Hall electrolytic conductivity

ECD = electron capture detector FID = flame ionization detection GC = gas chromatography HECD = Hall electrolytic conductivity detector HRGC = high-resolution gas chromatography HSD = halogen-specific detector H2SO4 = sulfuric acid MS = mass spectrometry NR = not reported PID = photoionization detection UV = ultraviolet detection... 

The most widely used element-selective electrochemical detector is the Hall electrolytic conductivity detector (HECD) [98,116,206]. This is an improved version of an earlier design by Coulson [207,208]. In both detectors the reaction products are swept from the furnace into a gas-liquid contactor trtiere they are mixed with an appropriate solvent. The liquid phase is separated from insoluble gases in a gas-liquid separator and then passed through a conductivity cell. The Coulson detector employed a... 

Figure 3.16 Schenatic diagran of a Hall electrolytic conductivity detector with an expanded view of the bipolar pulsed differential conductivity cell.

The Bellar et al. [219] purge and trap method has been applied to the determination of vinyl chloride in seawater. Using the Hall electrolytic conductivity detector, no response was obtained for the acetone used to prepare the vinyl chloride standard solution. 

The best sensitivity for 1,2-dibromoethane quantification is obtained by either electron capture detector (ECD) or Hall electrolytic conductivity detector (HECD) in the halide detection mode, since these detectors are relatively insensitive to nonhalogenated species and very sensitive to halogenated species. Another common detection device is a mass spectrometer (MS) connected to a GC. The GC/MS combination provides unequivocal identification of 1,2-dibromoethane in samples containing multiple components having similar GC elution characteristics (see Table 6-2). To date, GC equipped with either ECD or HECD has provided the greatest sensitivity for detecting... 

Eopez-Avila V, Heath N, Hu A. 1987. Determination of purgeable halocarbons and aromatics by photoionization and Hall electrolytic conductivity detectors connected in series. J Chromatog Sci 25 356-363. 

Gluck, S. J. The Response of the Model 700A Hall Electrolytic Conductivity Detector to Sulfur Containing Molecules Symposium On Environmental Analytical Chemistry, Brigham Young University, Paper IF, 1980. 

Hall Electrolytic Conductivity Detector In halogen mode responds to halogens 10° 1 x 1013 g cl/sec Poor... 

An oven temperature in the range of 200°C and detector and injector temperatures around 300°C and 250°C, respectively, should give good separation, sharpness of peaks, and fast analysis time. Electron capture detector (ECD) is the most commonly used detector for trace level analysis of PCBs by gas chromatography (GC), exhibiting a response to an amount below 0.1 ng PCBs. Thus, on a capillary column, an IDL in the range of 5 pg/L can be achieved. With proper sample concentration steps, a detection level several-fold lower to IDL may be obtained. Other halogen-specific detectors such as Hall electrolytic conductivity detector can also be used to analyze PCBs. 

S. Gluck, Performance of the model 700A Hall electrolytic conductivity detector as a sulfur selective detector., J. Chromatogr. Sci., 20 103-108 (1982). 

Trihalomethanes Liquid- hquid extraction Hall electrolytic conductivity in hydrogen mode Recovery 88-98.6% Low Pg L 1 [539- 541]... 

Chloroanilines, chloronitroanilines N-P specific and Hall electrolytic conductivity [662]... 

Dithiocarbamate -insecticides - Hall electrolytic conductivity in S mode Conversion of -insecticide to carbon disulphide [675]... 

A detector that is especially sensitive to sulphur compounds is critical to the gas-chromatography system. There are three types of detectors that are sensitive to ppb concentrations of sulphur compounds the flame photometric detector (FPD) the Hall electrolytic conductivity detector (HECD) and the photoionisation detector (PID). The advantages and disadvantages of each are summarised in Table 8-II. 

Fig. 8-10. Cross section of Hall electrolytic conductivity detector reactor (from Tracor, 1980b).

Tracor, 1980b. Tracor 700A Hall Electrolytic Conductivity Detector, Operations Manual. Tracor Instr., Austin, Texas, 70 pp. 

Methods for quantifying NDMA in environmental sanples are summarized in Table 6-2. As with the biological samples, in situ artifact formation must be avoided in order to get accurate results from the analysis of environmental sanples (Fisher et al. 1977 Fine et al. 1977a). The three quantification methods that give satisfactory sensitivity for NDMA are alkali flame ionization detector (in the nitrogen mode) (AFID), Hall electrolytic conductivity detector (HECD) in the reductive mode and TEA. 

GC = Gas chromatography MS = mass spectrometry HRGC = High resolution gas chromatography TEA = thermal energy analyzer MPO = nitrogen-phosphorus detector HECD = Hall electrolytic conductivity detector AFID = alkali flame ionization detector EC = electron capture detector NG = not given... 

Hall Electrolytic Conductivity Detector (Hall or ELCD)... 

Since GC instrumentation is available in most analytical laboratories, it has been the principal method of analysis for volatile A -nitrosamines. Many detectors have been coupled to GC for the detection of A -nitrosamines. The conventional flame ionization detector (FID) was initially used but was found to be limited for Ai-nitrosamines. Nitrogen-specific detectors such as the Alkali Hame Ionization (AFID), the Coulson Electrolytic Conductivity (CECD) and Hall Electrolytic Conductivity (HECD) are useful for routine screening. Although the HECD is the most selective, it is not specific to A-nitrosamines and an independent confirmation is necessary for each analysis. The efficiency of common GC detectors for the analysis of A-nitrosamines has been compared by several authors. 

Electrolytic Conductivity Detectors In the Hall electrolytic conductivity detector, compounds containing halogens, sulfur, or nitrogen arc mixed with a reaction gas in a small reactor tube, usually made of nickel. The reaction tube is kept at 85(FC-lO(X) C. The products arc then dissolved in a liquid, which produces a conductive solution. The change in conductivity as a result of the ionic species in the conductance cell is then measured. A typical delector is illustrated in Figure 27-11. 

FIGURE 27-11 Diagram of a Hall electrolytic conductivity detector. (Courtesy of ThermoElectron Corp.)... 

HECD Hall electrolytic conductivity detector (used in GC to analyze halogenated organics generally, volatile organics)... 

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