Silica-coated quartz rods

Another alternative solution to circumvent the detection and quantitation problems of classical TLC involves the use of silica-coated quartz rods, so-called chromarods. This has been pro-... 

Alumina (Chromarods A) was as good as silica gel (Chromarods S 111) for the separation of neutral lipids, but silica gel produced better separation and higher FID response for polar lipids Chromarods S-III (silica gel-coated quartz rods) were used to quantify neutral and polar lipids in cooked beef Nile red solution used for detection of lipids densitometry by reflectance fluorometry detection limit of assay was 25-100 ng for each lipid... 

For the quantitation of chromatograms, the development condition found by the conventional TLC was transferred to another TLC system which uses a thin quartz rod coated with silica gel of 75 p thickness and may be called thin-layer-FID chromatography . The TLC system is equipped with a flame ionization detector (FID) and commercially available as a complete set (Iatron thinchrograph model TFG-10, Iatron Co., Ltd., Tokyo). The principle of sample scanning and device for FID are almost the same as those worked out by Padley57), Szakasits et al, and... 

The Chromarod consists of a straight quartz rod coated with an adsorbing material, usually silica gel, which can be briefly exposed to a hydrogen flame. The sensitivity of the analysis depends primarily upon the proportions of ionizable carbon atoms in the compound being examined. The system is rapid, sensitive, and simple for the analysis of lipid classes. 

The combination of TLC and flame ionization detector (FID) has been successfully brought together in the form of the latroscan THIO TLC/FID instrument. Chromatographic separations are carried out on quartz rods coated with a thin layer of sintered 5-pm silica gel (the Chromarod) as the stationary phase. The chromarods are then passed through the FID to detect and quantify the separated compounds. For the sample application, a homemade device, based on a Linomat spray assembly, applies a sample as a controlled (4-15 pL/min), nebulized spray on a rotating chromarod. Sample volume can be selected from 1 to 500... 

Polar lipids separated by TLC are commonly quantified by densitometry or the lipids may be scraped off and quantified by colorimetry or gas chromatography after derivatization. The latroscan TLC-flame ionization detector system is well suited to the quantification of polar lipids. In this procedure, TLC is performed on quartz rods coated with silica. The rods are then passed through a flame ionization detector to quantify each lipid band in turn. 

The latroscan Lipid Analyzer consists of two instrumental units, the quartz silica-coated rods, or Chromarods, which constitute the TLC component. 

Planar chromatography is usually performed on a quartz rod (Chromarod ) coated with a thin layer of silica or alumina onto which the sample is developed and separated. 

A novel detection method for TLC involves use of a flame ionization detector (FID) in conjunction with quartz rods coated with a thin layer of sintered silica... 

A variation of this technique involves the use of quartz tubes coated on the inner surface with silica gel or silica gel -f CuO instead of adsorbent-coated glass rods. In the tubular TLC (TTLC) method, fractionation on the chromatotubes is carried out as in conventional TLC, followed by drying of solvent by... 

Quantitative TLC is the subject of Chapter 10 of Ref. I. The theory and techniques of densitometric TLC are elaborated in Chapter 10 of this Handbook, and general considerations and instrumental aspects of densitometric chromatogram evaluation are presented in Chapter 5. Quantification of 1 ipids and other types of compounds on quartz rods coated with an immobilized layer of silica gel or other sorbent with direct interfacing to a flame ionization detector (the Chromarod system) was reviewed by Shantha (188) and Ackman et al. (189) and is described in Chapter 13. 

Silver vessels behave quite differently from either uncoated quartz or Pyrex, or salt coated vessels. Here the slow reaction is almost completely suppressed [41]. Added gases have little influence, and the introduction of a silica rod into the vessel fails to initiate any observable chain reaction. The explosion limits are also displaced to higher temperatures. 

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