Detectors chromatographic

Loop injector Sample in Chromatographic Detector Recorder... 

It should not be concluded that the above examples of the evaluation of qualitative and quantitative data comprise an exhaustive analysis of this particular set of LC-MS data. They have been included primarily for those not used to the analysis of mass spectral data, to show the principles involved, and to demonstrate how powerful the mass speedometer can be as a chromatographic detector. 

General detector A (chromatographic) detector which responds to all compounds reaching it. 

Aqueous distillates are extracted, usually with dichloro-methane (DCM), concentrated to small volumes, generally in a Kuderna-Danish evaporator, and examined by gas chromatography (GC) using a specific detection system. Additional chromatographic cleanup may be required, depending on the complexity of the sample and specificity of the chromatographic detector. 

Chromatographic Detectors Design, Function, and Operation, Raymond P W. Scott... 

R. P. H. Scott, "Liquid Chromatographic Detectors", Elsevier, Ansterdara, 1986. 

Figure 1.18 Methods for calculating short- and long-ten noise and drift for chromatographic detectors.

H. Dressier, "Selective Gas Chromatographic Detectors", Elsevier, Amsterdam, 1986. 

The flame ionization detector Is the most popular of the flame-based detectors. Apart from a reduction in sensitivity compared to expectations based on gas chromatographic response factors [138] and incompatibility with the high flow rates of conventional bore columns (4-5 mm I. 0.), the flame ionization detector is every bit as easy to use in SFC as it is in gas chromatography [148,149]. It shows virtually no response to carbon dioxide, nitrous oxide and sulfur hexafluoride mobile phases but is generally incompatible with other mobile phases and mixed mobile phases containing organic modifiers except for water and formic acid, other gas chromatographic detectors that have been used in SFC include the thermionic ionization detector (148,150], ... 

The first classification is based on the nature of the detector response. Table 4.7 ranks several chromatographic detectors as specific and nonspecific. A nonspecific or universal detector responds to all solutes present in the mobile phase and this performance makes it a... 

Table 4.7 Some specific and nonspecific chromatographic detectors...

Table 4.8 shows some frequently used element selective chromatographic detectors (ESDs) and Table 4.9... 

Table 4.8 Main element specific chromatographic detectors (ESDs)...

Advantages and disadvantages of chromatographic detectors and tandem systems are given in Table 4.13, whereas Table 4.14 gives a breakdown of the various detectors over the main chromatographic techniques. Simultaneous detection is possible, e.g. SCD/CLND. 

Table 4.14 Characteristics of chromatographic detectors and tandem systems...

As SFC provides gaseous sample introduction to the plasma and thus near-100 % analyte transport efficiency, coupling SFC with plasma mass spectrometry offers the potential of a highly sensitive, element-selective chromatographic detector for many elements. Helium high-efficiency microwave-induced plasma has been proposed as an element-selective detector for both pSFC and cSFC [467,468] easy hyphenation of pSFC to AED has been reported [213]. 

The main detectors used in AES today are photomultiplier tubes (PMTs), photodiode arrays (PDAs), charge-coupled devices (CCDs), and vidicons, image dissectors, and charge-injection detectors (CIDs). An innovative CCD detector for AES has been described [147]. New developments are the array detector AES. With modem multichannel echelle spectral analysers it is possible to analyse any luminous event (flash, spark, laser-induced plasma, discharge) instantly. Considering the complexity of emission spectra, the importance of spectral resolution cannot be overemphasised. Table 8.25 shows some typical spectral emission lines of some common elements. Atomic plasma emission sources can act as chromatographic detectors, e.g. GC-AED (see Chapter 4). 

The high sensitivity and selectivity of some gas chromatographic detectors are used to advantage in the measurement of organic mercury compounds. In the simplest approach, methyl mercury is extracted from seawater and converted to the iodide for electron capture gas chromatography [74],... 

M Dressier. Selective Gas Chromatographic Detectors. Amsterdam Elsevier, 1986, pp 1-319. 

The nature of a supercritical fluid enables both gas and liquid chromatographic detectors to be used in SFC. Flame ionization (FID), nitrogen phosphorus (NPD), flame photometric (FPD) GC detectors (p. 100 etseq.) and UV and fluorescence HPLC monitors are all compatible with a supercritical fluid mobile phase and can be adapted to operate at the required pressures (up to several hundred bar). A very wide range of solute types can therefore be detected in SFC. In addition the coupled or hyphenated techniques of SFC-MS and SFC-FT-IR are attractive possibilities (cf. GC-MS and GC-IR, p. 114 el seq.). 

Development of Mass Spectrometry as Liquid Chromatographic Detector.120... 

Common GC mobile phases (see Table 13.2) are hydrogen, argon, helium, nitrogen, and air. Helium and nitrogen are the most commonly used. Because gas chromatographic detectors are extremely sensitive and it is desirable to keep the noise level as low as possible, it is always advisable to use very high-purity gas as the mobile phase. 

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