Cumulative CAMAG Bibliography Service CCBS

Our CCBS database includes more than 11,000 abstracts of publications. Perform your own detailed search of TLC/HPTLC literature and find relevant information.

The Cumulative CAMAG Bibliography Service CCBS contains all abstracts of CBS issues beginning with CBS 51. The database is updated after the publication of every other CBS edition. Currently the Cumulative CAMAG Bibliography Service includes more than 11'000 abstracts of publications between 1983 and today. With the online version you can perform your own detailed TLC/HPTLC literature search:

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      130 081
      Applicability of the Universal Mixture for describing system suitability and quality of analytical data in routine normal phase High Performance Thin Layer Chromatography methods
      M. SCHMID, T.K. Tiên Do*, I. TRETTIN, E. REICH (*CAMAG, Muttenz, Switzerland; tien.do@camag.com)

      J Chromatogr A 1666, 462863 (2022). Theoretical discussion on the factors determining the RF value of a given substance in a chromatographic system: A) the stationary phase (SP); B) the mobile phase (MP), the composition of which can be different from the solvent mixture prepared because of evaporation, saturation and liquid or gas adsorption effects over migration time; C) the difference of the free energies for the analyte transfer from SP to MP; D) external parameters like temperature and humidity. The universal HPTLC mixture (UHM) is a mixture of reference compounds that can be used for the system suitability test (SST) for the full RF range in all HPTLC experiments. Its composition is: thioxanthen-9-one (0.001 %), guanosine (0.05 %), phthalimide (0.2 %), 9-hydroxyfluorene, octrizole, paracetamol, sulisobenzone and thymidine (each 0.1 %), in methanol. The purpose was to study the potential of UHM to replace SST (described with specific markers in European Pharmacopoeia monographs) and to assess the quality of HPTLC results. TLC and HPTLC silica gel on different support (aluminium, glass) or with different granulometries and binders (classic, Durasil, Adamant), of the UHM, an acetonitrile extract of Abelmoschus manihot flowers (Malvaceae), a methanol extract of Sambucus canadensis flowers (Adoxaceae), and essential oils of Lavandula angustifolia, of Mentha × piperita (Lamiaceae) and of Myristica fragrans (Myristicaceae), as well as the following specific markers (standards): borneol, bornyl acetate, linalool, linalyl acetate (terpenoids), isoeugenol, isoeugenol acetate, chlorogenic acid (phenylpropanoids), gossypin (flavone), gossypetin-glucuronide, hyperoside (flavonol heterosides). Development (after 20 min plate conditioning with a saturated MgCl2 solution) with one of the following mobile phases: (MP1) toluene – ethyl acetate 19:1, especially for essential oils; (MP2) ethyl acetate – butanone – formic acid – water 5:3:1:1, especially for S. canadensis; (MP3) ethyl acetate – acetic acid – formic acid – water 100:11:11:26, especially for A. manihot. Documentation in UV 254 nm and 350 nm, and with white light (reflection + transmission), before and after derivatization. RF values were determined by scanning densitometry at 254 nm in absorption mode (for octrizole, at 366 nm in fluorescence mode with mercury lamp and optical filter K400 nm). For each HPTLC condition, intra-laboratory precision assay of UHM separation was performed (at least 5 analyses) with average RF values and 95 % prediction intervals, and calculating RF differences between pairs of UHM constituents and 95 % confidence intervals, which were max. +/-0.012 of the RF values for all UHM and markers. The sensitivity of UHM, and thus its usefulness as generic SST was demonstrated by repeating the HPTLC experiments with modifying by 10 % the quantity of one of the solvent each time. There were always significant changes in RF values of UHM components and/or in RF differences between pairs of UHM bands; it was often but no always the case with the official specific markers. UHM underwent also significant changes (although less than A. manihot extract) when several silica gel phases were compared under the same HPTLC conditions. This property is crucial to verify the right stationary phase before doing any RF correlations, and could make UHM a universal tool to identify discrepancies between different analyses. Finally, the use of UHM for a computer-supported evaluation of HPTLC results was discussed, either for zone identification and RF corrections (within confidence intervals), or for correlations of entire fingerprints as first step to implement machine learning algorithms.

      Classification: 2a, 2f, 3g, 7, 8a, 15a, 15b, 32e
      130 023
      Quality standard of traditional Chinese medicines: comparison between European Pharmacopoeia and Chinese Pharmacopoeia and recent advances
      F. LEONG (Leong Fong), X. HUA (Hua Xue), M. WANG (Wang Mei), T. CHEN (Chen Tongkai), Y. SONG (Song Yuelin), P. TU (Tu Pengfei), X. CHEN (Chen Xiao-Jia)* (*State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macao, China; xiaojiachen@um.edu.mo)

      Chinese Medicine 15, 76 (2020). This review compared the 2020 editions of Chinese (ChP) and European Pharmacopoeas (EuP) in different aspects of quality control of traditional Chinese medicinal plants (73 of which drugs were common to both, but with differences in species or organs for 17 of them). Discussed points included history, identification, plant origin and processing, sample preparation, marker selection, tests and assays, as well as advanced analytical techniques for quality control and for the establishment of comprehensive quality standard. TLC was discussed in relation to its following aspects: purposes, markers/references, techniques and result description.
      (A) The main uses of TLC and HPTLC were (1) chemical-based identification of the plant in a more accurate and precise method than by macroscopic and microscopic observation only, and in a more direct and easily interpretation than HPLC, and allowing the simultaneous analysis of multiple samples in parallel; (2) control of possible adulterants; (3) quantification of active compounds. Both uses (1) and (2) were combined in some EuP monographs: as example were given the roots of Angelica dahurica, A. pubescens, A. sinensis, using TLC for identification of the species and of adulterants from other species (Angelica, Levisticum and Ligusticum).
      (B) In ChP, identification through TLC was in most cases achieved by fingerprint comparison to an official reference extract or herb (herbal reference substance). At the opposite, EuP often indicated analytical markers, irrespective of any pharmacological activity, but chosen only for analytical purposes in TCM identification and quantification. Examples were: aescin and arbutin as analytical markers for TLC identification of Anemarrhena asphodeloides rhizome and Panax notoginseng root.
      For the TLC system suitability assessment tests, ChP used the same intensity markers or active markers that were chosen for the identification or assay; whereas EuP often used other specific references, e.g. isoeugenol and methyleugenol in the case of Ophiopogon japonicus roots.
      (C) For the techniques, conventional separations and chemical derivatizations were used. Hyphenations of TLC to other analytical methods (e.g. MS) were absent. Only one monograph applied an effect-directed analysis directly on TLC chromatogram (free DPPH• radical scavenging assay for TLC identification of Rehmannia glutinosa root, in ChP).
      Sometimes, the TLC methods were different between both reference books for the same species. Example was given for Belamcanda chinensis (=Iris domestica) rhizome: in EuP, development on silica gel with cyclohexane – ethyl acetate – acetic acid 20:80:1, detection under UV 254 nm, comparison to standards coumarin and irisflorentin; whereas in ChP, development on polyamide layer with chloroform – butanone – methanol (3:1:1), detection under UV 365nm after derivatization with aluminium chloride, comparison to a reference rhizome powder.
       (D) Finally, the results in ChP were described as a text stating the similarity of sample profile with the profile of the chosen reference, whereas the results in EuP were described with a schematic box indicating the positions of bands of interest.

      Classification: 1, 2a, 32e
      57 013
      Chinese J
      ZH. LUO (Luo Zhiguan), L. CHENG (Cheng Ling)

      Chromatogr. 2, 287-289 (1985).(Chinese) (Application of the chord distance method to the selection of thin-layer chromatography and paper chromatography optimal combination.) Study on the cluster analysis by using weighted pair-group and shortest distance methods for TLC of 26 food dyes with 10 developing systems. Method optimization. The same study was made for paper chromatography of 14 amino acids with 5 developing system. The results showed advantages of the method.

      Keywords:
      Classification: 2a, 30
      59 014
      Ion-pair reversed-phase thin-layer chromatography of organic acids
      I.D. WILSON, (Dept. Drug Metabolism, Hoechst Pharm. Res. Lab., Walton Manor Walton, Milton Keynes, Buckinghamshire MK7 7AJ, UK)

      Reinvestigation of the effects of solvent pH on Rf values. J. Chromatogr. 354, 99-106 (1986). Ion-pair reversed-phase TLC of 4 organic acids on silica, paraffin-impregnated silica, and on C 18-bonded silica with 4 ion-pair- reagents. Investigation of the effects of solvent pH on Rf values. Discussion of some possible explanation and the potential usefulness of the phenomenon. Rf values of the compounds were unaffected by solvent pH, when tetra-n-butylammonium iodide and tetra-heptylammonium bromide were used as ion-pair reagents, but significant dependence of Rf on the solvent pH was found when cetrimide and cetyltrimethylammonium bromide were used.

      Keywords:
      Classification: 2a
      62 009
      Lipohilicity determination of some nitrostyrene derivatives on RP-2, RP-8 and RP-18 layers
      T. CSERHATI, A. KISS-TAMAS, GY. MIKITE, (Plant Protec. Inst., Hungarian Acad. Sci., Herman O. 15, H-1022 Budapest, Hungary)

      Chromatographia 25, 82-86 (1988). Determination of the lipophilicity of 33 nitrostyrene derivatives by reversed-phase TLC on three alkyl- bonded silicas with methanol. Discussion of the relationship between RM value of each compound and the concentration of the organic solvent, the retention strength and selec tivities of the three bonded phases, and the impact of the change of methanol concentration on the retention.

      Keywords:
      Classification: 2a, 16
      64 008
      Effect of eluent electrolyte on chromatographic retention of inorganic ions on Sephadex G-25 with cetone-water mixed eluents
      M.O. SHIBUKAWA, N.K. OHTA, T. KOYA, (Sch. Med. St. Marianna Univ., Kawasaki, Japan 213)

      J. Chromatogr. Sci., 26, 325-330 (1988). Investigation of the chromatographic behavior of inorganic ions on Sephadex G-25 with acetone - water mixed eluent system in TLC and CC. Emphasis on the effects of eluent electrolyte and of the solvent compositions inside and outside the gel beads. Evaluation of the partition effect on the retention mechanism for different salts. Proposal of a theoretical model interpreting the effect of the background eluent ions on the capacity factors of the analyte ions.

      Keywords:
      Classification: 2a, 33
      68 019
      Chromatographic behaviour of diastereoisomers X
      M.C. PALAMAREVA*, B.J. KURTEV, I. KAVRAKOVA, (* Dep. Chem., Univ. Sofia, 1126 Bulgaria)

      Thin-layer chromatographic retentions on silica of some (E)- and (Z)-oxazolones and related cinnamates as a function of mobile phase effects or Hammett constants. J. Chromatogr. 545, 161-175 (1991). Study of the TLC behavior of 20 diastereoisomeric 1,1-disubstituted 2-arylethenes [(Z)- and (E)-oxazolones and - cinnamates] on silica with 40 mobile phases. Correlation and discussion of the relative retentions and the retentions themselves with solvent selectivity effects of Hammett constants of the various substituents on the aryl group.

      Keywords:
      Classification: 2a, 8b
      77 008
      (Basic exercises on TLC
      A. KUNUGI, K. TABEI, (Sch. Life Sci., Tokyo Univ. Pharm. Life Sci., Hachioji, Japan 192-03)

      2. Experimental condition affecting resolution and Rf value.) (Japanese). Kagaku to Kyoiku (Jap. J. Sci. & Educ.) 43 (3), 178-181 (1995). Demonstration of the effect of the experimental conditions, such as pre-saturation, developing distance, developing solvent system, and the stationary phase, on the degree of resolution and Rf value in TLC analysis.

      Keywords:
      Classification: 2a