Chemical ionization mass spectrometry detector

Qin BH, Yu BB, Zhang Y, Lin XC. Residual analysis of organochlorine pesticides in soil by gas chromatograph-electron capture detector (gc-ecd) and gas chromatograph-negative chemical ionization mass spectrometry (GC-NCI-MS). Environ. Forensics 2009 10 331-335. 

Chemical Ionization Mass Spectrometry (CIMS) Detector... 

ECD = electron capture detector FID = flame ionization detector GC = gas chromatography HRGC = high resolution gas chromatography LC-APCI-MS = liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry LSE = liquid-solid extraction MS = mass spectrometry PVC = polyvinyl chloride SFE = supercritical fluid extraction... 

Atomic Emission Detector Atmospheric Pressure Chemical Ionization Mass Spectrometry Chemical Abstracts Service Chemical Abstract... 

Capillary Electrophoresis Chemical Warfare Agents Chemical Weapons Convention Deuterated L-Alanine Triglycine Sulfate Dimethyl Ethylphosphonate Dimethyl Isopropylphosphonate Dimethyl Methylphosphonate Dimethyl Propylphosphonate Dimercaptotoluene Diffuse Reflectance Infrared Fourier Transform Functional Group Chromatograms Flame-Ionization Detector Fourier Transform Infrared Spectroscopy Gas Chromatography Gas Chromatography/Chemical Ionization/Mass Spectrometry Gas Chromatography/Chemical Ionization/Tandem Mass Spectrometry... 

Maoka, T., Fujiwara, Y., Hashimoto, K., and Akimoto, N. 2002. Rapid identification of carotenoids in a combination in a combination of liquid chromatography/UV-visible absorption spectrometry by phtodiode array detector and atmospheric pressure chemical ionization mass spectrometry (LC/PAD/APCI-MS). J. Oleo Sci., 5,1-9. 

Shaw LM, Edling-Owens J, Mattes R (1991) Ultrasensitive measurement of delta-9-tetra-hydrocannabinol with a high energy dynode detector and electron-capture negative chemical-ionization mass spectrometry. Clin Chem 37 2062-2068... 

Detection methods HPLC-DAD, HPLC with diode-array detection. HPLC-(ESI-MS), HPLC with electrospray ionization mass spectrometry. RP-HPLC, revcrsed-phase HPLC. UPLC/Q-TOFMS, UPLC with quadrupole-time of flight mass spectrometry. HPLC-APCI-MS, HPLC with atmospheric pressure chemical ionization mass spectrometry. CE-IT-MS, capillary elecliophoresis-ion-1r mass spectrometry. LC-ESI-ITMS, liquid chromatography-electrospray ionization ion trap mass spectrometry. LC-ELSD, LC with evaporative light scattering detector. DNBZ-Cl, 3,5-dinitrobenzoyl chloride. 

The typical atmospheric concentrations of OH and HO2 radicals in the daytime are 10 and 10 molecules cm ( 0.1 pptv and a few pptv), respectively. The detection techniques whose accuracy is thought to be satisfactory for their measurements are laser-induced fluorescence (LIF) at low pressure which is called Fluorescence Assay by Gas Expansion (FACE), and chemical ionization mass spectrometry (CIMS), and they have recently been used widely. In either of the methods, directly measured is OH, and HO2 is measured by converting to OH utilizing the reaction of HO2 -I- NO —> OH -I- NO2 (reaction (7.10)) adding NO to the atmospheric samples just before the introduction to the detector. Other than these methods, differential optical absorption spectroscopy (DOAS) is also used for the measurements of OH in fields and smog chambers. 

SP-2401" and 3% SP-2250. ° Detectors used by EPA standards procedures, include photoionization (PID)," electron capture (ECD)," Eourier transform infrared spectrometry (PTIR), " and mass spectrometry detectors (MSD)." ° Method 8061 employs an ECD, so identification of the phthalate esters should be supported by al least one additional qualitative technique. This method also describes the use of an additional column (14% cyanopropyl phenyl polysiloxane) and dual ECD analysis, which fulfills the above mentioned requirement. Among MSDs, most of the procedures employ electron impact (El) ionization, but chemical ionization (CI) ° is also employed. In all MSD methods, except 1625, quantitative analysis is performed using internal standard techniques with a single characteristic m/z- Method 1625 is an isotope dilution procedure. The use of a FTIR detector (method 8410) allows the identification of specific isomers that are not differentiated using GC-MSD. 

ECD = electron capture detector GC = gas chromatography HPLC = high-performance liquid chromatography MC = microcoulometric detector MS = mass spectrometry NICI = negative ion chemical ionization RSD = relative standard deviation SPE = solid phase extraction... 

Photoionization ti me-of-fli ght mass spectrometry is almost exclusively the method used in chemical reaction studies. The mass spectrometers, detectors and electronics are almost identical. A major distinction is the choice of ionizing frequency and intensity. For many stable molecules multi photon ionization allowed for almost unit detection efficiency with controllable fragmentation(20). For cluster systems this has been more difficult because high laser intensities generally cause extensive dissociation of neutrals and ions(21). This has forced the use of single photon ionization. This works very well for low i oni zati on potential metals ( < 7.87 eV) if the intensity is kept fairly low. In fact for most systems the ionizing laser must be attenuated. A few very small... 

For the last several years, mass spectrometry with atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) have determined the trends in the analysis of dyes. Since 1987, various variants of ESI have been used in which droplet formation was assisted by compressed air,[1,2] temperature (e.g. Turbo Ion Spray ) or ultrasound, and they were able to handle flow rates up to 1 2 ml min This made a combination of analytical RPLC and ESI easily and widely used. The reason why it often was (and is) used instead of a traditional UV-Vis detector is the better sensitivity and selectivity of MS in comparison with spectrophotometric detection. Apart from these advantages, MS offers easily interpretable structural information. However, various... 

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