Spectrometer Ion Source Research Articles

RRLC-TOF/MS in identification of plasma constituents and metabolites of epimedium in rats after intragastric administration

Objective To identify the constituents and metabolites of epimedium in rat plasma by rapid-resolution liquid chromatography-time of flight mass spectrometry(RRLC-TOF/MS)after intragastric administration,so as to explore the active ingredients and metabolites of epimediumin vivo.Methods The separation was performed on a SHISEIDO MG C18 reverse phase column(3.0 mm×100 mm,3μm).The mobile phase consisted of water containing 0.1% formic acid and acetonitrile was used as gradient elute.The flow rate was 0.6mL/min,post-column split ratio was 31,and the temperature of column was 25℃.Time-of-flight mass spectrometer(TOF/MS)and electrospray ion source(ESI)were applied for qualitative analysis under positive ion mode,with the mass scan range being m/z 100-1 000.Results Three prototype constituents and 4metabolites of epimedium were identified in rat plasma.Conclusion A rapid and efficient RRLC-TOF/MS method has been established for studying the constituents and metabolites of epimediumin vivo,which provides a reference for further pharmacodynamics experiments.

Rapid identification of chemical constituents in Salvia chinensis by HPLC-TOF-MS

It's established a high-performance liquid chromatography-time of flight mass spectrometry(HPLC-TOF-MS) method to analyze chemical constituents in Salvia chinensis. The separation was performed on a SHISEIDO MG C18 reverse phase column (3.0 mm x 100 mm, 3 microm). The mobile phase consisted of acetonitrile (A) and water (containing 0.1% formic acid, B) was used as gradient elute. The gradient of a phase, 10%-90% (0-33 min), 90% (33-40 min). The flow rate was 0.6 mL x min(-1). Post-column split ratio was 2:1. Temperature of column was 25 degrees C. Time-of-flight mass spectrometer (TOF-MS) and electrospray ion source (ESI) was applied for qualitative analysis under positive ion mode, and mass scan range was m/z 100-1 000. As a result,28 of the major chemical constituents of S. chinensis were identified by HPLC-TOF-MS. In this study, a rapid and efficient method for studying the chemical constituents in S. chinensis by HPLC-TOF-MS was established, which paves a way for the quality control and further studies of the herb in vivo.

RRLC-TOF/MS in rapid identification of 43 chemical constituents of epimedium

Objective To use rapid-resolution liquid chromatography-time of flight mass spectrometry(RRLC-TOF/MS) for analyzing the chemical constituents of epimedium.Methods The separation was performed on a SHISEIDO MG C18 reverse phase column(3.0 mm×100 mm,3 μm).The mobile phase consisted of water containing 0.1% formic acid;acetonitrile was used as gradient elute.The gradient of A phase was as following: 5%-19%(0-3 min),19%-32%(3-13 min),32%-52%(13-25 min),and 52%-70%(25-30 min).The flow rate was 0.6 ml/min,post-column split ratio was 31,and the temperature of column was 25℃.Time-of-flight mass spectrometer(TOF/MS) and electrospray ion source(ESI) was applied for qualitative analysis under the positive ion mode,and mass scan range was m/z 100-1 000.Results A total of 43 chemical constituents were identifled from epimedium by RRLC-TOF/MS in one run.Conclusion A rapid and efficient RRLC-TOF/MS approach for identifying the chemical constituents of epimedium has been successfully established,which paves a way for quality control and further in vivo studies of epimedium.

Initial measurements with the SUERC accelerator mass spectrometer

10Be, 14C, 36Cl and 129I test measurements have been made with a new Pelletron-based accelerator mass spectrometer operating at up to 5.2 MV. All ion detection was with a versatile gas ionization detector. Low-background radiocarbon measurements with 2% scatter of identical samples was performed with both spectrometer ion sources. 10Be/Be backgrounds of 3×10−15 were achieved using a gas cell adjoining the detector for 10B suppression. High sample-throughput Cl AMS with 36Cl/Cl backgrounds of 4×10−15 was accomplished.

Initial measurements with the SUERC accelerator mass spectrometer

10Be, 14C, 36Cl and 129I test measurements have been made with a new Pelletron-based accelerator mass spectrometer operating at up to 5.2 MV. All ion detection was with a versatile gas ionization detector. Low-background radiocarbon measurements with 2% scatter of identical samples was performed with both spectrometer ion sources. 10Be/Be backgrounds of 3 × 10−15 were achieved using a gas cell adjoining the detector for 10B suppression. High sample-throughput Cl AMS with 36Cl/Cl backgrounds of 4 × 10−15 was accomplished.

Measurement of sample charging during sputtering of III–V materials and devices

A common problem in the analysis of non conducting solids using ion bombardment (sputtering) is charging of the sample, which may affect the electrostatics of a mass spectrometer's ion source, and hence ion transmission efficiency and reproducibility. The voltage changes induced on samples of III–V materials and devices during sputtering are measured in real time via the Stark effect in a resonance ionization mass spectrometer. High-lying electronic (Rydberg) levels of Ga are spectrally shifted by the strong electric field (> 14 kV cm ) present in the instrument. The Stark-shifted lines are a beneficial diagnostic to probe the ion source's local electric field, which depends on the sample position and potential. Sample charging and edge effects modify the instrument's ion transmission and reproducibility. Changes corresponding to 10 V in the sample's bias can be detected spectrally. Continuous and pulsed sputtering produce different voltage shifts under a variety of incident primary ion types (Xe + and O 2 +), energies and doses. Charging of semi-insulating GaAs is significant enough at 2 keV to deflect the ion beam out of the analysis area in the ion source. At 6 keV, the beam is not moved as much even though the amount of charging is about the same.

Magic-angle thermal desorption mass spectroscopy

Accurate quantitative measurements of desorption rates or adsorbate coverages in thermal desorption mass spectroscopy (TDS) using line-of-sight mass spectrometers are hindered by the fact that the angular distributions of desorption flux can vary widely from desorbate to desorbate, ranging from cos 1ø to cos 9 ø for most species studied to date (ø = polar angle from surface normal). These differences can easily lead to errors exceeding 400% in measuring the relative desorption rates of different species. We show here that, by placing the mass spectrometer's ion source or entrance aperture at a “magic-angle” ø mthese errors can be reduced to less than 26% maximum deviation (or ± 7% standard deviation). Depending upon the sample-to-detector distance, ø m varies from ~ 42° to 34°. It is recommended that TDS experiments be performed at this “magic-angle” for improvement in the quantitative accuracy of coverage or rate measurements.

The mass spectra of nitrosulphanilamides. Observation of thermally generated products from 4‐(piperidylsulphonyl)‐2‐nitroacetanilide

AbstractIn addition to the expected electron impact induced fragmentation, the mass spectra of substituted nitrosulphanilamides, such as 4‐(piperidylsulphonyl)‐2‐nitroacetanilide, exhibit peaks due to imidazoles, imidazole‐N‐oxides and furazans, which are formed thermally in the spectrometer ion source.

Spectrometer for on-line analysis of radionuclides (Solar)

A mass spectrometer has been built for on-line analysis of fission product nuclides. The spectrometer ion source is located inside the thermal column of a TRIGA reactor and consists of a high-temperature oven containing fissile target material. Fission product nuclides born in the target are thermally ionized and accelerated out of the reactor through a 2.3 m long flight tube. Outside the reactor the ion beam is deflected 90° by an electrostatic mirror. Mass analysis of the ions takes place in a 30.5 cm radius, 60° deflection magnetic field. The system is intended initially to measure relative independent and cumulative yields of Rb, Cs, Br, and I isotopes with half-lives as short as 0.1 s. Other applications include nuclear spectroscopy, delayed-neutron emission measurements, and measurements of nuclidic masses and nuclear moments of the separated isotopes produced by the system.

A study of some diffusion pump oils using a six-inch radius 60° sector field mass spectrometer

A six-inch radius 60° sector field mass spectrometer was used to determine the spectra of three types of oil commonly used in ultrahigh vacuum diffusion pumps. By building up a record of these spectra it is possible to determine when the vacuum system has become contaminated with one of these oils. A brief description of the spectrometer is given followed by the techniques used to introduce the oil vapours into the spectrometer ion source at various temperatures up to 300°C. Three oils were examined: Santovac 5 (a polyphenyl ether), Apiezon C, and Silicone MS.704. The most significant aspects of the Santovac 5 spectrum are its relative simplicity and the 100 per cent molecular ion peak at 446 with a 30 per cent doubly ionised species at 223 indicating good thermal stability. The oil was baked out of the vacuum system to leave a background free spectrum and only slight contamination of the ion source occurred which was cured in situ by high voltage treatment. The Apiezon C oil gave rise to a complex spectrum typical of the breakdown of a hydrocarbon and produced severe source contamination in a relatively short time which could not be removed by baking or other methods. The silicone oil spectrum showed fairly discrete groups of peaks at intervals up to mass 499, but again source contamination was a major problem probably caused by polymerisation under the action of ion and electron bombardment. It was concluded that the most suitable oil for mass spectrometer applications was the Santovac 5.