Micro Gas Chromatography

Microfluidic devices, 26 959 effect of scale on, 26 960t fabrication of, 26 963-966 Microfluidics, 26 959-980 applications of, 26 966-975 basic features of, 26 959-966 future directions for, 26 976-977 history of, 26 959 industrial impact of, 26 976 Microfluidic structures fabrication of, 26 963-966 MicroFluidic Systems, 26 976 Micro-gas chromatography (micro-GC), 6 434 37 Microgel particles... 

In each run, one channel was loaded with graphite or quartz and used as bypass reference, and one channel was loaded with reference catalyst (commercial or proprietary) for comparison. The temperature was varied from 100 to 250 °C, with a 5 min isotherm every 20 °C. Reaction products were monitored by fast gas chromatography (micro-GC) and on-line mass spectrometry (MS). The carbon mass-balance was calculated by monitoring the effluents from the bypass reactor and kept between 98 and 102%. 

Naji, O.P., Bessoth, F.G., Manz, A., Novel injection methods for miniaturised gas chromatography. Micro Total Analysis Systems, Proceedings 5th pTAS Symposium, Monterey, CA, Oct. 21-25, 2001, 655-657. 

Another extraction technique for volatile oil by online coupled packed capillary high-performance liquid chromatographycapillary gas chromatography (micro-HPLC-... 

Workshop on Bio-Analytical Applications of Gas Chromatography, Micro-Tek Instruments, Inc., Baton Rouge, La., April-May 1964... 

Rodriguez-Pereiro 1, Wasik A, Lobinski R. Trace environmental speciation analysis for organometallic compounds by isothermal multicapillary gas chromatography micro-wave induced plasma atomic emission spectrometry (MC GC MIP AES) 1977. Chem Anal 1997 (42) 799-808. 

The deterrnination of hydrogen content of an organic compound consists of complete combustion of a known quantity of the material to produce water and carbon dioxide, and deterrnination of the amount of water. The amount of hydrogen present in the initial material is calculated from the amount of water produced. This technique can be performed on macro (0.1—0.2 g), micro (2—10 mg), or submicro (0.02—0.2 mg) scale. Micro deterrninations are the most common. There are many variations of the method of combustion and deterrnination of water (221,222). The oldest and probably most reUable technique for water deterrnination is a gravimetric one where the water is absorbed onto a desiccant, such as magnesium perchlorate. In the macro technique, which is the most accurate, hydrogen content of a compound can be routinely deterrnined to within 0.02%. Instmmental methods, such as gas chromatography (qv) (223) and mass spectrometry (qv) (224), can also be used to determine water of combustion. 

Methods for iodine deterrnination in foods using colorimetry (95,96), ion-selective electrodes (94,97), micro acid digestion methods (98), and gas chromatography (99) suffer some limitations such as potential interferences, possibHity of contamination, and loss during analysis. More recendy neutron activation analysis, which is probably the most sensitive analytical technique for determining iodine, has also been used (100—102). 

Gas chromatography (gc) is inferior to hplc in separating abiUty. With gc, it is better to use capillary columns and the appHcation is then limited to analysis (67). Resolution by thin layer chromatography or dc is similar to Ic, and chiral stationary phases developed for Ic can be used. However, tic has not been studied as extensively as Ic and gc. Chiral plates for analysis and preparation of micro quantities have been developed (68). 

Concrete applications of micro reactors for chemical analysis, albeit so far not a core application, have been described [5]. Among other uses in chemical analysis, micro devices for gas chromatography, infrared spectroscopy, and photoacoustic detection are mentioned. 

The development of new fiber coatings in the near future should further improve the specificity of SPME and overcome some of the observed matrix effects. Quantification by stable isotope dilution gas chromatography/mass spectrometry (GC/MS) may assist in improving analytical performance. Along with the possible application of micro LC and capillary LC columns to in-tube SPME, the development of novel derivatization methods and the potential for the analysis of fumigant pesticides, SPME appears to be a technique with a future in the analysis of pesticide residues in food. 

Verzele, M. and Dewaele, C., Liquid chromatography in packed fused silica capillaries or micro-LC a repeat of the capillary gas chromatography story , J. HRC CC, 10, 280, 1987. 

The spectrum of new analytical techniques includes superior separation techniques and sophisticated detection methods. Most of the novel instruments are hyphenated, where the separation and detection elements are combined, allowing efficient use of materials sometimes available only in minute quantities. The hyphenated techniques also significantly increase the information content of the analysis. Recent developments in separation sciences are directed towards micro-analytical techniques, including capillary gas chromatography, microbore high performance liquid chromatography, and capillary electrophoresis. 

Key drivers for innovation in process GC are now leading to the development of micro gas chromatography... 

Liquid and gaseous products are analyzed by gas chromatography with respectively a Varian 3900 GC and a Varian 4900 micro GC. The identification of the liquid decomposition products is carried out by mass spectrometry on a GC/MS system (Shimadzu GC14A coupled with a Nermag/Quad service R10-10 C/U). 

F. De Angelis, A. Di Tullio, G. Mellerio, R. Quaresima, R. Volpe, Investigation by solid phase micro extraction and gas chromatography/mass spectrometry of organic films on stone monu ments, Rapid Commun. Mass Spectrom., 13, 895 900 (1999). 

S. Hamm, E. Lesellier, J. Bleton, A. Tchapla, Optimization of headspace solid phase micro extraction for gas chromatography/mass spectrometry analysis of widely different volatility and polarity terpenoids in olibanum, J. Chromatogr. A, 1018, 73 83 (2003). 

Microfluidics evolved from micro-analytical methods in capillary format such as capillary electrophoresis, high-performance liquid chromatography, and gas chromatography, and has successfully revolutionized chemical and biochemical... 

Xu XR, Gu J-D (2004) Elucidation of methyl ferf-butyl ether degradation with Fe2+/H202 by purge-and-trap gas chromatography-mass spectrometry. Micro-chemJ 77 71-77... 

C30 oil, homopolymer of 1-decene, Ethyl Corp., Inc.) served as the start-up solvent for the experiments. The catalyst (ca. 5-8 g) was added to start-up solvent (ca. 300 g) in the CSTR. The reactor temperature was then raised to 270°C at a rate of l°C/min. The catalyst was activated using CO at a space velocity of 3.0 sl/h/g Fe at 270°C and 175 psig for 24 h. FTS was then started by adding synthesis gas mixture (H2 CO ratio of 0.7) to the reactor at a space velocity of either 3.1 or 5.0 sl/h/g Fe. The conversions of CO and H2 were obtained by gas chromatography (GC) analysis (HP Quad Series Micro-GC equipped with thermal conductivity detectors) of the product gas mixture. The reaction products were collected in three traps maintained at different temperatures—a hot trap (200°C), a warm trap (100°C), and a cold trap (0°C). The products were separated into different fractions (rewax, wax, oil, and aqueous) for quantification by GC analysis. However, the oil and the wax (liquid at room temperature) fractions were mixed prior to GC analysis. 

Complex matrixes typically cannot be analysed directly to obtain the selectivity and sensitivity required for most trace analysis applications. To circumvent this problem, solid-phase micro extraction techniques were used to preconcentrate analytes selectively prior to gas chromatography/ion trap mass spectrometry analysis. 

Reidy, S. Lambertus, G. Reece, J. Sacks, R., High performance, static coated silicon micro fabricated columns for gas chromatography, Anal. Chem. 2006, 78, 2623 2630... 

Microsyringe injection, gas chromatography, 4 611 Microtex polyester fibers, 13 393 Microthermal analysis, recent developments in, 79 577 Micro total analysis system (pTAS),... 

Equipment. All melting points were determined with a Mel-Temp apparatus from Laboratory Devices and are uncorrected. Gas chromatography was carried out on either a Varian Aerograph 700 or Hewlett-Packard 5880 chromatograph. Beckman IR-9 and Perkin Elmer FT-1800 spectrophotometers were used for the determination of mid-IR spectra. All NMR spectra were obtained using an IBM NR-80 FT spectrometer. Elemental analyses were determined for all new monomers and polymers by Micro-Tech Laboratories, Inc. of Skokie,... 

Yonamine M, TawU N, Moreau RL, Silva OA. 2003. Solid-phase micro-extraction-gas chromatography-mass spectrometry and headspace-gas chromatography of tetrahydrocannabinol, amphetamine, methamphetamine, cocaine and ethanol in saliva samples. J Chromatogr B Anal Technol Biomed Life Sci 789 73. 

Moser and Brukl described a method for the gravimetric determination of phosphine. Dumas used gas chromatography for the micro-determination of phosphine in the air (0.005-0.5 mg/litre), see also An automatic gas analyser, for the determination of phosphine and other substances in gases, works on the principle of the light absorption in reflection through a paper band, on which the gas causes a colour reaction with suitable reagents... 

Toluene disproportionation was carried out in a high-pressure continuous flow micro reactor. Granular catalyst (32-64 mesh, 2.5 cm ) was loaded into a stainless steel tube reactor. Toluene was fed at a rate of 10 cm h (liquid) in the flow of H2S(0.2vol.%)/H2 mixture gas (200 cm min b at 623K and 6MPa. The effluent was analyzed by gas chromatography (Shimadzu, GC-9A) by a flame ionization detector (FID). 

Adahchour, M., Wiewel, J., Verdel, R., Vreuls, R.J.J., Brinkman, U.A.T. (2005) Improved determination of flavour compounds in butter by solid-phase (micro) extraction and comprehensive two-dimensional gas chromatography. J. Chromatogr. A 1086 99-106. 

---