Determination of LSD and N-demethyl-LSD in urine by liquid chromatography coupled to electrospray ionization mass spectrometry.

A sensitive and highly specific method for the determination of LSD and N-demethyl-LSD in urine, using combined liquid chromatography and mass spectrometry (LC-MS) with electrospray ionization, has been developed. Extrelut-3 extraction cartridges were used for a basic sample clean-up. Elution was obtained by toluene-diethyl ether (60:40, v/v). A Nucleosil C18 (150 X 1 mm I.D.) reversed-phase column was used for the chromatographic separation, together with a mixture of 2 mM ammonium formate buffer (pH 3) and acetonitrile (70:30, v/v) as mobile phase. Recoveries were 93 and 80%, detection limits 0.025 and 0.035 ng/ml for LSD and N-demethyl-LSD, respectively. Intra-assay precision, studied at four concentrations, was better than 9% at the ng/ml range and better than 14% at 0.10 ng/ml for both compounds. Limits of quantitation were 0.05 and 0.10 ng/ml for LSD and N-demethyl-LSD, respectively. Reproducibility was good and linearity excellent for LSD in the range from 0.05 to 20 ng/ml (r>0.9999, n=7).

Applications of liquid chromatography--mass spectrometry in analytical toxicology: a review.

Liquid chromatography-mass spectrometry (LC-MS), after long-term development that has introduced seven major interfacing techniques, is finally suitable for application in the field of analytical toxicology. Various compound classes can be analyzed, and sensitivities for more or less polar analytes that are as good as or better than those of gas chromatography-mass spectrometry can be obtained with modern interfaces. In addition, because ionization is often softer than classical electron impact, some LC-MS interfaces are able to handle fragile species that are otherwise not amenable to MS. This review is intended to present LC-MS to less familiarized readers and to give an extensive overview of the application of the different coupling techniques to doping agents, drugs of abuse, forensic analysis, toxic compounds of various nature, and several toxicologically relevant therapeutic drugs. Experimental parameters such as the interfaces used, ionization methods, detection limits, and experimental details for exemplary applications are given.

Determination of buprenorphine and norbuprenorphine in whole blood by liquid chromatography-mass spectrometry.

A sensitive and highly specific method for the determination of buprenorphine and norbuprenorphine in postmortem and hemolyzed whole blood using combined liquid chromatography and mass spectrometry (LC-MS) with electrospray ionization was developed. After enzymatic hydrolysis and deproteinization with acetonitrile, Extrelut-3 cartridges were used for a preliminary basic sample cleanup. Elution by toluene-ether (50:50, v/v) was followed by an acid wash with 0.05M H3PO4 and a basic re-extraction into ether. A Nucleosil C18 (150 x 1-mm i.d.) reversed-phase column was used for the chromatographic separation together with a mixture of 2mM ammonium formate buffer (pH 3) and acetonitrile (55:45, v/v) as the mobile phase. Recoveries were between 56 and 60%, and detection limits were 0.05 ng/mL for both analytes. The coefficient of variation for repeatability was lower than 4%. Limits of quantitation were 0.1 ng/mL for buprenorphine and norbuprenorphine. Reproducibility was good, and linearity was excellent in the range of 0.1 to 100 ng/mL (r > 0.9999, n = 7).

Determination of haloperidol and its reduced metabolite in human plasma by liquid chromatography-mass spectrometry with electrospray ionization.

A sensitive and accurate liquid chromatographic-electrospray mass spectrometric (LC-ES-MS) method for the determination of haloperidol (H) and reduced haloperidol (RH) in human plasma is presented, using chlorohaloperidol as the internal standard. A 2-ml volume of plasma was subjected to basic (NaOH) extraction, acid (HCl) back-extraction, acid wash and basic (NaOH) re-extraction. The extraction solvent was hexane-isoamyl alcohol (99:1, v/v) for the whole procedure. A Nucleosil C18 column (150 x 1 mm) was used for high-performance liquid chromatography, together with 2 mM HCOONH4-acetonitrile (55:45, v/v; pH 3.0) as the mobile phase. For each drug, four characteristic ions were monitored. Linearity was assessed in the ranges 0.1-50 and 0.25-50 ng/ml for H and RH, respectively. Recoveries were 58 and 70% and detection limits were 0.075 and 0.100 ng/ml for H and RH, respectively. Correlation coefficients were better than 0.999 for both compounds. R.S.D.s for repeatability and reproducibility at 0.25 ng/ml were 11.1 and 8.5% for H and 9.4 and 11.2% for RH, respectively. One of the main advantages of (LC-ES-MS) over other detection systems is the increase in selectivity obtained by monitoring three ions of confirmation for each of the drugs.