Spraying Procedures

The spraying procedure is that used in industrial preparation of ready coated plates and sheets on a conveyor band. 

Automatic coating device. On the left, the magazine with glass plates and beneath it the conveyor belt and motor drive. To the right, the aligning tray and layer-thickness adjuster. The slurry is fed into the funnel in which it is stirred. [661] 

Takitani and Matsuda [706] have developed a transport system driven by an electric motor in order to draw the Stahl spreader regularly across the line of plates (100 cm in 30—40 sec). The device described by Mabcucci and Mitssini [429] is likewise equipped with an electric motor and the plates are drawn through beneath the trough for spreading. 

There are two types of coihniercial motor-driven apparatus at present. In one, the spreader trough is carried over the row of plates by a motor drive (Firms 15, 35) in the other, the trough is fixed and the plates are passed beneath it using motor-driven rubber rollers (Firms 33, 54). A further development of the Stahl automatic apparatus permits the rational preparation of gradient layers [675] (Firm 44). This apparatus will have automatic devices for delivery, removal and stacking of plates so that they can be dried. 

Such an apparatus is most time-saving when more than 100 TLC-plates are required daily. The experience gained in the film industry will have to be turned to account for mass preparation of TLC-plates or sheets, and preference given to a combination of conveyor belt and spraying procedure. 

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The use of fiuorescamine for the analysis of primary amines has been discussed for amino acids and biogenic amines. The reaction of this compound with amphetamine analogues is similar. The spray procedure is identical to that described for primary amino acids (Section 4.2.1.1.3). The limit of detection is 100 ng for amphetamine [84]. 

Besides the shorter curing time, the spraying procedure also plays a role in determining tensile strength. The relatively high viscosity of the adhesive caused some problems that can, however, easily be overcome in a technical process. 

Van Dijk [14 ] developed a spray procedure for coating the wire in an attempt to improve the sensitivity of the detector. The column eluent passed directly to an atomizer, the nozzle of which was situated directly above the wire and 1-2 mm above it. The effect of the spray was firstly, to concentrate the solute in the mobile phase by partial evaporation during atomization and secondly, to increase the load on... 

Figure 17. Recommended spraying procedures for applying soybean oil to reduce dust in grain. Oii may be sprayed on top of grain on conveyor (A) and/or on the underside of a cascade (B). The spray pattern (C) shouid be broad enough to cover the grain but not the sides of the conveyor. Courtesy of American Soybean Association, St. Louis, Missouri.

The concentrations of impregnating solutions vary depending on the purpose. Immersion or dipping is carried out most often with 0.5-20% solutions of silver nitrate, while 10-40% solutions of silver nitrate are recommended for the spraying procedure. 

Hartmann, P., Jager, C., Barth, S., Vogel, ]., and Meyer, K. (2001) Solid state NMR, X-ray diffraction, and infrared characterization of local structure in heat-treated oxyhydroxyapatite microcrystals an analogy of the thermal deposition of hydroxyapatite during plasma-spray procedure. J. Solid State Chem., 160, 460-468. 

Another technique to produce large-area sensors was presented by Castro et al. [72] who used a layer by layer spraying procedure starting from PCL-CNT dispersions on a substrate. The chemo-electrical properties of these sensors exposed to different vapors and vapor concentrations were analyzed (Figure 5.31) and the material s sensitivity (response amplitude Ag) was found to increase when using PCL grafted CNTs in the composites. 

Suspensions of fine-grain adsorbents can be evenly spread on carriers using commercial sprayers. The uniformity of the layer depends however on the skill of the operator when the spraying apparatus is hand operated-more so than in the other procedures. Sutter s proposed TLC with the spraying procedure [303] utilises a spray pistol in which the suspension is prepared in a container using an air current a spray chamber, like a fume cupboard, containing a grating and a spirit level and a compressor to develop the necessary pressure of 1 — 1.5 atmosphere (Firm 73). 

The purpose of this experiment is to show the efficacy of different general detection procedures for lipids. The experiment first examines spraying procedures and then considers predipping versus postdipping techniques. 

PMA versus H2SO4 spraying procedure. These two techniques are destructive. Cut the sheet in half along the vertical line with either a scissors or a razor blade. Spray one half with 50% aqueous H2SO4 and the other half with 5% ethanolic PMA (see Experiment 1). Heat these sheets in an oven as described in Experiment 1, Section 7. Compare the detection of spots using the H2SO4 spray technique versus the PMA spray technique. 

Neither iodine nor 2, 7 -dichlorofluorescein is as sensitive as the PMA and H2SO4 spray procedures. Material not detected with these two nondestructive reagents will be detected using the destructive procedures. The sensitivity of lipid detec-... 

Van Oijk (16) developed a spray procedure for coating the wire in an attempt to improve the sensitivity of the detector. The column effluent passed directly to an atomizer, the nozzle of... 

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