Search results for "Mass Spectrometer"
showing 10 items of 75 documents
Direct mass measurements of neutron-deficient xenon isotopes with the ISOLTRAP mass spectrometer
2000
Abstract The masses of Xe isotopes with 124⩾ A ⩾114 have been measured using the ISOLTRAP spectrometer at the on-line mass separator ISOLDE/CERN. A mass resolving power of 500 000 was chosen resulting in an accuracy of δm ≈12 keV for all isotopes investigated. Conflicts with existing mass data of several standard deviations were found.
Mass measurements on neutron-deficient Sr and neutron-rich Sn isotopes with the ISOLTRAP mass spectrometer
2005
Abstract The atomic masses of 76,77,80,81,86,88 Sr and 124,129,130,131,132 Sn were measured by means of the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. 76 Sr is now the heaviest N = Z nucleus for which the mass is measured to a precision better than 35 keV. For the tin isotopes in the close vicinity of the doubly magic nucleus 132 Sn, mass uncertainties below 20 keV were achieved. An atomic mass evaluation was carried out taking other experimental mass values into account by performing a least-squares adjustment. Some discrepancies between older experimental values and the ones reported here emerged and were resolved. The results of the new adjustment and their impact will be pr…
The Use of Chromatographic Methods Coupled to Mass Spectrometry for the Study of Emerging Pollutants in the Environment.
2018
The consumption of compounds that improve the human health and wellness is increasing, and as a result, the residues of these substances reach the environment or food chain. For this reason, the scientific community is looking for new analytical methods that are more accurate and can detect the greatest number of compounds in different matrices. This manuscript compares different studies in abiotic and biotic matrices, where most of them (92%) uses Liquid Chromatography to separate the compounds. For the detection, most of the studies for both matrices uses, coupled to the chromatograph, a triple quadrupole mass spectrometer (50%) due to the precision to quantify the concentration of these …
Cluster isobars for high-precision mass spectrometry
1991
Doublet mass measurements of the isobars28Si3 and12C7 are performed by use of a Penning trap mass spectrometer and the Fourier transform ion cyclotron resonance (FT-ICR). The carbon and silicon cluster ions are produced by laser ablation. Results of these preliminary measurements are presented.
Routine application using single quadrupole liquid chromatography-mass spectrometry to pesticides analysis in citrus fruits.
2005
Abstract A rapid and sensitive liquid chromatography–electrospray ionization–mass spectrometry method has been developed for the routine analysis of buprofezin, bupirimate, hexaflumuron, tebufenpyrad, fluvalinate and pyriproxyfen in citrus fruits. Extracts were obtained by matrix solid-phase dispersion (MSPD) using C 18 as dispersant and dichloromethane-methanol (80:20, v/v) as eluent. Matrix effects were tested for all matrices by addition of standard to sample blank extracts (samples containing no detectable residues). Mean recoveries obtained at fortification levels between 0.01 and 5 mg kg −1 were 57–97% with relative standard deviations (RSDs) from 5 to 19%. The limits of quantificatio…
Comparison of four mass analyzers for determining carbosulfan and its metabolites in citrus by liquid chromatography/mass spectrometry
2006
Four liquid chromatography/mass spectrometry (LC/MS) systems, equipped with single quadrupole, triple quadrupole (QqQ), quadrupole ion trap (QIT) and quadrupole time-of-flight (QqTOF) mass analyzers, were evaluated for the analysis of carbosulfan and its main transformation products. The comparison of quantitative aspects (sensitivity, precision and accuracy) was emphasized. Results showed that the triple quadrupole instrument reaches at least 20-fold higher sensitivity (LOD from 0.04 to 0.4 microg kg(-1)) compared to the single quadrupole (4-70 microg kg(-1)), the QIT (4-25 microg kg(-1)) and the QqTOF (4-23 microg kg(-1)) instruments. Recoveries were over 70% for all the analytes, except …
Cluster calibration in mass spectrometry: laser desorption/ionization studies of atomic clusters and an application in precision mass spectrometry.
2003
For accurate mass measurements and identification of atomic and molecular species precise mass calibration is mandatory. Recent studies with laser desorption/ionization and time-of-flight analysis of cluster ion production by use of fullerene and gold targets demonstrate the generation of atomic clusters for calibration purposes. Atomic ion results from the Penning trap mass spectrometer ISOLTRAP, in which a carbon cluster ion source has recently been installed, are presented as an application in the field of precision mass spectrometry.
Laser desorption/ionization cluster studies for calibration in mass spectrometry
2003
Precise mass calibration is mandatory in many fields of mass spectrometry. We have performed laser desorption/ionization cluster studies with a MALDI-TOF mass spectrometer on gold and fullerene targets to produce atomic clusters. These investigations demonstrate that clusters are ideally suited for this purpose. Pulsed N 2 -laser and Nd:YAG-laser ablation was used to produce positively as well as negatively charged clusters. Earlier observations of dianionic metal clusters are confirmed. First results from the tandem Penning trap mass spectrometer ISOLTRAP using carbon clusters as mass references show how carbon clusters can be applied to precision mass spectrometry by providing absolute ma…
Combined use of liquid chromatography triple quadrupole mass spectrometry and liquid chromatography quadrupole time-of-flight mass spectrometry in sy…
2012
As a suitable way for routine screening of pesticides and control of other organic contaminants in water, the combination of liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS) and liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) has been applied to the analysis of 63 surface and waste water samples after conventional solid-phase extraction (SPE). The extracts were screened for 43 pesticides or degradation products by LC-QqQ-MS/MS achieving limits of detection (LOD) ranged from 0.04 to 2 ng L(-1). Of the 43 selected pesticides, 33 were detected in water samples. The ESI-QTOF MS instrument was run using two simultaneous acquisi…
(Supplementary Table 1) 230Th/U results for stalagmite Cuba Grande (CG) from Pinar del Rio
2010
We present 22 U-series ages for a stalagmite from north-western Cuba based on multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and thermal ionisation mass spectrometry (TIMS). Our results reveal that the stalagmite continuously grew within the last ~1400a. Low uranium content of the sample and thus, extremely low 230Th concentrations limit the precision and accuracy of 230Th/U-dating by TIMS. Samples measured by MC-ICPMS show a high variability of 232Th content along the growth axis with some sections significantly affected by initial 230Th from a detrital phase. An a-priori bulk earth ratio for (238U/232Th) cannot be used to accurately account for this initial 230Th.…