‘Wrong-way-round ionization’ and screening for doping substances in human urine by high-performance liquid chromatography/orbitrap mass spectrometry
ABSTRACT To free analytical resources for new classes of doping substances, such as banned proteins, maximization of the number of compounds that can be determined with high sensitivity in a single run is highly urgent. This study demonstrates an application of 'wrong-way-round ionization' for the simultaneous detection of multiple classes of doping substances without the need to switch the polarity. A screening method for the detection of 137 compounds from various classes of prohibited substances (stimulants, diuretics, β(2)-agonists, β-blockers, antiestrogens, glucocorticosteroids and anabolic agents) has been developed. The method involves an enzymatic hydrolysis, liquid-liquid extraction and detection by liquid chromatography/orbitrap mass spectrometry with wrong-way-round ionization. Up to 64% of compounds had a 10-fold lower limit of detection (LOD) than the minimum required performance limit. To compare the efficiency of conventional ionization relative to wrong-way-round ionization of doping substances in + ESI, a fortified blank urine sample at the minimum required performance limit was analyzed using two ESI approaches. All compounds were detected with markedly better S/N in a high-pH mobile phase, with the exception of acetazolamide (minimal change in S/N, < 20%).The method was validated by spiking 10 different blank urine samples at five different concentrations. Validation parameters included the LOD, selectivity, ion suppression, extraction recovery and repeatability.
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ABSTRACT: Quantitative determination of anti-epileptic drug concentrations is of great importance in forensic toxicology cases. Although the drugs are not usually abused, they are important post-mortem cases where the question of both lack of compliance and accidental or deliberate poisoning might be raised. In addition these drugs can be relevant for driving under the influence cases. A reversed phase ultra-performance liquid chromatography-tandem mass spectrometry method has been developed for the quantitative analysis of the anti-epileptic compounds carbamazepine, carbamazepine-10,11-epoxide, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, 10-OH-carbazepine, phenobarbital, phenytoin, pregabalin, and topiramate in whole blood, using 0.1 mL sample volume with methaqualone as internal standard. Sample preparation was a simple protein precipitation with acetonitrile and methanol. The diluted supernatant was directly injected into the chromatographic system. Separation was performed on an Acquity UPLC® BEH Phenyl column with gradient elution and a mildly alkaline mobile phase. The mass spectrometric detection was performed in positive ion mode, except for phenobarbital, and multiple reaction monitoring was used for drug quantification. The limits of quantification for the different anti-epileptic drugs varied from 0.064 to 1.26 mg/L in blood, within-day and day-to-day relative standard deviations from 2.2 to 14.7% except for phenobarbital. Between-day variation for phenobarbital was 20.4% at the concentration level of 3.5 mg/L. The biases for all compounds were within ±17.5%. The recoveries ranged between 85 and 120%. The corrected matrix effects were 88–106% and 84–110% in ante-mortem and post-mortem whole blood samples, respectively. Copyright © 2014 John Wiley & Sons, Ltd.Drug Testing and Analysis 10/2014; DOI:10.1002/dta.1733 · 2.82 Impact Factor
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ABSTRACT: UltraPerformance convergence chromatography (UPC 2 Ô) is a new category of separation science which utilizes the unrealized potential of the supercritical chromatography phenomenon. UPC 2 Ô is a stand-alone, viable technique that is cost effective, sustainable, and uses green technology that lowers the use of organic solvents. Based on this advantage, we explored a simple and robust supercritical liquid-based UPC 2 method in order to increase sample throughput and productivity to quantify the diastereomers of fulvestrant. The two isomers of fulvestrant were well separated on a chiral column (150 mm Â 4.6 mm, I.D.) by applying a mixture of methanol and acetonitrile (9.5 : 0.5) as the co-solvent of the mobile phase of carbon dioxide (75%). The detection was carried out at 280 nm. We were able to achieve a three-fold reduction in retention with an isocratic mode as compared to the United States Pharmacopoeias (USP) normal phase method. This new method was validated in accordance with the ICH guidelines; it exhibited good intra-and inter-day accuracy, precision, and the results were linear over a range of 25% to 150% of the target concentration. The method could be successfully applied for the determination of the diastereomeric ratio of fulvestrant as an API and in fulvestrant injectable finished products.Analytical methods 07/2013; DOI: 10.1039/c3ay40802g(DOI: 10.1039/c3ay40802g):DOI: 10.1039/c3ay40802g. DOI:10.1039/c3ay40802g · 1.94 Impact Factor
Article: Review: Mass spectrometry in Russia.[Show abstract] [Hide abstract]
ABSTRACT: The present review covers the main research in the area of mass spectrometry from the 1990s which was about the same time as the Russian Federation emerged from the collapse of the Soviet Union (USSR). It consists of two main parts-application of mass spectrometry to chemistry and related fields and creation and development of mass spectrometric technique. Both traditional and comparatively new mass spectrometric methods were used to solve various problems in organic chemistry (reactivity of gas-phase ions, structure elucidation and problems of identification, quantitative and trace analysis, differentiation of stereoisomers, derivatization approaches etc.), biochemistry (proteomics and peptidomics, lipidomics), medical chemistry (mainly the search of biomarkers, pharmacology, doping control), environmental, petrochemistry, polymer chemistry, inorganic and physical chemistry, determination of natural isotope ratio etc. Although a lot of talented mass spectrometrists left Russia and moved abroad after the collapse of the Soviet Union, the vitality of the mass spectral community proved to be rather high, which allowed the continuation of new developments in the field of mass spectrometric instrumentation. They are devoted to improvements in traditional magnetic sector mass spectrometers and the development of new ion source types, to analysis and modification of quadrupole, time-of-flight (ToF) and ion cyclotron resonance (ICR) analyzers. The most important achievements are due to the creation of multi-reflecting ToF mass analyzers. Special attention was paid to the construction of compact mass spectrometers, particularly for space exploration, of combined instruments, such as ion mobility spectrometer/mass spectrometer and accelerating mass spectrometers. The comparatively young Russian Mass Spectrometry Society is working hard to consolidate the mass spectrometrists from Russia and foreign countries, to train young professionals on new appliances and regularly holds conferences on mass spectrometry. For ten years, a special journal Mass-spektrometria has published papers on all disciplines of mass spectrometry.European Journal of Mass Spectrometry 01/2013; 19(6):399-452. DOI:10.1255/ejms.1248 · 1.17 Impact Factor