Injector models

Injection Syringe Loading Sample Injector Model 7125 (Rheodyne, USA)... 

Pumping System SP3500 (Spectra-Physics) Injector Model U6K (Waters Associates)... 

Detector UV 254 E, ESA Coulochem Model 5100A, Model 5020 guard cell -0.8 V (placed before the injector), Model 5010 dual-electrode analytical cell with glassy-carbon electrodes (-0.8 V first electrode, -1-0.8 V second electrode)... 

Liquid Chromatography System. The solvent delivery system was constructed of two lO-mL stainless-steel syringe pumps (MPLC Micropump, Brownlee Labs, Santa Clara, CA). By splitting the pump effluent between the mlcrocolumn and a restricting capillary (1 20-1 2000), Isocratlc separations were achieved reproduclbly at column flowrates as low as 0.005 pL/mln, and gradient separations as low as 0.1 pL/mln. Samples of 0.5 to 50 nL volume were Introduced by the split Injection technique with a 1- L valve Injector (Model ECI4W1., Valeo Instruments Co., Inc., Houston,... 

Santa Clara, CA). The column had a diameter of 3.2 mm, and the exit frit was crimped into place so that a column end fitting was not required. The geometry of the electrochemical cell is shown in Figure 4. The chromatographic system included a pneumatically operated loop Injector (Model 3XL, Scientific Systems, Inc., State College, PA). The injection loop had a 10 pL volume, and mixtures of catecholamines were used as test compounds. The electrode could be positioned with 100 pm resolution in three dimensions with a micromanipulator (Narlshige Co., Ltd., Tokyo, Japan). The vertical resolution was enhanced with a piezoelectric positioner with 0.5-pm resolution (Burleigh Instruments, Inc., Fishers, NY). 

Magargle R, Hoburg JF, Mukherjee T (2006) Microfluidic injector models based on artificial neural networks. IEEE Trans Comput-Aid Design Integr Circ Syst 25(2) 373-380... 

Apparatus A sample injector model U6K, solvent delivery systems M45, a variable wavelength detector model 440 (Waters Assoc-, Milford, Mass.) and an automatic recorder Omniscribe... 

High-performance liquid chromatography (HPLC) analysis is carried out on an XL ODS Cjg, 3-fim (70 x 4.6 mm) column (Beckman Instruments Inc., Altex Division, San Ramon, CA). HPLC purification is carried out on a Nucleosil Cjg, 5- im (250 x 10 mm) column (SFCC/ Shandon, Eragny, France) with an increasing proportion of acetonitrile (5-15%) in 0.05M triethylammonium acetate, pH 7, as eluant. A Waters U6K injector. Model 510 pumps, an M 720 gradient controller, and a Waters 990 photodiode array detector are employed. 

Ethanol concentration in the fermentation broth is determined by using gas chromatography (HP 5890 series II with HP Chemstation data processing software, Hewlett-Packard, Avondale, PA) with a Poropak Q Column, and a Hewlett-Packard model 3380A integrator. A flame ionisation detector (FID) is used to determine ethanol. The oven temperature is maintained at 180 °C, and the injector and detector temperature are maintained at 240 °C. The sample taken from the fermentation media has to be filtered and any internal standard must be added for analysis based on internal standard methods otherwise, the area under the peak must be compared with known standard samples for calculation based on external standard methods. 

Gas chromatography analysis was performed on a Hewlett Packard GC Model 5890 equipped with a flame ionization detector and automatic injector 7673A. 

Ensure that the actual instrument configuration conforms to what is written under Experimental supplier, models, modifications, consumables (HPLC or GC columns, gaskets, etc.), and software for the main instrument, peripherals (injectors, integrators, computers, printers, plotters, etc.), and ancillary equipment (vortexer, dispensers, balances, centrifuges, filters, tubing, etc.). 

GC-TEA Analysis. A Bendix model 2200 GC and Thermo Electron model 502 TEA were used. The GC injector temperature was 210 C. The TEA pyrolysis furnace was operated at 450 C and the cold trap was held at -150 C in isopentane slush. Oxygen flow to the ozonator was 20 cc/min and indicated pressure was 1.5 torr at a helium flow rate of 20 cc/min. TEA output was processed by a digital integrator (Spectra Physics System I). 

Model GC6890, Hewlett-Packard Pulsed splitless sample injector. Column head pressure, 98 kPa pulse pressure, 240 kPa pulse time, 0.5 min... 

Model GC5890, Hewlett-Packard Splitless sample injector... 

Gas chromatograph [Flewlett-Packard (FIP) 5890 or 6890 GC with HP 7673 or 6890 Series injector and OI Analytical Model 5220 electrolytic conductivity detector or 5360 halogen-specific detector HP 5890 or 6890 equipped with HP 7673 or 6890 Series injector and HP 5970 or 5972 mass-selective detector]... 

Gas chromatograph. Model 3400 (Varian, San Jose, CA, USA) equipped with split/ splitless injector and a niAogen-phosphorus detector (GC/NPD) or equivalent Heater, HPLC column... 

Gas chromatograph. Model 6890 (Agilent Technology) equipped with split/splitless injector and a mass spectrometer. Model 5973, or equivalent Tissumizer, Model SDT 1810 SI with S25N probe (Tekmar, Cincinnati, OFl, USA) or equivalent... 

The extracted fractions were esterified with either BF3-MeOH reagent or diazomethane and analyzed by GLC. Gas liquid chromatography (GLC) was conducted with a Perkin-Elmer Sigma 3 equipped with flame ionization detector. Separations were obtained on a Hewlett Packard 12 m x 0.2 mm i.d. capillary column coated with methyl silicon fluid (OV-101). The temperature was maintained at 80°C for 2 min then programmed from 80 to 220°C at 8°C/min. The injector temperature was 250°C. Mass spectra were obtained on a Hewlett Packard model 5995 GC-MS mass spectrometer, equipped with a 15 m fused silica capillary column coated with 5% phenyl methyl silicone fluid. Spectra were obtained for major peaks in the sample and compared with a library of spectra of authentic compounds. 

The waxes, the organic phase, and the aqueous products, on the contrary, were unloaded daily from the collection traps and analyzed with an off-line GC (Hewlett-Packard model 6890) equipped with two flame ionization detectors and two identical columns (Hewlett-Packard HP-5), one connected to an on-column injector and dedicated to the analysis of waxes (dissolved in CS2 before the injection), and the other connected to a split/splitless injector and used for the analysis of the liquid reaction products (aqueous and organic phases). CH3CN was added to the aqueous sample prior to the injection as internal standard. 

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