Flame optics

Special Interests Radioactivity, application of quantum mechanics to chemistry theory of reaction rates theory of liquids, rheology molecular biology, theory of flames, optical rotation... 

If the detector is of the FID type, flame optical emission or absorption can also be used. Commercial detectors are available that use essentially nondispersive or filter analyzers coupled to a FID. Phosphorus, sulfur, and nitrogen are commonly detected by this method. A hollow-cathode light source makes possible the detection of many organometallic compounds by atomic absorption. 

The burner is mounted on an adjustable stage that allows the entire burner assembly to move horizontally and vertically. Horizontal adjustment is necessary to ensure that the flame is aligned with the instrument s optical path. Vertical adjustments are needed to adjust the height within the flame from which absorbance is... 

Miscellaneous Atomization Methods A few elements may be atomized by a chemical reaction that produces a volatile product. Elements such as As, Se, Sb, Bi, Ge, Sn, Te, and Pb form volatile hydrides when reacted with NaBH4 in acid. An inert gas carries the volatile hydrides to either a flame or to a heated quartz observation tube situated in the optical path. Mercury is determined by the cold-vapor method in which it is reduced to elemental mercury with SnCb- The volatile Hg is carried by an inert gas to an unheated observation tube situated in the instrument s optical path. 

Other Detectors Two additional detectors are similar in design to a flame ionization detector. In the flame photometric detector optical emission from phosphorus and sulfur provides a detector selective for compounds containing these elements. The thermionic detector responds to compounds containing nitrogen or phosphorus. 

Numerous methods have been pubUshed for the determination of trace amounts of tellurium (33—42). Instmmental analytical methods (qv) used to determine trace amounts of tellurium include atomic absorption spectrometry, flame, graphite furnace, and hydride generation inductively coupled argon plasma optical emission spectrometry inductively coupled plasma mass spectrometry neutron activation analysis and spectrophotometry (see Mass spectrometry Spectroscopy, optical). Other instmmental methods include polarography, potentiometry, emission spectroscopy, x-ray diffraction, and x-ray fluorescence. 

The majoiity of the various analyte measurements made in automated clinical chemistry analyzers involve optical techniques such as absorbance, reflectance, luminescence, and turbidimetric and nephelometric detection means. Some of these ate illustrated in Figure 3. The measurement of electrolytes such as sodium and potassium have generally been accomphshed by flame photometry or ion-selective electrode sensors (qv). However, the development of chromogenic ionophores permits these measurements to be done by absorbance photometry also. 

The detection and determination of traces of cobalt is of concern in such diverse areas as soflds, plants, fertilizers (qv), stainless and other steels for nuclear energy equipment (see Steel), high purity fissile materials (U, Th), refractory metals (Ta, Nb, Mo, and W), and semiconductors (qv). Useful techniques are spectrophotometry, polarography, emission spectrography, flame photometry, x-ray fluorescence, activation analysis, tracers, and mass spectrography, chromatography, and ion exchange (19) (see Analytical TffiTHODS Spectroscopy, optical Trace and residue analysis). 

Adiabatic flame temperatures agree with values measured by optical techniques, when the combustion is essentially complete and when losses are known to be relatively small. Calculated temperatures and gas compositions are thus extremely useful and essential for assessing the combustion process and predicting the effects of variations in process parameters (4). Advances in computational techniques have made flame temperature and equifibrium gas composition calculations, and the prediction of thermodynamic properties, routine for any fuel-oxidizer system for which the enthalpies and heats of formation are available or can be estimated. 

Optical UV scanners or flame rods should be used because of the speed of response. 

Fick s law 592 Filter funnel 102 Filter papers 115 folding of, 116 incineration of, 120, 121 macerated, 450 quantitative, (T) 116 Filter pulp 450 Filtering crucibles 102 Filters, optical 661 Filtration 102, 106, 115 accelerated, 450 technique of, 116, 117 with filter papers, 116 with filtering crucibles, 117 Flame emission spectroscopy 779, 797 background correction, 795 elementary theory of, 780 D. of alkali metals by, 812... 

Flame Photometric Detector3 With the flame photometric detector (FPD), as with the FID, the sample effluent is burned in a hydrogen/air flame. By using optical filters to select wavelengths specific to sulfur and phosphorus and a photomultiplier tube, sulfur or phosphorus compounds can be selectively detected. 

Methanol is a dangerous fire hazard when exposed to heat or flame, and a moderate expl hazard when exposed to flame. It is a dangerous disaster hazard upon exposure to heat or flame, and can react vigorously with oxidizing materials. Methanol possesses distinct narcotic props, and is also a slight irritant to the mucous membranes. Its main toxic effect is exerted upon the nervous system, particularly the optic nerves and possibly the retinae. In the body the products formed by its oxidn are formaldehyde and formic acid, both of which are toxic. Because of the slowness with which it is eliminated, methanol should be regarded as a cumulative poison (Ref 5)... 

Rimai L., Marko K.A., and Klick D., Optical study of a 2-dimensional laminar flame Relation between temperature and flow-velocity fields, Proc. Combust. Inst., 19 259-265,1982. 

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