Benzodiazepines (BDZs) are widely used as tranquilizers and anti-depressive drugs in common clinical practice. However, their ready availability and their synergistic effects with alcohol make them attractive for criminal intentions. To prove criminal action for legal reasons, it is often necessary to analyze beverage residues from a crime scene. Milk-based alcoholic drinks (whiskey creams) are gaining popularity due to their lower alcohol content pleasant taste. However, the complexity of this sample, containing proteins and fatty acids, can mask the presence of drugs or other substances in standard analysis methods. These characteristics make whiskey creams highly suitable for illicit purposes. In this study, eight BDZs, including diazepam, chlordiazepoxide, clobazam, flunitrazepam, bromazepam, flurazepam, nitrazepam and clonazepam, were extracted from whiskey cream using the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method and analyzed using GC-MS. The QuEChERS protocol can efficiently separate most of the matrix from the target compounds while maintaining acceptable recoveries. The presented method is simple and rapid and has been validated in terms of precision, accuracy and recoveries. Limits of detection and limits of quantitation were in the range of 0.02-0.1 and 0.1-0.5 µg/mL, respectively. Whiskey cream beverages, fortified with commercial drugs at 20 µg/mL, were extracted and analyzed demonstrating the applicability of the method in forensic analysis.
An LC-MS method for the analysis of personal care and household products without sample preparation is presented. The method takes advantage of the Direct-electron ionization (EI) LC-MS interface for the quantitation of principal components, as well as for the identification of unknown or undeclared ingredients. The technique has proven its inertness toward matrix effects and the electron ionization allows quantitation and library identification. Commercially available products (shower gel, perfume, and hand cream) were diluted with methanol and injected directly into a nano-LC column. Limonene, linalool, and citral were selected as target compounds because of their use as fragrances in toiletry and detergent products. These and all other fragrances are commonly determined with GC-MS analysis, prior to sample cleanup, a procedure that can lead to analytes loss. The selected compounds are not detected with ESI because of their poor or very low response. Figures of merit and validation studies were executed and special attention was devoted to matrix-effects evaluation, because a sample preparation procedure is not involved. No matrix effects were observed, and the repeatability was excellent even after several weeks of operation. Products composition was investigated in full scan mode to determine the presence of unknown or not listed ingredients.
We investigated the effect of temperature on the packing procedure of nano-LC columns (up to 50 cm) and on their performance. Several slurries of stationary phase were prepared using different solvent mixtures. Their stability was evaluated at several temperatures: 70°C, 50°C, and room temperature. At the higher temperature (70°C) the suspensions resulted to be stable for a longer time. For each slurry, we compared nano-LC columns packed with ultrasounds at 70°C and at room temperature. All the columns were tested with a standard mixture at 70°C, to reduce the solvent viscosity and the backpressure. Main chromatographic parameters such as the asymmetry factor, As, the reduced plate high, h, pattern in a Van Deemter plot, the total porosity, ε(t), and the permeability, k, were calculated and discussed. One of the nano-LC columns was used to separate a mixture of pesticides in a LC-MS system with an electron ionization LC-MS interface (Direct-EI). From our knowledge, this is the first study on the role of temperature in the efficiency of slurry-packing procedure.
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