Mass detector

Eig. 17. Cross-sectional schematic of a microbolometer photodetector. Micromachining is used to constmct small, very low mass detectors. The dimension... 

GC/MS Hewlett Packard HP5890 connected to HP5971 mass detector with a jet separator... 

ESI-MS has emerged as a powerful technique for the characterization of biomolecules, and is the most versatile ionization technique in existence today. This highly sensitive and soft ionization technique allows mass spectrometric analysis of thermolabile, non-volatile, and polar compounds and produces intact ions from large and complex species in solution. In addition, it has the ability to introduce liquid samples to a mass detector with minimum manipulation. Volatile acids (such as formic acid and acetic acid) are often added to the mobile phase as well to protonate anthocyanins. A chromatogram with only the base peak for every mass spectrum provides more readily interpretable data because of fewer interference peaks. Cleaner mass spectra are achieved if anthocyanins are isolated from other phenolics by the use of C18 solid phase purification. - ... 

Mjj and My or [q] for the broad MWD standard are taken as known quantities. Fy(v) is the normalized chromatogram for the broad MWD standard obtained with a mass detector. D2 is the slope of the molecular weight calibration curve at the peak position of the chromatogram (the equation of the tangent is given by M(v) = Dj exp(-D2v). is the variance of the single-species chromatogram... 

The apparatus employed for this study was a Waters Associates Model ALC/GPC 300 with a differential refractometer as mass detector operated at room temperature. A 2 ml sample loop with polymer concentrations of 0.01-0.1 wt.% cUid a 5 ml siphon were employed with mobile phase flowrates in the reuige 1-8 ml/min. 

Charlesworth, J. M., Evaporative analyzer as a mass detector for liquid chromatography, Anal. Chem., 50, 1414, 1978. 

Waters Corp., Thermabeam Mass Detector (Integrity System Publications), Waters Corp., Milford, MA... 

Although often used as a qualitative (identification) tool, MS may act as a quantitative inorganic mass detector. Quantification of organic analytes often takes place in combination with chromatography or in tandem MS mode. It should be realised that mass spectrometry is certainly not a panacea for all polymer/additive problems, although it is developing into a major tool for this purpose. 

The mass spectrometer is mainly used as a mass detector in chromatography (GC, SFC, HPLC, SEC, TLC). With the great variety of interfaces, ionisation modes and mass spectrometers, chromatography-mass spectrometry is highly diversified. High-resolution separations combined with accurate mass measurements and element-sensitive detection (MIP, ICP) have been reported. 

Automated multiple development (chamber) (2) Atmospheric mass detector (3) Advanced method development... 

The concept of peak capacity is rather universal in instrumental analytical chemistry. For example, one can resolve components in time as in column chromatography or space, similar to the planar separation systems however, the concept transcends chromatography. Mass spectrometry, for example, a powerful detection method, which is often the detector of choice for complex samples after separation by chromatography, is a separation system itself. Mass spectrometry can separate samples in time when the mass filter is scanned, for example, when the mass-to-charge ratio is scanned in a quadrupole detector. The sample can also be separated in time with a time-of-flight (TOF) mass detector so that the arrival time is related to the mass-to-charge ratio. 

Simple homopolymers, where monodisperse standards and suitable solvents are available, are easily characterized by SEC. Homopolymers for which no monodisperse standards are available additionally require some more elaborate detection system for transformation of the retention time into molecular weight. This can be done by, e.g., universal calibration. Alternatively, an absolute molar mass detector, like an on-line light scattering detector or mass spectrometer, can be used. 

Usually 4He is blown through a capillary towards the zone of the system under test where a leak is suspected. The system or vacuum component is pumped by the LDs and helium penetrates. LD and the mass detector reveal the presence of He. The art of leak detection is described in ref. [19,20]. 

Burst signals (supemovae) have been the primary target for the resonant mass detectors. The minimum detectable perturbation of the metric sensor caused by a burst of GW of duration r is ... 

MS condition — An API 4000 equipped with a Turbo Ionspray from Applied Biosystems was used as the mass detector and [M + NH4]+ was chosen as the precursor ion for multiple reaction monitoring (MRM) due to the lack of protonated molecular ions. A transition of m/z 434.4 — 273.2 was chosen for paricalcitol and m/z 450.5 —> 379.2 was selected for the structure analog internal standard. 

MS condition — An API 3000 equipped with a Turbo Ionspray from Applied Biosystems was used as the mass detector. [M - II was chosen as the precursor ion for multiple reaction monitoring... 

Model RR/066 351 and 352 pumps models 750/16 variable-wavelength UV monitor detector 750/11 variable filter UV detector, MPD 880S multiwave plasma detector, 750/14 mass detector 750/350/06 electrochemical detector refractive index detector HPLC columns column heaters, autosamplers, pre-columns derivatization systems, solvent degassers, preparative HPLC systems... 

Quadmpole ion traps are very useful instruments that can be interfaced between various ionization sources and the mass detector. These instruments store ions of a selected mass-to-charge (m/z) ratio within their... 

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