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Lacroix C.,Pharmacokinetic and Toxicology Laboratory | Saussereau E.,Pharmacokinetic and Toxicology Laboratory
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2012

Due to the non-polar nature and the absence of an ionizable group on the cannabinoids, the ionization efficiency in electrospray is low and leads to poor limits of detection (LOD). The reaction of chloride dabsyl with the phenolic OH group of cannabinoids results in a product containing a tertiary amine, which is easily protonated in positive electrospray mode and can significantly improve the cannabinoids LOD. A rapid, selective and sensitive LC/MS-MS method was developed for quantitative determination of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH), cannabinol (CBN) and cannabidiol (CBD), in micro volume blood samples following dabsyl derivatization to enhance signal intensity. The method comprised protein precipitation followed by derivatization with dabsyl chloride and subsequent analysis using liquid chromatography-tandem mass spectrometry (LC/MS-MS). Chromatographic separation was achieved using a 150mm×2.1mm C18 analytical column maintained at 65°C and eluted with a gradient of water and acetonitrile, both containing 0.2% formic acid. The run time was 8min. The assay was successfully validated using the approach based on the accuracy profile. Lower limits of quantification (LOQ) were 0.25ng/mL for THC and THC-COOH, 0.30ng/mL for 11-OH-THC, 0.40ng/mL for CBN and 0.80ng/mL for CBD. A comparative study of cannabinoids in blood and plasma, as determined by the developed LC/MS-MS method or the in-house GC/MS-MS technique, demonstrated an excellent correlation between the two methods. Dabsylation was also tested on-line with a spiral of peek tubing placed in the LC/MS-MS column heater at 65°C before the analytical column. The results obtained with on-line dabsyl derivatization were similar to those observed off-line. © 2012 Elsevier B.V. Source


Saussereau E.,Pharmacokinetic and Toxicology Laboratory | Lacroix C.,Pharmacokinetic and Toxicology Laboratory | Gaulier J.M.,Limoges University Hospital Center | Goulle J.P.,Pharmacokinetic and Toxicology Laboratory
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2012

A novel approach has been developed for the illicit drugs quantitative determination using dried blood spots (DBS) on filter paper. The illicit drugs tested were opiates (morphine and its 3- and 6-glucuronide metabolites, codeine, 6-monoacetylmorphine), cocainics (ecgonine methylester, benzoylecgonine, cocaine, cocaethylene) and amphetamines (amphetamine, methamphetamine, MDA, MDMA, MDEA). The described method, requiring a small blood volume, is based on high performance liquid chromatography coupled to tandem mass spectrometry using on-line extraction. A Whatman card 903 was spotted with 30 μL of whole blood and left overnight to dry at room temperature. A 3-mm diameter disk was removed using a manual punch, suspended in 150 μL of water for 10. min with ultrasonication, and then 100 μL was injected in the on-line LC-MS/MS system. An Oasis HLB was used as an extraction column and a C18 Atlantis as an analytical column. The chromatographic cycle was performed with 20. mM ammonium formate buffer (pH 2.8) (solvent A) and acetonitrile/solvent A (90:10, v/v) gradient in 16. min. Detection was performed in positive electrospray ionization mode (ESI+) with a Quattro Micro (Waters). Recoveries of all analytes were up to 80%. DBS were stored in duplicate at 4 °C and -20 °C for up to 6 months. Illicit drugs seemed to be much more stabled at -20 °C. Furthermore, it was tested whether analysis of DBS may be as reliable as that of whole blood investigating authentic samples; significant correlations were obtained. This DBS assay has potential as rapid, sensitive and inexpensive option for the illicit drugs determination in small blood volumes, which seems of great interest in suspected cases of driving under the influence of drugs. © 2011 Elsevier B.V. Source


Lacroix C.,Pharmacokinetic and Toxicology Laboratory | Saussereau E.,Pharmacokinetic and Toxicology Laboratory | Boulanger F.,Pharmacokinetic and Toxicology Laboratory | Goulle J.P.,Pharmacokinetic and Toxicology Laboratory
Journal of Analytical Toxicology | Year: 2011

An original liquid chromatography-tandem mass spectrometry (LC-MS-MS) method coupled to online extraction has been developed for cyanide determination in blood. A method involving fluorimetric detection after naphthalene-2,3-dicarboxyaldehyde (NDA) complexation by taurine in the presence of cyanide was previously described. Its performance was limited because of the absence of an internal standard (IS). Using cyanide isotope 13C15N as IS allowed quantification in MS-MS. After the addition of 13C 15N, 25 μL of blood were diluted in water and deproteinized with methanol. Following derivatization with NDA and taurine for 10 min at 4°C, 100 μL was injected into the online LC-MS-MS system. An Oasis HLB was used as an extraction column, and a C18 Atlantis was the analytical column. The chromatographic cycle was performed with an ammonium formate (20 mM, pH 2.8) (solvent A) and acetonitrile/solvent A (90:10, v/v) gradient in 6 min. Detection was performed in negative electrospray ionization mode (ESI-) with a Quattro Micro. For quantification, transitions of derivatives formed with CN and 13C 15N were monitored, respectively, as follows: 299.3/191.3 and 301.3/193.3. The procedure was fully validated, linear from 26 to 2600 ng/mL with limit of detection of 10 ng/mL. This method, using a small blood sample, is not only simple, but also time saving. The specificity and sensitivity of LC-MS-MS coupled to online extraction and using 13C 15N as the IS make this method very suitable for cyanide determination in blood and could be useful in forensic toxicology. © 2010 Publishing Technology. Source

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