Flame ionization spectroscopy

Of particular concern in this analysis is sodium because it destroys soil structure, is associated with increased soil pH, and can be toxic to plants. Sodium can easily be determined by atomic absorption spectroscopy (AAS), flame ionization spectroscopy (FIS), and inductively coupled plasma (ICP) methods. Soil structure is discussed in Chapter 2 and the various spectroscopic methods discussed in Chapter 14. 

Historically, measurements have classified ambient hydrocarbons in two classes methane (CH4) and all other nonmethane volatile organic compounds (NMVOCs). Analyzing hydrocarbons in the atmosphere involves a three-step process collection, separation, and quantification. Collection involves obtaining an aliquot of air, e.g., with an evacuated canister. The principal separation process is gas chromatography (GC), and the principal quantification technique is wdth a calibrated flame ionization detector (FID). Mass spectroscopy (MS) is used along with GC to identify individual hydrocarbon compounds. 

Acrylonitrile in both biological and environmental samples is most commonly determined by gas chromatography with a nitrogen-phosphorus detector (GC/NPD) (Page 1985), gas chromatography/flame ionization detection (GC/FID) (EPA 1982a), or gas chromatography/mass spectroscopy (GC/MS) (Anderson and Harland 1980). Infrared spectroscopy (Jacobs and Syrjala... 

Other methods for the determination of aromatics in naphtha include a method (ASTM D5580) using a flame ionization detector and methods that use combinations of gas chromatography and Fourier transform infrared spectroscopy (GC-FTIR) (ASTM D5986) and gas chromatography and mass spectrometry (GC-MS) (ASTM D5769). 

Pleil JD, Oliver KD, McClenny WA. 1988. Ambient air analyses using nonspecific flame ionization and electron capture detection compared to specific detection by mass spectroscopy. JAPCA 38 1006-1010. 

Dialkyl peroxides (continued) colorimetry, 707-8 flame ionization detection, 708 NMR spectroscopy, 708 titration methods, 707 UV-visible spectrophotometry, 707-8 enthalpies of reactions, 153-4 graft polymerization initiation, 706 hydroperoxide determination, 685 peroxide transfer synthesis, 824-5 stmctural characterization, 708-16 electrochemical analysis, 715-16 electron diffraction, 713 mass spectrometry, 714 NMR spectroscopy, 709-11 thermal analysis, 714-15 vibrational spectra, 713-14 X-ray crystallography, 711-13 synthesis... 

In atomic absorption spectroscopy (AAS) both ionization and chemical interferences may occur. These interferences are caused by other ions in the sample and result in a reduction of the number of neutral atoms in the flame. Ionization interference is avoided by adding a relatively high amount of an easily ionized element to the samples and calibration solutions. For the determination of sodium and potassium, cesium is added. To eliminate chemical interferences from, for example, aluminum and phosphate, lanthanum can be added to the samples and calibration solutions. 

Note NA = not applicable FID = flame ionization detector DOAS = differential optical absorption spectroscopy. 

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... 

For some detectors (e.g. flame ionization, FID and mass spectroscopy, MS) the detected signal is proportional to the mass flow of the solute entering the detector, a quantity which equals the product of the concentration and the volumetric flow rate. Therefore, the detector sensitivity is still directly related to the solute concentration. 

DnR silicates in solution (4). Absolute amounts of silica present in the form of the various silicates are mentioned, together with (in brackets) their relative amounts, i.e. as if no polymeric silicates were present. These polymeric silicates, i.e., silicates consisting of more than 10 Si atoms, cannot be characterized by the chemical trapping method since the silyl esters are not volatile enough to be detected by GLC/flame ionization detection (FID) (14). Moreover, Si-NMR spectroscopy studies have never been successful in positively identifying higher molecular weight silicates than Si] ones (9). 

The formation of thiopyrylium (2) as a rearrangement ion has been invoked in the electron impact mass spectra of 2- and 3-alkylthiophenes (59CCC1602 88IZV905). The tendency toward the formation of 2, which represents the most abundant species, grows as the side-chain increases in length. Cation 2 has been also detected in the reaction zone of a C Hg/ CS2/H2 flame, by flame ionization/mass spectroscopy (84AJC511). 

GC-EID Gas chromatograph, flame ionization detector GC-MS Gas chromatograph, mass spectroscopy... 

UV and fluorescent spectroscopy can be employed down to 190 nm because there is no solvent interference. Mass spectrometry is easy because the water provides good ionization. Flame ionization detection (FID) is of particular interest because potentially it offers a sensitive and universal detector. A number of different interfaces have been used, including heated capillaries, which have been examined by Miller and Hawthorne [62], Ingelse et al. [63], and others [64, 65], who separated a range of analytes including alcohols, amino acids, and phenols. An alternative method employing a cold nebuliza-tion of the eluent has been introduced by Bone et al. [66]. They were able to detect both aliphatic and aromatic alcohols, polymers, carbohydrates, parabens, and steroids. 

The identification of the chemical forms of an element has become an important and challenging research area in environmental and biomedical studies. Two complementary techniques are necessary for trace element speciation. One provides an efficient and reliable separation procedure, and the other provides adequate detection and quantitation [4]. In its various analytical manifestations, chromatography is a powerful tool for the separation of a vast variety of chemical species. Some popular chromatographic detectors, such flame ionization (FID) and thermal conductivity (TCD) detectors are bulk-property detectors, responding to changes produced by eluates in a characteristic mobile-phase physical property [5]. These detectors are effectively universal, but they provide little specific information about the nature of the separated chemical species. Atomic spectroscopy offers the possibility of selectively detecting a wide rang of metals and nonmetals. The use of detectors responsive only to selected elements in a multicomponent mixture drastically reduces the constraints placed on the separation step, as only those components in the mixture which contain the element of interest will be detected... 

ECD = electron capture detection FID = flame ionization detector GC = gas chromatography MS = mass spectroscopy NSD = nitrogen specific detector TID = thermionic ionization detector... 

GC can achieve the highest resolution of the essential oils, but there are some significant limitations with regards to preparative scale separations. Typically, as the sample capacity is increased, the resolution of the chromatographic separation is reduced. On a lab scale, equipment is available that permits 24-hour automated and unattended separations, however, the recovery yield and sample resolution are still problematic [57]. Capillary column GC has become so routine for essential oil analysis that one rarely finds a lab without that capability. A multitude of detectors exist for GC thermal conductivity (TCD), flame ionization (FID), flame photometric (FPD), thermionic specific (TSD), photoionization (PID), electron capture (ECD), atomic emission (AED), mass spectrometry (MS), and infrared spectroscopy (FTIR) [58,59]. The TCD is used primarily with preparative-GC (packed column) because it is... 

Note Key CL = chemiluminescent EC = electro-chemical FID = flame ionization detector GC = gas chromatograph HC = hydrocarbons IR = nondispersive infrared LA = line absorption Para. = paramagnetic RS = Raman spectroscopy. 

---