University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Gas

Classification: Gas

Citations 12

"Determination Of Potassium In Gasoline And Lubricating Oils By A Flow Injection Technique With Flame Atomic Emission Spectrometric Detection"
Anal. Chim. Acta 1990 Volume 234, Issue 2 Pages 439-444
Gavin E. Roscoe and Richard Miles, Colin G. Taylor

Abstract: Petroleum spirit (b.p. 100°C to 120°C or 120°C to 160°C) is used as carrier stream for gasoline or lubricating oil (the latter diluted 100-fold). The stream is transferred via PTFE tubing and aspirated into the photometer. For gasoline, the carrier also acts as the fuel supply to the flame. The calibration graph (peak area) is rectilinear up to 20 µg kg-1 of K. Gasoline volatility affects response so sample and standard should be matched. Precision at 10 mg kg-1 is 3%. Oxygenates and halogenated hydrocarbons do not interfere, and recoveries are ~100%. Sample throughputs are 40 and 100 h-1 for gasoline and oil, respectively. The method may be applied in the determination of other alkali and alkaline-earth metals in lubricating oils and fuels.
Potassium Metals, alkali Metals, alkaline earth Spectrophotometry Interferences

"Application Of Wet Chemistry Techniques To Process Analysis And Control"
Anal. Chim. Acta 1990 Volume 238, Issue 1 Pages 161-170
Rajko Puzic

Abstract: The application of automatic titrators and ion chromatographs to the compositional analysis of caustic and alkanolamine gas sweetening solution is described. Comparisons with other techniques such as flow injection analysis and UV and near-IR spectrometry are made and pertinent features and benefits of each are discussed.
HPIC Titrations Review Process control

"Determination Of Carbon Dioxide In Gaseous Samples Using A Monosegmented Flow System And Conductimetric Detection"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 223-229
Maria do Carmo Hespanhol da Silva, Jarbas José Rodrigues Rohwedder and Celio Pasquini*

Abstract: The monosegmented approach to flow analysis was employed for determination of low contents (100-1000 ppmv) of CO2 in gaseous samples. The front bubble of the flow pattern constitutes the gaseous sample. The sample is pumped through a glass tube (2 mm i.d., 80 cm long) by deionised water. The film of water present in the tube wall absorbs the CO2 present in the sample. The liquid monosegment collects, by convection movement of the fluid, the layer containing the partially ionized CO2, while the second bubble restricts the dispersion of the collected specimens. The conductivity of the liquid monosegment is monitored at the end of the glass tubing and is proportional to the CO2 content in the gaseous sample. The system has been optimized for determination of CO2 in the 50-1000 ppmv range. For the experiment, 100 µL of sample is employed and the system can perform 60 determination per hour. The relative standard deviation for the signals of standards in the 100-900 ppmv range was ~3%. Comparison with a gas chromatographic method revealed a mean relative difference of 7% for samples containing CO2 in the 20-700 ppmv range. The system employing conductimetric detection does not employ any reagent, is very simple and suitable for field monitoring of CO2 present in the atmosphere, indoors and outdoors.
Carbon dioxide Conductometry

"Reverse Dual Phase Gas Diffusion Flow Injection Analysis"
Talanta 1993 Volume 40, Issue 12 Pages 1961-1966
K. J. Smith and G. E. Pacey

Abstract: For the determination of CO2 in gases, the gas stream (62 ml/min) was passed in front of a Celgard 2500 membrane. On the other side of the membrane, the receptor solution flow was stopped for 15 s, while the CO2 diffused across the membrane. The receptor solution contained 10 mL of 0.1% cresol red in 2 mM NaOH, diluted to 1 l with 1 mM carbonate buffer of pH 8.85 which was pumped at 1.9 ml/min to the detector at 430 nm. The membrane efficiency was 30.6%. The calibration graph was linear for 6.7-197 g/m3 of CO2 with a detection limit of 2 g/m3. Other calibration ranges could be obtained by varying the buffer concentration. A similar method was devised for the determination of hydrazine in air with a gas flow rate of 225 ml/min; the receptor solution containing 0.1 g/l of bromophenol blue adjusted to pH 3.9 with 0.5 M HCl was stopped for 20 min and measurements were made at 460 nm. The membrane efficiency was 17.4%. The calibration graph was linear for 0.035-0.14 ppm of hydrazine with a detection limit of 0.01 ppm. The sensitivity of the membrane decreased slowly over a 6 day period. Interferences by NH3, monomethylhydrazine and 1,1-dimethylhydrazine are discussed.
Carbon dioxide Reverse Gas diffusion Membrane Interferences Celgard

"Direct Detection Of Vacuum Ultra-violet Radiation Through An Optical Sampling Orifice: Determination Of Non-metals In Gaseous Samples By Inductively Coupled Plasma Atomic-emission Spectroscopy"
Anal. Chem. 1988 Volume 60, Issue 1 Pages 23-26
Bryant R. LaFreniere, R. S. Houk, Daniel R. Wiederin, and Velmer A. Fassel

Abstract: Mixtures of SF6, CCl2F2 and/or CBrF3 in Ar as transport gas were introduced into the axial channel of an ICP from a flow injection system fitted with various sample loops on the injection valve. The arrangement (illustrated) had minimum dead volume (~40 µL). A copper cone with orifice (Ibid., 1987, 59, 2276) was used to sample the vacuum UV emission from the plasma. Detection limits for Br, C, Cl and S were 50, 30, 80 and 20 pg, respectively, with coefficient of variation typically 2%, similar to the limits achieved previously by AES with a He plasma.
Carbon Bromine Chlorine Sulfur Spectrophotometry Method comparison

"A Sensitive Probe For Oxygen Sensing In Gas-mixtures, Based On Room-temperature Phosphorescence Quenching"
Microchim. Acta 1995 Volume 121, Issue 1-4 Pages 51-61
Rosana Badía, Marta E. Díaz-García and Alfredo García-Fresnadillo

Abstract: The dye Erythrosine B (which gives room-temperature phosphorescence, RTP) has been covalently bound to a silica-based amino-functionalized exchanger. The resulting material turned out to be extremely useful as a luminescent probe for oxygen. The photochemical properties and the analytical performance of the RTP probe have been studied by use of a gas flow injection analysis system, which incorporates a convenient exponential dilution chamber for gas sample introduction. The possible origin of the non-linear Stern-Volmer quenching response observed is thoroughly discussed in terms of the quenching and lifetimes. The proposed sensing material is particularly suitable for measuring oxygen in gas mixtures at extremely low concentrations. The detection limit attained was 0.00006% (0.6 ppm) of oxygen in dry argon (making the system one of the more sensitive opto sensors for oxygen published so far). A typical precision of±0.2%, at the 0.025% oxygen level, was achieved. Response times were less than 2 s for full signal change and no hysteresis effects were noticed. A possible mechanism for the observed oxygen RTP quenching in the new sensing material is proposed. (17 References)
Oxygen, molecular Phosphorescence Exponential dilution Mixing chamber Optosensing Quenching

"Flow Injection Analysis Of Inorganic Pollutants In Gaseous Phase With Piezoelectric Detection. 1. Verification Of Principal Experimental Parameters Affecting The Detector Response"
Sens. Actuat. B 1992 Volume 9, Issue 1 Pages 33-39
Marek Trojanowicz and Tadeusz Krawczyski vel Krawczyk

Abstract: Two commercially available piezoelectric quartz crystal detectors were coated with five compounds sensitive to SO2 and NH3 and were tested as sensors in the flow injection analysis - detector system as described by Kamarkar and Guilbault (Anal. Chim. Acta, 1974, 71, 419). The optimum parameters (described) for detectability, stability and reproducibility were derived. Piezoelec. quartz crystal detectors with several coating materials sensitive to SO2 and NH3 are used as model sensors for the optimization of a flow injection measuring system with a gaseous carrier. As factors affecting the quality of detector response, the amt. of coating material and its distribution on the quartz oscillator surface, the composition, flow rate and purity of the gaseous carrier, the design of the flow-through detector, the temperature and the injection volume are considered. The experimental data obtained illustrate the significance of careful optimization of these parameters for the detectability, stability and reproducibility of flow injection analysis in the gaseous phase with piezoelec. detection.
Ammonia Sulfur dioxide Piezoelectric crystal Optimization

"Rapid, Automated Analysis Of Carbon-13 And Oxygen-18 Of Carbon Dioxide In Gas Samples By Continuous-flow, Isotope Ratio Mass Spectrometry"
Biol. Mass Spectrom. 1991 Volume 20, Issue 11 Pages 724-730
S. J. Prosser, S. T. Brookes, A. Linton, T. Preston

Abstract: An automated continuous-flow system is described (diagram given). Breath is collected in either Vacutainers or Exetainers placed in an autosampler. The sample gas is flushed out of the container into a He flow which is passed through a drying tube containing MgClO4 and then to a GC column (18 in x 0.25 in) of Carbosieve-G operated at 60°C to 120°C. The carrier gas containing the separated CO2 is passed to the ion source of a mass spectrometer. The system is evaluated by determining isotope ratios of 13C:12C in breath CO2, 18O:16O in water, 18O:16O in breath CO2 contaminated with N2O.
Carbon-12 Carbon-13 Oxygen-16 Oxygen-18 GC Mass spectrometry Automation Carrier gas Heated reaction Isotope ratio

"Conductimetric Gas Separation-flow Injection Determination Of Ammonia In Gaseous Process Streams"
Collect. Czech. Chem. Commun. 1997 Volume 62, Issue 4 Pages 609-619
Vlastimil KUBAN

Abstract: The membrane separation technique is employed for a selective determination of ammonia in gaseous samples. The gases and purified air were sampled into the outer part of a membrane device with poly(vinylidene difluoride) microporous membranes (0.56 µm pore size, 1.2 mm i.d., active length 2 or 10 cm), with acceptor streams flowing inside the membrane in the continuous-flow mode. The ammonium ions were fed directly into the conductivity detector of the FIA manifold. The dependence of the analytical signal on the initial conductivity of the acceptor streams containing HNO3 is graphically presented. Calibration graphs were non-linear for water, strong acids, and barbituric acid over concentrations 0-1 vol% ammonia in N3, but they were linear for 3 mM boric acid.
Ammonia Conductometry Microporous membrane Polyvinylidene difluoride Gas diffusion

"Flow Injection Analysis Of Nitrogen Dioxide Using A Galvanic Detector"
J. Autom. Methods Manag. Chem. 1998 Volume 20, Issue 1 Pages 17-21
SHAN-JUN LIU, HAN-XI SHEN, JIAN-XING FENG, and M. TUBINO

Abstract: A flow injection configuration (FIA) uses a galvanic detector for the determination of NO2. The gaseous sample is directly injected into a gas carrier. The sample transported toward the detector. The steady state measurements are not required to obtain reproducible peak signals. The features of FIA are compared with that of continuous-flow monitoring application. The flow injection system is simple, rapid and capable of detecting NO2 in the range 1-500 ppm(v/v). The measuring range and sensitivity of the galvanic detector in FIA depend on the sample volume The relative standard deviation is 2.4% (n = 10) for 200 ppm (v/v) of NO2. The sampling frequency is ~24/h.
Nitrogen dioxide Galvanometry Gas phase detection Method comparison

"New Flow Injection Analyser For Monitoring Trace Hydrogen Cyanide In Process Gas Streams"
Process Control Qual. 1994 Volume 5, Issue 4 Pages 259-265
D.C. Olson, S.R. Bysouth, P.K. Dasgupta and V. Kuban

Abstract: The analyzer. is shown diagramatically. The FIA manifold is a three-stream configuration. The main stream comprising a caustic solution flowed through a gas-permeation unit (GPU) which acted as the sample loop. The HCN permeated the walls of the silicane tubing and was collected into the caustic solution The HCN concentrations became enriched before being flushed from the GPU and merging with a buffered chloramine-T stream and then with a buffered reagent mixture of isonicotinic acid and 3-methyl-1-phenyl-2-pyrazalin-5-one. The intensely colored purple product formed was measured at 630 nm in an optical cell. A pH cell downstream from the detector was used for pH monitoring as the system is pH sensitive with an optimum response in the pH range from 6.5-7.3. The flow rates are given. The system was capable of measuring from low ppb to high ppm levels of HCN in gas streams in the presence of at least 5000 ppm of H2S. The method may be used for other gases such as H2S, CO2, SO2 and NH3.
Hydrogen cyanide Spectrophotometry Gas diffusion Optimization Process monitoring Silicone tubing

"Applications Of A Mercury-vapor Atomic-fluorescence Detector"
Spectroscopy 1991 Volume 6, Issue 7 Pages 39-41
Stockwell, P.B.;Grillo, A.C.

Abstract: The applications of an automatic Hg detector based on atomic fluorescence principles are described. The instrument can be used to detect Hg in aqueous media over a wide linear-dynamic range and was successfully applied to the determination of total, inorganic and organic Hg in aqueous environmental samples using automatic continuous-flow and flow injection modes (brief details and schematic diagrams given). In combination with a trapping system based upon adsorption - desorption of Hg on to Au-impregnated sand, the detector was also used to determine the Hg concentration. in air or gaseous samples for application in the analyzes of urban stack emissions and natural gas feedstocks on a static or continuous basis.
Mercury(II) Ethylmercury Methylmercury ion Phenylmercury Mercury Fluorescence Automation