Determination of diazepam in cream biscuits by liquid chromatography.

An analytical procedure was developed for the detection and quantitation of diazepam in cream biscuits, which were used to commit crime. The method involves the extraction of diazepam with ethanol at room temperature, and the extract is filtered, evaporated to dryness, and redissolved in the mobile phase, methanol-acetonitrile-tetrahydrofuran-water (15 + 55 + 4 + 26, v/v). The separation is achieved on a C18 reversed-phase column with the mobile phase and diode array detection (lambda(max)) at 230 nm. Medazepam is used as the internal standard is for quantification. The calibration plot for the determination of diazepam is based on linear regression analysis (y = 0.6687x + 0.0372; r2 = 0.995). The limit of detection for diazepam in the biscuit samples was estimated as 600 ng/mL. The limit of quantitation for diazepam was estimated as 1.75 microg/mL. The diazepam detected per piece of biscuit was found to be in the range of 0.27-0.45 mg. Pure diazepam was added to biscuit samples at 3 levels (100 and 500 microg/g, and 1 mg/g), and the recoveries were found to be 95%. The mean retention time of diazepam was 2.7 min and that of medazepam (IS) was 4 min. The relative standard deviations of the diazepam level in the biscuit samples were estimated to be 0.4% for retention time and 1.02% for peak area in intraday analysis, whereas the corresponding values were and 0.61 and 2.34% in interday analysis. The method is rapid and reliable for qualitative and quantitative analysis of cream biscuits laced with diazepam, and it can be used by law enforcement laboratories for routine analysis.

Application of capillary zone electrophoresis in the separation and determination of the principal gum opium alkaloids.

We describe the use of capillary zone electrophoresis (CZE) for the qualitative and quantitative determination of major alkaloids (i.e., thebaine, codeine, morphine, papavarine and narcotine) in gum opium involving the analysis of alkaloids without derivatization or purification. Three extractions with 2.5% w/v aqueous acetic acid quantitatively extracted major alkaloids. The separation was carried out by CZE using a 7:3 mixture of methanol and sodium acetate (100 mM, pH 3.1) at a potential of 15 kV, with UV detection at 224 nm. Spiking of pure reference alkaloid standards in the opium extract was used for peak identification. The influences of buffer composition, pH and voltage on the separation of alkaloids were studied. The detection limit of each alkaloid dissolved in methanol was found to be 850 ng/mL (morphine), 450 ng/mL (thebaine), 500 ng/mL (codeine), 550 ng/mL (papaverine), and 500 ng/mL (narcotine) at an injection pressure of 300 mbar (injection volume, 4 nL) with a signal-to-noise ratio of 3:1. The external standard method was used for the quantification of alkaloids. The calibration plot was based on linear regression analysis. The relative standard deviation (RSD) for peak area and migration time was in the range of 1.03-3.56% and 0.34-0.69%, respectively. Percentage compositions (g%) of opium alkaloids in five gum opium samples were found to be in the range of 14.45-15.95 (morphine), 2.0-3.45 (codeine), 1.32-2.73 (thebaine), 0.92-2.37 (papavarine), and 3.85-5.77 (narcotine). The method developed is suitable for the routine analysis of major gum opium alkaloids in samples of forensic importance.