Automatic MDSPE Combined with DART-HRMS for the Rapid Quantitation of 21 Synthetic Cathinones in Urine.

A new, rapid, and automated method for the quantitation of 21 synthetic cathinones in urine was established using magnetic dispersive solid-phase extraction (MDSPE) in combination with direct analysis in real time-high-resolution mass spectrometry (DART-HRMS). Sample preparation and quantitation were verified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methcathinone-D3, α-PVP-D8, and proadifen (SKF525A) were used as internal standards. Magnetic HLB extractant and NaH2PO4/NaOH buffer (0.2 M, pH 7) were used in automatic MDSPE. All 21 synthetic cathinones could be detected and analyzed by DART-HRMS in under 1 min. It was proven that the linearities of 21 synthetic cathinones were suitable (R2 > 0.99) in the concentration ranges of 0.5-100 ng/mL or 1-100 ng/mL. The precision and accuracy values were all within ±15%, and the samples were stable under various conditions. The average time of each sample from preprocessing to completion of detection was approximately 2 min, allowing for rapid sample analysis. The relative error (RE) of the concentrations obtained by DART-HRMS and LC-MS/MS were within ±13.61%, and the linear coefficient (R) was 0.9964. The results of DART-HRMS and LC-MS/MS provided equivalent values at the 95% confidence level. In summary, a simple, fast, and convenient quantitation method via DART-HRMS was established. This application can be utilized to reduce backlogs and promote rapid case processing.

Simultaneous separation and determination of 32 fentanyl-related substances, including seven sets of isomeric fentanyl analogues, by ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry.

A method for separation and determination of 32 fentanyl-related substances, including seven sets of isomeric fentanyl analogues, was developed using ultra-high-performance liquid chromatography coupled with quadrupole-orbitrap high-resolution mass spectrometry. The collision energy, chromatographic column, and mobile phase were optimized. All compounds were efficiently flushed out of a universal C18 column with a soft gradient consisting of solvent A (2 mM ammonium formate and 0.1% formic acid in water) and solvent B (2 mM ammonium formate and 0.1% formic acid in methanol) in only 20 min, achieving excellent resolution. Detection and analysis were carried out simultaneously in the positive ion mode using the full scan and data-dependent tandem mass spectrometry modes with a normalized collision energy of 40. The method was validated in terms of limit of detection, limit of quantification, linearity, accuracy, and precision. For all fentanyl-related substances, the limit of detection (0.5 ng/mL) and limit of quantification (1 ng/mL) were adequate for screening and quantification in daily drug control. Calibration curves for all compounds were established in the range of 1-500 ng/mL. The intra- and interday precision (RSD%) were within 0.4-2.3 and 0.7-2.7%, respectively. The accuracy ranged from 99 to 106%. The method was applied to analyze seized drug samples.

Comparison of the Detection Windows of Heroin Metabolites in Human Urine Using Online SPE and LC-MS/MS: Importance of Morphine-3-Glucuronide.

Heroin abuse is a serious problem that endangers human health and affects social stability. Though often being used as confirmation of heroin use, 6-monoacetylmorphine (6-MAM) has limitations due to its short detection window. To compare the detection windows of heroin metabolites (morphine (MOR), 6-MAM, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G)) in human urine, an automated online solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated. The limits of detections (LODs) of the four metabolites were in the range of 1.25-5 ng/mL. Intra and inter-day precision for all the metabolites was 0.4-6.7% and 1.8-7.3%, respectively. Accuracy ranged from 92.9 to 101.7%. This method was then applied to the analysis of urine samples of 20 male heroin abusers. M3G was detected 9-11 days after admission to the drug rehabilitation institute in 40% of heroin users while MOR or M6G was not always detected. The detection window of M3G was thus the longest. Furthermore, M3G had a much higher concentration than MOR and M6G. Therefore, M3G could provide diagnostic information with regard to heroin exposure in the combination with other clues (e.g., heroin seizures at the scene).