Carbon Dioxide Detector Tube

A. Pass 100 5 mL of sample, released from the vapor phase of the contents of the container, through a carbon dioxide detector tube (see Detector Tubes under Solutions and Indicators) at the rate specified for the tube. The indicator change extends throughout the entire indicating range of the tube. 

Bacillus subtilis var. including Bacillus amyloliquefaciens), 131, (S3)20 Carbohydrates (Starches, Sugars, and Related Substances), 836 Carbon, Activated, 85, (S 1)115 Carbonate Identification Test, 753 Carbon Dioxide, 87, (S 1)12 Carbon Dioxide Detector Tube, 862 Carbon Monoxide Detector Tube, 862 o-Carboxybenzeneazodimethylaniline Hydrochloride, 861 (R)-3-Carboxy-2-hydroxy-/V,/V,/V-... 

The evolution of carbon dioxide was monitored by gas chromatograph (Hewlett-Packard model 5890) equipped with an HP thermal-conductivity detector and a Hayesep 100-120-mesh packed column (10 m X 3.2 mm). Helium was the carrier gas, and its flow rate was 28 mL/min. In each run, 0.5 mL of the gas mixture in the headspace was withdrawn from the test tube by using a pressure-lock gas syringe and injected into the GC column. The calibration curve was made by acidifying a known amount of potassium bicarbonate in the reaction tube under conditions similar to those of the corresponding experimental conditions. Standard carbon dioxide gas (Supelco) was used to confirm the formation of carbon dioxide. 

Figure 7 Schematic diagram of semipreperative-scale SFC chromatograph 1 carbon dioxide supply 1 a regulator 2 prechiller/heat exchanger 3 SD-1 Varian pump with (7) 200-mLpump head with special check valves 4 modifier reservoir 5 SD-1 modifier pump with (6) 200-mL standard pump heads 8 check valve 9 inlet pressure transducer 10 injection valve 11 check valve to prevent blow-back 12 mixer 13 fluid temperature preconditioner 14 column 15 column oven 16 uv detector 17 outlet pressure transducer 18 back-pressure regulator 1 9 evaporator 20 restrictor 21 trim heater 22 selection valve 23 peak detector 24 bank of collection vessels (or cassette) 25 individual collection tubes/bottles 26 pressure relief valves 27 waste container, waste vent. The manual cassette can be replaced with an automated cassette fed by a robot holding 128, 25 x 150-mm or 338, 16 x 150-mm test tubes, or with 7 large bottles.

On-line analysis of the effluent gases was conducted using a gas chromatograph (Hewlett Packard model 5890 Series H), equipped with FID and TCD detectors. A DB-624 fused silica capillary column was used for the hydrocarbon separation. The carbon monoxide and carbon dioxide were separated using molecular sieves (5A) and Hayesep R columns. Tlie effluent gases were analyzed for the unconverted VOCs, partial oxidation products such as chloroform and 1,1,2-trichlorocthanc, and total oxidation products (CO and COj). The HO and Clj analysis was performed using Drager tubes. The total conversion is based on total cartoon atoms in the feed. 

Relatively inexpensive portable colorimetric indicators are now commonly used to detect the presence of a variety of contaminant gases in the atmosphere. These are normally specific for one or perhaps a series of gases. For example, the NBS colorimetric detector uses an indicator tube that contains a 15-mm section of yellow palladous silico-molybdate gel the gel changes color when exposed to carbon monoxide at concentrations as low as 0.001 vol. % in air. Figure 52 shows one version of a commercial unit used for carbon monoxide as well as carbon dioxide, the unsaturated hydrocarbons, and a variety of other gases this unit can also be used to determine the approximate concentrations of contaminants in liquid oxygen. Precise determinations can be made with a variety of analytical tools, including infrared... 

---