Structure elucidation of degradation products of the antibiotic amoxicillin with ion trap MSn and accurate mass determination by ESI TOF (original) (raw)
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Morrls, H. R.; Panico, M.; Haskine, N. J. Int. J . Mass Spectrom. Ion Ens, W.; Standing, K. C.; Westmore, J. 6.; Ogllvie, K. K.; Nemer, M. J. Anal. Chem. 1982, 5 4 , 960-966. Dell. A.: Morris. H. R. Biochem. Bio~hvs. Res. Commun. 19f12, 106. Gamo, K.; Ukegawa, T.; Inomoto, Y.; Ka, K. K.; Namba, S. Jpn. J. Dlxon, A.; Colliex, C.; Sudraud, P.; van de Walle, J. Surf. Sci. 1981, L379-L362. A new typo of multldlmenslonal mass spectrometer Is; presented. Utlllratlon of Ion beam pulsing and time-resolved detectlon techniques In a magnetlc sector mass spectrometer allows slmiiltaneous momentum and velocity analysis of the Ions. Thls oomblnatlon provldes energy-lndependent Ion mass asslgnments. Parent, daughter, and neutral loss spectra can be obtalnedl as In conventional MS/MS Instruments. Equatlons for mass determination are glven and various scannlng modes are described. Metastable Ion decomposltlons are used to
Exact mass measurement by Fourier transform mass spectrometry
Analytical Chemistry, 1980
Reported here for the first time is a technique utilizing Fourier Transform Mass Spectrometry (FT/MS) for determining elemental compositions of gas-phase ions by exact mass measurement. In contrast to previous literature reports of mass measurement errors averaging 77 ppm via ICR measurements, accuracies averaging 3 ppm havl? been achieved in the present work. Moreover, in the course of this study, the phenomenon of shifts in ion cyclotron resonance frequency with the number of ions in the cell has been investigated. The resonance shiis are caused by electric fiMs associated with ion space charge. The consequences of this effect for mass measurement accuracy are discussed.
Journal of the American Society for Mass Spectrometry, 1999
We herein report upon an approach whereby the interpretation of tandem mass spectrometry spectra can be both expedited and simplified via the accurate mass assignment of product ions utilizing a tandem quadrupole time-of-flight mass spectrometer (QqTOF). The applicability of the QqTOF in the drug metabolism laboratory is illustrated by the elucidation and differentiation of the dissociative pathways for Bosentan and its hydroxylated and demethylated metabolites. Target analyte fragmentation mechanisms were readily achieved by the measurement of product ions with a mass accuracy Ͻ5 ppm, possible by single-point internal recalibration using the residual precursor ion as calibrant. Differentiation of both precursor and product ions from nominally isobaric matrix species derived from biological extracts is demonstrated by operation of the QqTOF at resolutions of ϳ8000 (m/⌬m FWHM).
Veterinary World, 2012
The mass spectrometer is an instrument that can measure the masses and relative concentrations of atoms and molecules. It is also an analytical technique that identifies the chemical composition of a compound or sample based on the mass-to-charge ratio of charged particles. A mass spectrometer has three essential modules, an ion source-which transforms the molecules in a sample into ionized fragments, a mass analyser-which sorts the ions by their masses by applying electromagnetic field and a detector-which measures the value of some indicator quantity and thus provides data for calculating the abundances each ion fragment present The technique has both qualitative and quantitative uses. Mass spectrometers are sensitive detectors of isotopes based on their masses. They are used in carbon dating and other radioactive dating processes. The combination of a mass spectrometer and a gas chromatograph makes a powerful tool for the detection of trace quantities of contaminants or toxins. A number of satellites and spacecraft have mass spectrometers for the identification of the small numbers of particles intercepted in space Mass spectrometry is an important tool for characterization of proteins. Pharmacokinetics is often studied using mass spectrometry because of the complex nature of the matrix (often blood or urine. Mass spectrometers are used for the analysis of residual gases in high vacuum systems.
Application of Mass Spectroscopy in Pharmaceutical and Biomedical Analysis
Spectroscopic Analyses - Developments and Applications, 2017
Mass spectrometry (MS) is a powerful analytical tool with many applications in pharmaceutical and biomedical field. The increase in sensitivity and resolution of the instrument has opened new dimensions in analysis of pharmaceuticals and complex metabolites of biological systems. Compared with other techniques, mass spectroscopy is only the technique for molecular weight determination, through which we can predict the molecular formula. It is based on the conversion of the sample into ionized state, with or without fragmentation which are then identified by their mass-to-charge ratios (m/e). Mass spectroscopy provides rich elemental information, which is an important asset to interpret complex mixture components. Thus, it is an important tool for structure elucidation of unknown compounds. Mass spectroscopy also helps in quantitative elemental analysis, that is, the intensity of a mass spectra signal is directly proportional to the percentage of corresponding element. It is also a noninvasive tool that permits in vivo studies in humans. Recent research has looked into the possible applications of mass spectrometers in biomedical field. It is also used as a sensitive detector for chromatographic techniques like LC-MS, GC-MS and LC/MS/MS. These recent hyphenated technological developments of the technique have significantly improved its applicability in pharmaceutical and biomedical analyses.
Rapid Communications in Mass Spectrometry, 2001
The interpretation of mass spectra is a key process during compound identification, and the combination of tandem mass spectrometry (MS/MS) with high-accuracy mass measurements may deliver crucial information on the identity of a compound. Obtaining accurate mass data of fragment ions in MS/MS reveals the particular problem of mass calibration when a lockmass, which is frequently used to obtain accurate masses in MS, is absent. An alternative technique is to recalibrate the MS/MS spectrum using a reference MS/MS spectrum acquired under the same conditions. We have tested and validated this approach using a hybrid quadrupole/orthogonal acceleration reflectron-type time-of-flight (TOF) mass spectrometer. The results were compared with those obtained under similar conditions on a Fourier transform ion cyclotron resonance (FT-ICR) instrument. We found that the mass accuracy observed with such an`external' recalibration on the TOF instrument in MS/MS is identical to what can be obtained on a similar instrument operating in one-dimensional MS mode using the lockmass technique. However, mass accuracy in both cases is one order of magnitude inferior to that obtained using FTMS, and also inferior to that observed using sector field MS when operated at comparable resolution. Nevertheless, for small (<200 Da) molecules, this mass accuracy was still sufficient to have the`true' elemental composition identified as the first hit in about 70% of all cases. It was possible to elucidate the fragmentation mechanism of eight azaheterocycles containing a pyridine moiety, where the accurate mass data from the TOF instrument allowed distinction between two alternative fragmentation pathways.
Journal of Chromatography A, 1999
The purpose of the study was to examine the intra-and interlaboratory reproducibility of mass spectra obtained with liquid chromatography-atmospheric pressure ionization mass spectrometry (LC-API-MS) both in electrospray (ESI) and atmospheric pressure chemical ionization (APCI) modes. Toxicologically relevant drugs of different polarity were selected as test substances: morphine-6-glucuronide, 6-monoacetylmorphine, codeine, lysergic acid diethylamide, methylenedioxymethamphetamine. The study was performed in two laboratories using identical instruments and in one using a slightly different instrument. Basic instrument settings and mobile phase were identical in all laboratories. Mass spectra of drugs were taken at four collision energy voltages and using mobile phase of different composition (four concentration levels of acetonitrile and of ammonium formate buffer). The experiments demonstrated that mass spectra of given drugs, obtained in identical conditions with identical instruments, may show very different degrees of fragmentation. Mass spectra obtained with different instruments differed profoundly not only in the degree of fragmentation, but also different fragments and adducts were observed. Short-term intralaboratory reproducibility of mass spectra was satisfactory. On the other hand, the long-term experiments showed different degrees of fragmentation of APCI-generated mass spectra at nominally identical fragmentation energy. The changes in the composition of the mobile phase (concentration of organic modifier or buffer molarity) did not affect the reproducibility of fragmentation to any relevant degree.The study showed that the interlaboratory exchange and use of mass spectrum library, generated by single-quadrupole LC-API-MS instruments, is hardly feasible at the moment, even under very carefully standardized conditions.
Rapid Communications in Mass Spectrometry, 2005
Atomic masses and isotopic abundances are independent and complementary properties for discriminating among ion compositions. The number of possible ion compositions is greatly reduced by accurately measuring exact masses of monoisotopic ions and the relative isotopic abundances (RIAs) of the ions greater in mass by þ1 Da and þ2 Da. When both properties are measured, a mass error limit of 6-10 mDa (<31 ppm at 320 Da) and an RIA error limit of 10% are generally adequate for determining unique ion compositions for precursor and fragment ions produced from small molecules (less than 320 Da in this study). 'Inherent interferences', i.e., mass peaks seen in the product ion mass spectrum of the monoisotopic [MþH] þ ion of an analyte that are À2, À1, þ1, or þ2 Da different in mass from monoisotopic fragment ion masses, distort measured RIAs. This problem is overcome using an ion correlation program to compare the numbers of atoms of each element in a precursor ion to the sum of those in each fragment ion and its corresponding neutral loss. Synergy occurs when accurate measurement of only one pair of þ1 Da and þ2 Da RIAs for the precursor ion or a fragment ion rejects all but one possible ion composition for that ion, thereby indirectly rejecting all but one fragment ion-neutral loss combination for other exact masses. A triplequadrupole mass spectrometer with accurate mass capability, using atmospheric pressure chemical ionization (APCI), was used to measure masses and RIAs of precursor and fragment ions. Nine chemicals were investigated as simulated unknowns. Mass accuracy and RIA accuracy were sufficient to determine unique compositions for all precursor ions and all but two of 40 fragment ions, and the two corresponding neutral losses. Interrogation of the chemical literature provided between one and three possible compounds for each of the nine analytes. This approach for identifying compounds compensates for the lack of commercial ESI and APCI mass spectral libraries, which precludes making tentative identifications based on spectral matches. Published in 2005 by John Wiley & Sons, Ltd. Each year 2800 high-volume production chemicals (those with annual production of at least 10 6 lbs) 1 and 87 000 commercially produced chemicals, 2 along with their synthetic precursors, byproducts, transformation products, and metabolites, ultimately enter waste streams. The ability to identify compounds not targeted by routine analytical methods is important for assessing risks posed to aquatic ecosystems and to human health. In addition, sabotage agents not included on target lists of analytical methods could pose identification problems. Mass spectrometry (MS) has been used extensively for structural elucidation of chemical compounds. Two independent physical properties distinguish among the MS ion compositions possible for a given nominal mass: the exact masses of ions and the relative isotopic abundances (RIAs) of ions greater in mass by 1 Da and 2 Da (in this work, these higher mass ions will refer to [MþHþ1] þ and [MþHþ2] þ ions) that arise from the presence of atoms of heavier stable isotopes of elements, e.g., 13 C, 2 H, 15 N, 17 O, 18 O, 33 S, 34 S, 37 Cl, and 81 Br. Ion composition elucidation (ICE) is a highresolution MS technique 3 that determines both exact masses and RIAs by acquiring selected ion recording (or multiple ion detection) data on a chromatographic elution time scale. Simultaneous measurement of the exact masses and RIAs of the þ1 Da and þ2 Da isotopic profiles increases by four-fold the upper mass limit of ions for which a unique elemental composition can be determined. 4 Over the last decade, ICE Published in 2005 by John Wiley & Sons, Ltd.