometric method is described for the identification and quantitation of THC and its metabolite THCA in the forensically important larvae of L. sericata. Larvae of Lucilia sericata were fortified with varying concentrations of THC and THCA covering the calibration range between 10 and 500pg/mg. For the isolation of the analytes from larvae, several extraction techniques were evaluated and finally liquid-liquid extraction under acidic pH was selected using hexane-ethyl acetate (50:50, v/v) as extraction solvent. For the chromatographic separation, a Waters Symmetry® C18 analytical column was used while the mobile phase was acetonitrile-ammonium acetate (2mM) (30:70, v/v). The detection was performed using electrospray ionization source in negative mode (ESI-) and the selected ions monitored were m/z 313 for THC and m/z 343 for THCA. The proposed method which is simple and sufficiently sensitive for the detection of THC and THCA even in a single larva sampling, assisted the investigation of a forensic case.

Direct urine analysis for the identification and quantification of selected benzodiazepines for toxicology screening.

A simple and rapid LC/MS method with direct injection analysis was developed and validated for the identification and quantification of ten benzodiazepines (flunitrazepam, nordiazepam, diazepam, 7-aminoflunitrazepam, flurazepam, bromazepam, midazolam, alprazolam, temazepam and oxazepam) in human urine using diazepam-d5 as internal standard (IS). The main advantage of the proposed methodology is the minimal sample preparation procedure, as diluted urine samples were directly injected into LC/MS system. Electrospray ionization in positive mode using selected ion monitoring was chosen for the identification and quantification of the analytes. The linear range was 50-1000 ng/mL for each analyte, with square correlation coefficient (r(2))≥0.981. Interday and intraday errors were found to be ≤5.72%. The LC/MS method was applied at ten real samples found initially to be positive and negative, using immunoassay technique. Finally the results were confirmed with GC/MS. The method demonstrates simplicity and fast sample preparation, accuracy and specificity of the analytes which make it suitable for replacement of immunoassay screening in urine avoiding thus false negative/false positive results. Using this method, laboratories may overcome the problem of high cost instrumentation such as LC-MS/MS by providing similar sensitivity and specificity with other methods.

Migration study of 1,3-butadiene in eye-drop solutions.

The potential deleterious effects of extractables/leachables in pharmaceutical products led the USP, EP, and JP to require extractable and toxicity testing of container/closure systems. To that, a headspace gas chromatography flame ionization detection method was developed and validated for the determination of 1,3-butadiene (1,3-BD) as a potential extractable residue from a pharmaceutical container/closure system into eye-drop solutions. A migration study was further applied in eight eye-drop solutions (currently marketed products) after short- and long-term exposure of these products at various temperatures. This method allows the establishment of safety-qualification thresholds for 1,3-BD being capable of monitoring eye-drop solution products for this residue.