High-performance, thin-layer chromatography

As in other chromatographic techniques overall performance in TLC is inextricably linked to the physical characteristics of the sorbent, in particular its particle and pore size and the particle size distribution. Normal TLC plates, i.e. those spread with 5 40 pm particle size distribution are capable of giving 1000-2000 theoretical plates per 5 cm migration. High performance 

However, due to the greater resistance to capillary flow eluant runs are only of the order of 8 cm and hence to capitalise on the benefits of HPTLC it is necessary to apply analytes to the plates in as small a spot diameter as possible. There are a range of semi automatic and automatic sample applicators available which use the technique of contact spotting which allows as much as 1000 pi of analyte solution to be applied with a spot diameter of 0.1 -0.5 mm. Pre-adsorbent layers as discussed earlier have also been used to advantage. 

The full range of development procedures have been exploited with HPTLC and detection, whether by colour development, quenching of in situ fluorescent agents or by scanning densitometry techniques can be undertaken as for conventional layers. 

In addition to the established reversed phase layers a wide range of chemically modified silica layers have been developed for HPTLC in many ways paralleling the developments in HPLC. Plates with amino and nitrile modification are available with and without fluorescent indicator microcrystalline cellulose with a mean degree of polymerisation between 40 and 200 is also available in ready to use sheets. 

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Commercially available pre-coated plates with a variety of adsorbents are generally very good for quantitative work because they are of a standard quality. Plates of a standardised silica gel 60 (as medium porosity silica gel with a mean porosity of 6mm) released by Merck have a specific surface of 500 m /g and a specific pore volume of 0.75 mL/g. They are so efficient that they have been called high performance thin layer chromatography (HPTLC) plates (Ropphahn and Halpap J Chromatogr 112 81 1975). In another variant of thin layer chromatography the... 

Hezel, U. B., in Zlatkis, A., Kaiser, R. E. HPTLC - High Performance Thin Layer Chromatography. J. Chromatogr. Library, Vol. 9. Elsevier, Amsterdam 1977. 

HIGH PERFORMANCE THIN-LAYER CHROMATOGRAPHY (HPTLC)... 

Recent developments in the practice of thin-layer chromatography have resulted in a breakthrough in performance which has led to the expression high performance thin-layer chromatography . These developments have not been the result of any specific advance in instrumentation (as with HPLC), but rather the culmination of improvements in the various operations involved in TLC. The three chief features of HPTLC are summarised below, but for a comprehensive account of the subject the reader is recommended to consult a more specialised text.59... 

High performance thin-layer chromatography has found its greatest application in the areas of clinical (e.g. analysis of drugs in blood) and environmental analysis. 

A Zlatkis and R E Kaiser (Eds), HPTLC High Performance Thin-Layer Chromatography, Elsevier, Amsterdam, 1977... 

HPTLC, high performance thin layer chromatography. 

The reason for this lies not least in the increasing instrumentalization and delibei automation of all those processes which were earlier particularly subject to eri (Fig. 2). Modem high performance thin-layer chromatography (HPTLC) is no Ion inferior to other liquid chromatographic techniques with respect to precision and s sitivity (Fig. 3) [6]. 

Gupta, A.P., Gupta, M.M., Kumar, S., Simultaneous determination of curcuminoids in curcuma samples using high performance thin layer chromatography, J. Liq. Chromatogr. Rel. TechnoL, 22, 1561, 1999. 

Morita et al. [69] optimized the mobile phase composition using the PRISMA model for rapid and economic determination of synthetic red pigments in cosmetics and medicines. The PRISMA model has been effective in combination with a super modihed simplex method for fadhtating optimization of the mobile phase in high performance thin layer chromatography (HPTLC). 

FIGURE 6.19 Circular chromatography of dyes on precoated silica gel high-performance TLC plate lipophilic dyes, mobile phase hexane-chloroform-NH3, 70 30. (From Ripphahn, J. and Halpaap, H., HPTLC High Performance Thin Layer Chromatography, Zlatkis, A. and Kaiser, R. E., Eds., Elsevier, Amsterdam, 1977, pp. 189-221. With permission.)... 

Principles and Characteristics High-performance thin-layer chromatography (HPTLC), also known as planar chromatography, is an analytical technique with separation power and reproducibility superior to conventional TLC, which was first used in 1938 [7] and modified in 1958 [8]. HPTLC is based on the use of precoated TLC plates with small particle sizes (3-5 xm) and precise instruments for each step of the chromatographic process. 

HPTLC High-performance thin-layer chromatography-mass spectrometry... 

Hydride Generation Atomic Absorption Spectrometry High Performance Liquid Chromatography High Performance Thin-Layer Chromatography High Resolution... 

Sequaris J.M.L., Koglin E., Direct analysis of high-performance thin-layer chromatography spots of nucleic purine derivatives by surface-enhanced raman-scattering spectrometry, Anal. Chem. 1987 59 525-527. 

HPTLC high-performance thin layer chromatography MEPP miniature end-plate potential... 

High-performance thin-layer chromatography (HPTLC) has become widely used and while it follows the same principles as TLC, it makes use of modern technology including automatic application devices and smaller plates, which allow for better sensitivity. 

S.J. Costanzo, High performance thin-layer chromatography, J.Chem. Educ., 61 (1984) 1015-1018. 

D.C. Fenimore and C.M. Davis, High performance thin-layer chromatography, Anal. Chem., 53 (1981) 252A-266A. 

A.M. Siouffi, From thin-layer chromatography to high performance thin-layer chromatography to planar chromatography, in H. J. Issaq (Ed.), A Century of Separation Science, Marcel Dekker, Inc., New York, 2002, pp. 69-85. 

J.H.Y. Vilegas, F.M. Lancas, J.-N. Wauters, L. Angenot, Characterization of adulteration of Espinheira Santa (Maytenus ilicifolia and Maytenus aquifolium, Celastraceae) hydroalcoholic extracts with Sorocea bomplandii (Moraceae) by high-performance thin layer chromatography. Phytochem. Anal. 9 (1998) 263-266. 

A. Jamshidi, M. Adjvadi and S.W. Husain, Determination of kaempferol and quercetin in the extract of Ginkgo biloba leaves by high-performance thin-layer chromatography (HPTLC). J. Plan. Chromatogr.—Mod. TLC. 13 (2000) 57-59. 

G. Matysik, E. Soczewinski, M. Wojciak-Kosior and E. Wojtasik, Optimization of chromatographic systems for the high-performance thin-layer chromatography of flavonoids. Chromatographia 52 (2000) 357-362. 

M. Lambri, M. Jourdes, Y. Glories and C. Saucier, High performance thin layer chromatography (HPTLC) analysis of red wine pigments. J. Planar Chromatogr.—Mod. TLC 16 (2003) 88-94. 

Weerheim A, Ponec M (2001) Determination of stratum corneum lipid profile by tape-stripping in combination with high-performance thin-layer chromatography. Arch Dermatol Res 293 191-199. 

We further used a quantitahve procedure to determine the amounts of externalized PS on the surface of apoptohc cells based on its availability to react with fluorescamine, a non-permeating reagent readily interacting with primary amino-groups. Subsequent separahon (by high performance thin-layer chromatography) and quantitahon of fluorescamine-modified PS permits determinahon of absolute amormts of externalized PS on the outer leaflet of plasma membrane. We were also able to determine the amounts of PnA-phospholipids oxidized during apoptosis based on their disappearance in the course of apoptosis. Thus both PS oxidahon and extemalizahon could be assessed. 

Muscarine is detected by high-performance thin-layer chromatography (HPTLC), with a limit of detection of 50 ng (Stijve, 1981). Using Dragendorff reagent, muscarine appears as an orange spot. 

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