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Electron ionization mass spectrum of the steroid alcohol brassicasterol. Mass spectral interpretation is the method employed to identify the chemical formula, characteristic fragment patterns and possible fragment ions from the mass spectra.
The photoionization detector was applied to gas chromatography (GC) three years later, in 1976. [5] A PID is highly selective when coupled with a chromatographic technique or a pre-treatment tube such as a benzene-specific tube. Broader cuts of selectivity for easily ionized compounds can be obtained by using a lower energy UV lamp.
A gas detector can sound an alarm to operators in the area where the leak is occurring, giving them the opportunity to leave. This type of device is important because there are many gases that can be harmful to organic life, such as humans or animals. Gas detectors can be used to detect combustible, flammable and toxic gases, and oxygen depletion.
The detection limit for electron capture detectors is 5 femtograms per second (fg/s) and the detector commonly exhibits a 10,000-fold linear range. [ citation needed ] This made it possible to detect halogenated compounds such as pesticides and CFCs , even at levels of only one part per trillion ( ppt ), thus revolutionizing our understanding ...
As benzene is ubiquitous in gasoline and hydrocarbon fuels that are in use everywhere, human exposure to benzene is a global health problem. Benzene targets the liver, kidney, lung, heart and brain and can cause DNA strand breaks and chromosomal damage, hence is teratogenic and mutagenic. Benzene causes cancer in animals including humans.
A journal entry is the act of keeping or making records of any transactions either economic or non-economic. Transactions are listed in an accounting journal that shows a company's debit and credit balances. The journal entry can consist of several recordings, each of which is either a debit or a credit. The total of the debits must equal the ...
Proportional counters or various types of solid-state detectors (PIN diode, Si(Li), Ge(Li), silicon drift detector SDD) are used. They all share the same detection principle: An incoming X-ray photon ionizes a large number of detector atoms with the amount of charge produced being proportional to the energy of the incoming photon. The charge is ...
Established semiconductor detector technology based on silicon and germanium have excellent energy resolution at X-ray energies under 30 keV but above this, due to a reduction in the material mass attenuation coefficient, the detection efficiency is dramatically reduced. To detect high energy X-rays, detectors produced from higher density ...