Emissivity detector application

Wylie, P.L. and Quimby, B.D. (1989) Applications of gas chromatography with an atomic emission detector. J. High Resol. Chromatogr. 12, 813-818. 

There are many GC detectors available although the flame ionisation detector remains the most widely used and the most widely applicable to quality control of pharmaceutical products. However, newer detectors such as the plasma emission detector for analysis of trace impurities or the GC-FTIR detector for the structural characterisation of components in mixtures are becoming increasingly important. 

Eijkel, J.C.T., Stoeri, H., Manz, A.J., An atmospheric pressure dc glow discharge on a microchip and its application as a molecular emission detector J. Anal. Atom. Spectrom. 2000, 15, 297-300. 

M. Zerezghi, K. Mulligan, et al., Application of a rapid scanning plasma emission detector and gas chromatography for multi-element quantification of halogenated hydrocarbons, J. Chromatogr. Sci., 22 348-352(1984). 

F. David and P. Sandra, Comparison of the Sensitivity of the Flame Photometric Detector and the Atomic Emission Detector for the Analysis of Thiazone, Hewlett-Packard Application Note 228-136, Publication No. (43) 5091-1933E, USA, August 1991. 

Because of its low specificity and sensitivity flame ionisation detection (FID) can only be used in the analysis of standard substances [37]. The same limited application is envisaged for the method with the microwave-induced plasma emission detector, which is not sensitive enough for environmental samples [2]. 

The emissivity detector or what is now known as the Flame Photometric detector (FPD) was originally developed by Grant (9) in 1958 but was not produced commercially at the time as it could not compete in sensitivity with the ionization detectors. The emissivity detector, however, has some unique properties that can make its response quite specific, thus giving it certain unique areas of application. Grant originally employed it to differentiate aromatic from paraffinic hydrocarbons in coal tar products by measuring the luminosity that the aromatic nucleus imparted to the flame. 

Many detectors have been used to detect pesticides and herbicides in SFC. Among these detectors, the flame ionization detector (FID) is most commonly used for detection of a wide range of pesticides and herbicides, with a detection limit ranging from 1 ppm (for carbonfuran) to 80 ppm (for Karmex, Harmony, Glean, and Oust herbicides). The UV detector has frequently been used for the detection of compounds with chromophores. The detection limit was as low as 10 ppt when solid-phase extraction (SPE) was on-line coupled to SFC. The mass spectrometric detector (MSD) has also been used in many applications as a universal detector. The MSD detection limit reached 10 ppb with on-line SFE (supercritical fluid extraction)-SFC. Selective detection of chlorinated pesticides and herbicides has been achieved by an electron-capture detector (ECD). The limit of detection for triazole fungicide metabolite was reported to be 35 ppb. Other detectors used for detection of pesticides and herbicides include thermoionic, infrared, photometric, and atomic emission detectors. 

Element selective detectors Element selective detectors applicable in pesticide residue analysis include electron capture detector (ECD), electrolytic conductivity detector (ELCD), halogen-specific detector (XSD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD), pulsed flame photometric detector (PEPD), sulfur chemiluminescence detector (SCD), and atomic emission detector (AED). To cover a wider range of pesticide residues, a halogen-selective detector (ECD, ELCD, XSD) in conjvmction with a phosphorus- (NPD, FPD), nitrogen- (NPD), and/or sulfur-selective detector (FPD, SCD) is commonly used. A practical approach is to spht the column flow to two detectors that reduces the number of injections however, the reduced amoimt of analyte that reaches the detector must be considered. 

Online applications are by far the most important utilization of diode array spectrometry. High-performance liquid chromatography, supercritical fluid chromatography, capillary electrophoresis, and flow-injection techniques produce enhanced sensitivity and structure-related information due to coupling with diode-array-based detectors. Emission of the microwave-induced plasma generated in atomic emission detectors for capillary gas chromatography is also analyzed by means of UV-Vis diode array instruments. 

Various workers (Reamer et al, and Quimby et al ) have examined the applicability of helium in microwave glow discharge detectors for the detection of organolead compounds leaving a gas chromatographic column. A microwave emission detector (MED) was firsi described by McCormack et al. ... 

Similarly, most IR detector applications depend on emission directly from the source of interest, so you may hear the term thermal emitter used interchangeably with IR source . Again, the two phrases are strongly related, but not synonymous. 

Hewlett Packard Technical Bulletins and Application Notes on the HP 5921A Atomic Emission Detector for GC, 1988-90, Hewlett Packard Corporation, Avondale, PA. 

In Dynamic Spatial Reconstructor at the expense of use 2D matrix of detectors there was the opportunity to use a divergent cone beam of source emission. This system had a number of lacks. In particular the number of projections is rigidly limited by the number of x-ray sources. The dispersion of source emission results in errors of data collected.. However the system confirmed basic advantages of application of conic beams and 2D matrices of detectors for collecting information about 3D object. 

The Institute has many-year experience of investigations and developments in the field of NDT. These are, mainly, developments which allowed creation of a series of eddy current flaw detectors for various applications. The Institute has traditionally studied the physico-mechanical properties of materials, their stressed-strained state, fracture mechanics and developed on this basis the procedures and instruments which measure the properties and predict the behaviour of materials. Quite important are also developments of technologies and equipment for control of thickness and adhesion of thin protective coatings on various bases, corrosion control of underground pipelines by indirect method, acoustic emission control of hydrogen and corrosion cracking in structural materials, etc. 

Quantitative accuracy and precision (see Section 2.5 below) often depend upon the selectivity of the detector because of the presence of background and/or co-eluted materials. The most widely used detector for HPLC, the UV detector, does not have such selectivity as it normally gives rise to relatively broad signals, and if more than one component is present, these overlap and deconvolution is difficult. The related technique of fluorescence has more selectivity, since both absorption and emission wavelengths are utilized, but is only applicable to a limited number of analytes, even when derivatization procedures are used. 

The purpose of this work is to demonstrate that the techniques of quantum control, which were developed originally to study atoms and molecules, can be applied to the solid state. Previous work considered a simple example, the asymmetric double quantum well (ADQW). Results for this system showed that both the wave paeket dynamics and the THz emission can be controlled with simple, experimentally feasible laser pulses. This work extends the previous results to superlattices and chirped superlattices. These systems are considerably more complicated, because their dynamic phase space is much larger. They also have potential applications as solid-state devices, such as ultrafast switches or detectors. 

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