Hydrogen flame temperature detector

Procedure (See Chromatography, Appendix IIA.) Use a suitable gas chromatograph equipped with a hydrogen flame-ionization detector, and a silanized 1-m x 4-mm (id) glass column, or equivalent, packed with 90- to 100-mesh Anakrom ABS, or equivalent, containing 7.5% Carbowax 20M and 2% potassium hydroxide, or equivalent. Maintain the column at 190° (isothermal). Set the injection point temperature to 200° and the detector temperature to 250°. Use nitrogen as the carrier gas, with a flow rate of 50 mL/min. 

Nitrogen was used as carrier gas at flow rate between 20 and 30ml/min. Using the hydrogen flame ionization detector, the retention times of the alkyl selenium compounds were determined on each of the three columns at column temperature, within the range of 35-175°C. The injector temperature was set at 50 to 100°C higher than the column temperature. One per cent solutions of each selenium compound in carbon disulphide were used for the determinations, as carbon disulphide gives very little response with this detector system. 

Fig, 220. The separation of alkyl selenium compounds on a poly-metaphenylether column with hydrogen flame ionization detector. Column temperature 150 C., injector temperature 225°C., nitrogen carrier gas flow rate 25ml/min.,... 

Ethylene hydrogenation was carried out in a once-through flow reactor. The effluent gas mixture was analyzed with an online gas chromatograph (Hewlett-Packard HP 6890) equipped with an AI2O3 capillary column and a flame ionization detector. Testing conditions included Phydrogen = 200 Torr, Pethyiene = 40 Torr, catalyst mass of 10 to 20 mg and temperature varied from -50 to -25°C. 

Gas chromatograms of fully hydrogenated fish triglycerides on a 1.83-m glass column, 3% JXR on 100/120 mesh Gas Chrom Q, flame Ionization detector injector 350°C detector 320-360 C, temperature programmed at 4°C/min (210-375°C) (7). 

Gas Chromatograph Conditions. The GC was a VARIAN 6000 with a flame ionization detector. The injection port was heated at 200°, the detector at 250°. The detector range was 10-12 AFS, attenuation 64 except as noted. The column was 25m X 0.32mm fused silica DB5 with a 1.0 micron film thickness (bonded SE54, J W Scientific, Rancho Cordova, CA). The carrier gas was hydrogen at 47 cm/s. The column was temperature programmed from an initial temperature of 35 C, held for 4 min., to a final temperature of 200 C at 4°C/min. 

Organic compounds ionize when burned in a hydrogen air flame. If two electrodes at a potential difference of approximately 150 V are inserted into this flame, differences in conductivity of the flame can be measured as the solutes elute from the column and are burned. This isthe principle on which the flame ionization detector is based. In the usual flame detector, the column effluent ismixed with hydrogen. This mixture is fed into the flame jet of the detector. The jet is a thin-walled stainless steel tube that also acts as one electrode. The other electrode is a fine platinum wire held above the jet. The response of this detector is practically instantaneous. It is not affected as much as the thermal conductivity detector is by changes in temperature and carrier gas flow rate. It is very sensitive and can detect approximately 10 °-10 mol solute. 

The feedstocks (straight-mn naphtha (SRN) and a blend of SRN and hydrocracked naphtha) and hydrotreated products were analysed by ASTM methods for density, carbon, hydrogen, hydrocarbon and boiling point distribution. Total sulfur was determined by ASTM D-4045 method, mercaptan sulfur by the potentiometric method (ASTM D-3227 and UOP-212), disulfides by the UOP-202 method, polysulfides by polarography [1], and elemental sulfur by the UOP-286 method. The Perkin-Elmer gas chromatograph (Model 8700), equipped with a flame photometric detector (GC/FPD) and a DB-1 fused silica capillary column (30 m x 0.53 mm), was used for identification of individual sulfur compounds [2-6]. The sensitivity of the GC/FPD technique was maximized by optimizing the gas flow rates and temperature programming as presented elsewhere [1]. 

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