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      Current role of LC-MS(/MS) in doping control

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          Detection of JWH-018 metabolites in smoking mixture post-administration urine.

          Smoking mixtures containing the cannabimimetic indoles may still be available over-the-counter in several countries. Due to the high affinity of these compounds to the cannabinoid receptors, their effective dose is lower than that of the marijuana products resulting in a low concentration of the excreted metabolites accompanied by a higher psychoactive potency. Up to now the in vivo metabolism of the cannabimimetic indoles seems to be insufficiently investigated and no data have been published on an assay of JWH-018 in urine. In this publication the urinary metabolites of JWH-018 are reported. Using gas and liquid chromatography combined with tandem mass spectrometry two main monohydroxylated metabolites were identified in the forensic urine samples. Based on the differences in their electron ionization MS/MS spectra it is supposed that one is formed by hydroxylation of the indole ring whilst the other by hydroxylation of the N-alkyl chain. The main metabolites are almost completely glucuroconjugated, whereas minor ones (N-despentyl hydroxy-, carboxy-, dihydroxy-, and reduced di- and trihydroxy metabolites) were also present in the free fraction. The parent compound was not detected in urine. (c) 2010 Elsevier Ireland Ltd. All rights reserved.
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            Favorable effects of weak acids on negative-ion electrospray ionization mass spectrometry.

            Despite widespread use in pharmacokinetic, drug metabolism, and pesticide residue studies, little is known about the factors governing response during reversed-phase liquid chromatography coupled with negative-ion electrospray ionization (ESI(-)) mass spectrometry. We examined the effects of various mobile-phase modifiers on the ESI(-) response of four selective androgen receptor modulators using a postcolumn infusion system. Acetic, propionic, and butyric acid improved the ESI(-) responses of analytes to varying extents at low concentrations. Formic acid suppressed ionization, as did neutral salts (ammonium formate, ammonium acetate) and bases (ammonium hydroxide, triethylamine) under most conditions. Two modifiers (2,2,2-trifluoroethanol, formaldehyde) that produce anions with high gas-phase proton affinity increased ESI(-) responses. However, the concentrations of these modifiers required to enhance ESI(-) response were higher than that of acidic modifiers, which is a phenomenon likely related to their low pK(a) values. 2,2,2-Trifluoroethanol increased response of more hydrophobic compounds but decreased response of a more hydrophilic compound. Formaldehyde improved response of all the compounds, especially the hydrophilic compound with lower surface activity. In summary, these results suggest that an ideal ESI(-) modifier should provide cations that can be easily electrochemically reduced and produce anions with small molecular volume and high gas-phase proton affinity.
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              Growth hormone, IGF-I and insulin and their abuse in sport.

              There is widespread anecdotal evidence that growth hormone (GH) is used by athletes for its anabolic and lipolytic properties. Although there is little evidence that GH improves performance in young healthy adults, randomized controlled studies carried out so far are inadequately designed to demonstrate this, not least because GH is often abused in combination with anabolic steroids and insulin. Some of the anabolic actions of GH are mediated through the generation of insulin-like growth factor-I (IGF-I), and it is believed that this is also being abused. Athletes are exposing themselves to potential harm by self-administering large doses of GH, IGF-I and insulin. The effects of excess GH are exemplified by acromegaly. IGF-I may mediate and cause some of these changes, but in addition, IGF-I may lead to profound hypoglycaemia, as indeed can insulin. Although GH is on the World Anti-doping Agency list of banned substances, the detection of abuse with GH is challenging. Two approaches have been developed to detect GH abuse. The first is based on an assessment of the effect of exogenous recombinant human GH on pituitary GH isoforms and the second is based on the measurement of markers of GH action. As a result, GH abuse can be detected with reasonable sensitivity and specificity. Testing for IGF-I and insulin is in its infancy, but the measurement of markers of GH action may also detect IGF-I usage, while urine mass spectroscopy has begun to identify the use of insulin analogues.
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                Author and article information

                Journal
                Analytical and Bioanalytical Chemistry
                Anal Bioanal Chem
                Springer Science and Business Media LLC
                1618-2642
                1618-2650
                August 2011
                March 20 2011
                August 2011
                : 401
                : 2
                : 405-420
                Article
                10.1007/s00216-011-4859-9
                7ddce099-b206-43c7-b4e7-7ab8b687bb91
                © 2011

                http://www.springer.com/tdm

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