Nitrogen carrier gas

Shakhtman and coworkers67 carried out gas-solid chromatographic separation of cis/trans pairs, including l-phenylsulphonyl-2-(phenylthio)ethene and ethyl-w-styryl sulphone they used a graphitized C-black column at 230 °C, nitrogen carrier gas and FID. 

The signal was recorded on a Hewlett Packard Integrator Model 3393A Integrator. Samples were injected onto a 30 m megabore column coated with 1.5 micron DB-5 purchased from J W Scientific. The flow of nitrogen carrier gas was maintained at 30 cc/min. The column was equilibrated at 150°C. On injection of the sample, this temperature was maintained for five minutes followed by a programmed increase at a rate of 8°C/min. to a maximum of 300°C, which was maintained for 30 minutes. 

Flame photometric detector fitted with a 394-nm sulfur-specific filter, temperature 150 °C Nitrogen carrier gas, 50mLmin ... 

Figure 2.3 Coluon efficiency test for a 1.5 m x 2 ra i.D. packed column coated with 10% (w/w) OV-101 on chromosorb P-AH (100-120 mesh) at 100 C with a nitrogen carrier gas flow rate of 30 Bl/nin. The test sample is a mixture of n-alkanes.

Carbon-coating is an effective way to improve the performance of electrode materials for lithium batteries, particularly with graphites [11-14], It is also known to aid in the surface conductivity for LiFeP04 as a cathode material [27], There are many ways to coat powders with carbon, but in this study, we have chosen to decompose a hydrocarbon vapor of propylene in a nitrogen carrier gas at a moderate temperature of 700 °C. Criteria for using this process include a material that is stable at this temperature and under a reducing environment. 

The decomposition of gaseous di-t-butyl peroxide in the presence of a nitrogen carrier gas (D) has been studied near 481 K in a CSTR (Mulcahy Williams, Austral J Chem 14 534, 1961). 

In the Philips total oxygen demand meter the zirconium oxide is specially prepared and is in the form of two series connected tubes or cells through which a nitrogen carrier gas is allowed to flow. Each cell is provided with two pairs of annular (internal and external) electrodes and the whole assembly is maintained at about 600°C. 

One pair of electrodes conduct an electrical current through the zirconium oxide wall, thereby transporting oxygen from the external atmosphere through the cell wall, into the nitrogen carrier gas. The other pair is used to measure the potential difference over the zirconium oxide. 

A preset quantity of oxygen is admitted to the nitrogen carrier gas (whose pressure and flow rate is controlled) via the dosing cell. The quantity of oxygen is controlled by a range selector. 

Gas chromatographic data was obtained on a Tracor Model 220 gas chromatograph equipped with a Varian Model 8000 autosampler. The analysis column was a 1.7 m "U column, 4 mm id, filled with 3% SP-2250 packing (Supelco, Inc., Bellefonte, PA) held at 200 C. The injection temperature was 250 and the nitrogen carrier gas flow rate was 60 mL/min. The detector temperatures were 350 for electron capture and 190 for flame photometric. Detector signals were processed by a Varian Vista 401 which gave retention times and peak areas. 

Fig. 17 Concentrations of gas-phase species at partial equilibrium (see text) as a function of temperature for 2% DMTC, 20% O2, and 5% H2O in nitrogen carrier gas at 1 atm total pressure...

Moilanen et al. (1978) observed that it was stable to irradiation when it was in a nitrogen carrier gas, indicating that molecular oxygen is involved in the photochemical decomposition they suggest that 02 may add to a biradical formed from the chloropicrin upon light absorption but that 02 is regenerated in the decomposition of the adduct. 

Urine (5 ml) urine spiked with 0.2% (v/v) isopropylamine is placed in a screw-capped 15-ml vial [28]. Pelleted potassium hydroxide (3 g) is added before sealing the vial with an airtight polytetrafluoroethylene-lined septum cap. Potassium hydroxide raises the pH of the sample to ensure that the amines are present as volatile bases. The vial is heated in an aluminium block at 90 C for 20 min. While still in this block, 2 ml head-space gas is withdrawn through the septum with a disposable syringe and injected immediately on the gas chromatography column. The operating temperatures of the column, injector port and detector unit are 70 C isothermal, 150 C and 200 C, respectively, with nitrogen carrier gas at 60 ml/min. This allows quantification of TMA and other amines. TMA N-oxide is measured after quantitative reduction into TMA. For this, titanous chloride (30%, w/v 0.2 ml) is added to 2 ml urine in a screw-capped vial and incubated for 30 min at room temperature. The sample is then diluted ten-fold with distilled water and analysed as described above. The result represents the sum of TMA and TMA N-oxide present in the sample. 

GAS CHROMATOGRAPHIC PARAMETERS. A gas chromatograph equipped with a hydrogen flame detector is used. Flame ionization detection allows the use of samples containing water. The column is stainless steel (6 ft x 0.25 in. o.d.) packed with 30° Carbowax 20 M on acid-washed 60/80 mesh Chromosorb W. The column was conditioned overnight at 180°C with a flow of nitrogen carrier gas. 

Note. (1) The reaction may be monitored by observing the diminution of carbonyl absorption in the infrared spectrum of successive samples withdrawn from the organic phase, after allowing the dichloromethane to evaporate from a portion placed on a sodium chloride plate. Alternatively samples of the reaction medium may be analysed by g.l.c. using a 10 per cent Carbowax column on Chromosorb W held at 150 °C with a nitrogen carrier gas flow rate of 40ml/minute benzaldehyde has tR 2 minutes and phenyloxirane has tR 2.75 minutes. 

The Frank and Demint [200] method is directly applicable to water samples. After addition of sodium chloride (340g IT1) and aqueous hydrochloric acid (1 1) to bring the pH to 1, the sample was extracted with ethyl ether and the organic layer was then extracted with 0.1M sodium bicarbonate (saturated with sodium chloride and adjusted with sodium hydroxide to pH8). The aqueous solution adjusted to pHl with hydrochloric acid was extracted with ether and after evaporation of the ether to a small volume, Dalapon was esterified at room temperature by addition of diazomethane (0.5% solution in ether) and then applied to a stainless steel column (1.5m/3mm) packed with Chromosorb P (60-80 mesh) pretreated with hexamethyldisilazane and then coated with 10% FFAP. The column was operated at 140°C, with nitrogen carrier gas (30mL muT1) and electron capture detection. The recovery of Dalapon ranged from 91 to 100% the limit of detection was O.lng. Herbicides of the phenoxyacetic acid type did not interfere trichloroacetic acid could be determined simultaneously with Dalapon. 

He Pulses in Nitrogen Figure 1. illustrates a typical response curve (continuous line) obtained for a 1 second pulse of He in a nitrogen carrier gas stream. Using the moment method (12), the effective diffusion coefficient for He is 0.137 cm /sec. To compare this with steady state data, it is necessary to make use of equation (3). 

Dried residues of extracts, processed from volumes of urine containing 25 mg of creatinine, were dissolved in 50 yl of BSTFA (containing 1% TMCS) in dimethylfor-mamide (1 1) and heated at 70°C for 5 minutes. Five microliter aliquots were injected into a 180 cm x 0.2 cm ID pyrex column packed with 1.5% OV-17 on 100/120 mesh HP chromosorb G held isothermally at 275°C with nitrogen carrier gas flow of 30 ml/minute. Each sample was automatically screened by PBM for A -THC and seven of its metabolites (cf. Figure 9) using assay programs consisting of 10 carefully selected characteristic ions for each compound (7). 

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