Scanners, thin layer chromatography

The ultraviolet reflectance absorbance spectrum of a benzoic acid spot on a thin-layer chromatography place was recorded on a Shimadzu CS-930 TLC scanner, and is shown in Figure 5. The spectrum was obtained on a silica-gel F254 pre-coated TLC-plate (E. Merck) after elution with 7 2 2 acetone/ammonia 25 %/isopropanol. The absorbance maximum for this system was determined to be 225 nm. 

The method of Denda et al.14 was used to measure ceramides. After SC was stripped with adhesive cellophane tape, it was removed from the tape and washed several times with hexane, followed by drying in a vacuum desiccator. Lipids were extracted from the SC sample in a mixture of chloroform and methanol (2 1). Ceramides were separated with a silica gel column (Bond Elut SI, Analytichem International, United States) and purified for measurement by gas chromatography (GC-14A, Shimazu Manufacturing Co., Ltd., Japan). The composition of ceramides was obtained by high-performance thin layer chromatography and scanned on a recording photodensitometer (TLC Scanner CS930, Shimazu, Japan). 

The CAMAG Thin Layer Chromatography Scanner Conrtesy of CAMAG Inc. 

In order to achieve the optimum accuracy, precision, and sensitivity, most quantitative analyses are performed by using high-performance thin-layer chromatography (TLC) plates and direct quantification by means of a modern optical densitometic scanner with... 

Pig. 4.25. Schematic pathway of radiation in a typical thin-layer chromatography scanner. This set-up allows the measurement in transmission, reflection and fluorescence. The optical arrangement and the light source are varied acccnding to the problem. 

The fluorometric determination of PAH is based on the advanced technique of thin-layer chromatography coupled with in situ fluorescence spectrometry using optical scanners. A detailed description of this procedure has already been published (11). 

Mustoe, S.P. McCrossen, D. A comparison between slit densitometry and video (flatbed scanner) densitometry for quantitation in thin layer chromatography. Chromatographia 2001, 53 (Part 2, Suppl. S 2001), S474— S477. 

Johnson, M.E. Rapid, simple quantitation in thin layer chromatography using a flatbed scanner. J. Chem. Educ. 2000, 77 (3), 368-372. 

A thin layer chromatography (TLC) scanner is used for the quality control of a radioactive labelled product. It firstly separates the different radiochemical forms by chromatography and subsequently measures the radiation of the spot of the intended radiopharmaceutical and the unwanted by-products (see Sect. 15.6.7 quality control). 

Rock, C. O., Jackowski, S., and Shulman, S. D. (1988). Imaging scanners for radiolabeled thin layer chromatography. BioChromatography 3 127-129. 

Smith, I. (1988). The Ambis two dimensional beta scanner. In Recent Advances in Thin Layer Chromatography, F. A. A. Dallas, H. Read, R. J. Ruane, and I. D. Wilson (Eds.). Plenum Press, New York, pp. 77-86. 

A methanol extract of the polyurethane is applied to a thin-layer chromatography plate and developed with a mixture of chloroform, ethylacetate, ethanol, glacial acetic acid (120 33 20 7 v.v). Fluran spray reagent reveals the two diaminotoluene isomers. The intensity of the spots are evaluated (500 nm excitation 340 nm emission) using a spectrofluorimeter coupled to a thin film scanner and photomultiplier microphotometer. The method is calibrated against standard solutions of the two diaminotoluene isomers. 

A thin layer chromatographic (TLC) scanner or high performance liquid chromatography (HPLCy is often described for the determination of paeoniflorin in the crude drug. But the latter is more simple, more accurate and suitable for quantitative determination of single component in compounded preparations. 

After development the radioactive bands were located using a Panax thin layer scanner and provisionally identified by co-chromatography with reference compounds. Those areas corresponding to the bands were then removed from the plate and the radioactivity eluted and estimated by scintillation counting. Results are expressed as d.p.m. per sq.mm per hour. 

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