By means of thin-layer chromatography, an unidentified alkaloidal fraction was observed in illicit cocaine. Because of its persisting presence, efforts were undertaken to isolate and identify this fraction. Various analytical techniques showed complex results, finally pointing to the possibility of isomerization of constituents of the fraction. A direct-probe mass spectrum showed a fragmentation pattern which could only fit a truxilline. When using thin-layer chromatography, at least five isomers could be observed. This is the first time truxillines have been observed, isolated, and identified by thin-layer chromatography.
The use of Bond Elut Certify columns for the isolation of morphine from whole blood was evaluated. In order to monitor possible losses and the elution profile of morphine, a small amount of the tritiated analogue was added to the samples. Four sample pretreatment methods, three protein precipitation methods and one sonication/dilution method, were tested. The latter one gave the best results. The blood sample was applied onto the column at pH 3.3 after sonication and dilution with 0.1 M phosphate buffer (pH 3.3). The retention of morphine was affected by the pH of the samples, and the loss of morphine during sample application was minimized at low pH (3.3). The interferences were removed by washing the column with the phosphate buffer, 0.01 M acetic acid (pH 3.3), and methanol, sequentially. Ammoniated methanol, 2 mL at 2%, was selected to elute morphine. As a result, more than 80% of 3H-morphine was recovered for concentrations of morphine ranging from 5 to 4000 ng/mL.
Broad-spectrum drug screening requires that all relevant substances be isolated, detected, and identified, regardless of their structure and/or polarity. To this end, systematic solid-phase extraction (SPE) approaches for drug isolation from biological fluids are required. Because speed and cost effectiveness are key issues in analytical toxicology, we have evaluated a disc-format extraction device for this purpose and compared the latter with an existing packed-bed column-format method. The discs were SPEC.PLUS.C18AR/MP3 cartridges with 10-mL solvent reservoirs, providing hydrophobic and cation exchange interactions. Blank human urine was spiked at 2 microg/mL with a selection of acidic, neutral, and basic drugs representing a variety of relevant drug classes. Urine specimens (2 mL) were diluted with 2 mL 0.1 M phosphate buffer (pH 5.0) and then applied to the preconditioned disc. Washing was done with 1 mL water. Acidic and neutral drugs were eluted with 1 mL ethyl acetate/acetone (1:1), and basic drugs were eluted with 1 mL ammoniated ethyl acetate. The eluates were collected separately, evaporated down to about 0.1 mL, and analyzed by gas chromatography-flame-ionization detection to check cleanliness, recoveries, and reproducibilities. The discs showed good extraction properties for all drugs and were easy to handle. Recoveries were 75-100% with coefficients of variation of around 5%. The resulting eluates showed only a few matrix interferences. As compared to our standard SPE method with packed-bed columns, the disc procedure allowed reductions in elution volumes and total processing time of approximately 60-65%.
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