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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      131 060
      High dynamic range in videodensitometry—a comparative study to classic videoscanning on Gentiana extracts
      S. GADOWSKI, Karolina TOMICZAK, L. KOMSTA* (*Department of Medicinal Chemistry, Faculty of Pharmacy, Medical University of Lublin, Jaczewskiego 4, 20‑090 Lublin, Poland, lukasz.komsta@umlub.pl)

      J. Planar Chromatogr. 36, 3-8 (2023). HPTLC of Gentiana extract on silica gel with ethyl acetate - methanol - water 4:1:1. High Dynamic Range (HDR) photography was performed by combining nine Low Dynamic Range exposures (the whole camera range in 1-EV steps). Principal component analysis was applied on the classic exposures and HDR image, proving that HDR image contained the highest amount of extracted information from the TLC plate.

      Classification: 3g
      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
      130 043
      Development of the first universal mixture for use in system suitability tests for High-Performance Thin Layer Chromatography
      T.K. Tiên DO*, M. SCHMID, M. PHANSE, A. CHAREGAONKAR, H. SPRECHER, M. OBKIRCHER, E. REICH (*CAMAG, Muttenz, Switzerland; tien.do@camag.com)

      J Chromatogr A 1638, 461830 (2021). The purpose was to find the first universal HPTLC mixture (UHM), a mixture of reference compounds that could be used for the system suitability test (SST) for the full RF range in all HPTLC experiments.
      (Part 1) UHM composition: First, 56 organic molecules, detectable without derivatization, were tested on HPTLC silica gel with 20 different mobile phases (MP) belonging to different Snyder’s selectivity groups and with several polarity indices. Visualization under UV 254 nm and 366 nm. Densitometry scanning at 254 nm in absorption mode, and at 366 nm in a fluorescence mode (mercury lamp 366 nm, with wavelength filter <400 nm). For selected bands, spectra were recorded in absorbance-reflectance mode (wavelength range 190 – 450 nm, deuterium and tungsten lamp). This procedure allowed 8 molecules to be selected for their better spot resolution and for their specific RF values (at least 3 different values distributed throughout the full RF range for each MP). The final composition of UHM was: thioxanthen-9-one (0.001 %), guanosine (0.05 %), phthalimide (0.2 %), 9-hydroxyfluorene, octrizole, paracetamol, sulisobenzone and thymidine (each 0.1 %), in methanol.
      (Part 2) UHM validation: Afterwards, UHM was submitted again to a panel of HPTLC assays with always two MP: (A) toluene – methanol – diethylamine 8:1:1; (B) ethyl acetate – formic acid – water 15:1:1; and for each MP, the means, standard deviation and 95 % confidence intervals of the RF values were calculated. (a) UHM was validated for intermediate intra-laboratory precision, as well as for inter-laboratory reproducibility, with ΔRF 0.045. (b) The capacity of UHM to detect small variations was demonstrated by significant changes in at least some RF values, when separation was deliberately performed at different levels of relative humidity (0 %, 33 %, 75 %, 100 %), or with smaller humidity variations (7 % compared to 0–5 %, and 49 % compared to 33 %), or when performing vs. omitting the 10min chamber pre-saturation, or when modifying the MP (+/-10% of one solvent at each time). These response characteristics (the opposite of robustness) made UHM a powerful tool for SST. (c) Finally, UHM stability was studied with UHM aliquots under several storage conditions (-78 °C, -20 °C, 4 °C, room temperature, 45 °C; or 40 °C with 75 % relative humidity) and durations (2 weeks or 2 months). The densitometric peak profiles at 254 nm were compared to those of the fresh compounds, qualitatively (RF value, UV spectrum) and quantitatively (peak area). UHM was stable at room temperature or below, for 2 months (at higher temperature, guanosine, phthalimide and paracetamol degraded).

      Classification: 2f, 3g, 7, 21a, 23e, 24
      130 108
      A pattern recognition method on smartphones for planar chromatography and verification on chromatograms of four herbal medicines from citrus fruits
      T. TANG (Tang Tie xin)*, H. LIU (Liu Hui), L. DENG (Deng Lihe), X. QIU (Qiu Xinhua), J. LIANG (Liang Jiefei) (*Department of Pharmacy, Zhaoqing Medical College, Zhaoqing, China, tangtiexin@zqmc.edu.cn)

      J. Liq. Chromatogr. Relat. Technol. 44, 484-489 (2021). HPTLC of caffeic acid (1), rutin (2), naringin (3), and hesperidin (4) in samples of citrus fruits on polyamide plates with a microemulsion - formic acid 47:1. Microemulsion was prepared as follows: 2.7 g of SDS in 90 mL water, followed by adding 6.3 mL n-butanol and 1.0 mL n-heptane, and the mixture was shaken to produce a uniform and transparent O/W microemulsion. Detection by spraying with 1 % aluminum trichloride aqueous solution and photographed using a smartphone under UV light at 365 nm. Image retrieval techniques combined with support vector machine (SVM) directly classified the chromatograms based on migration path images.

      Classification: 3g
      128 011
      Open-source add-on kit for automation of zone elution in planar chromatography
      T. HÄBE, Gertrud MORLOCK* (*Justus Liebig University Giessen, Heinrich-Buff-Ring 26–32, 35392 Giessen, Germany, gertrud.morlock@uni-giessen.de)

      Rapid Commun. Mass Spectrom. 34, 8631 (2020). A 3D-printed, fully automated, open-source add-on user interface was built for elution-head-based TLC/HPTLC-MS. The system allowed a very compact plate-positioning system combined with an image-based software solution providing a platform to control and synchronize all steps from positioning, elution, advanced cleaning to MS data acquisition.

      Classification: 3g
      125 037
      Comprehensive HPTLC fingerprinting: A novel economic approach to evaluating the quality of Ganoderma lucidum fruiting body
      Débora FROMMENWILER*, D. TREFZER, M. SCHMID, S. CAÑIGUERAL, E. REICH (*Unit of Pharmacology, Pharmacognosy and Therapeutics, Faculty of Pharmacy and Food Sciences, University of Barcelona, Av. Joan XXIII, 27-3, ES-08028 Barcelona, Spain, debora.frommenwiler@camag.com)

      J. Liq. Chromatogr. Relat. Technol. 43, 414-423 (2020). HPTLC fingerprint of Ganoderma lucidum fruiting body on silica gel with toluene - tetrahydrofuran - acetic acid 70:30:1. Detection by dipping into a solution of 10% sulfuric acid in methanol, followed by heating at 100 ºC for 3 min. Qualitative determination under UV light at 254 and 366 nm. The hRF values for ganoderic acids D, B, A, G and C2 were in the zone between 10 and 50. This zone was used for quantification of total triterpene acids by absorbance measurement at 260 nm. Linearity of each of the main peaks between hRF 10 to 50 was determined. The linear range of ganoderic acid A was between 200 and 500 ng/zone.  The study proposes a new method for evaluation, based on “comprehensive high-performance thin layer chromatography (HPTLC) fingerprinting.” Instead of several different methods using different chromatographic techniques, a single HPTLC analysis for identification of Ganoderma lucidum fruiting body with a test for adulteration and quantitative determination of the content of total triterpene acids is proposed. As an alternative to the current tests in the  USP monograph on G. lucidum fruiting body this HPTLC method is a single, low-cost test, which eliminates the UHPLC assay of total triterpene acids.

      Classification: 3g, 14
      56 028
      Coumarins from polygala paniculata
      M. HAMBURGER, M. UPTA, K. HOSTETTMANN

      Planta med. 1985, 215-217.: TLC of various coumarins on silica with toluene - ethyl acetate 6:4 or dichloromethane - methanol 95:5. Detection by UV 366 nm. Preparative separation by centrifugal TLC on silica (layer thickness 2mm) with petrol ether - chloroform 1:9.

      Keywords: herbal
      Classification: 3g, 8b
      77 034
      Imaging of thin-layer chromatograms using matrix-assisted laser desorption/ionization mass spectrometry
      A.I. GUSEV, O.J. VASSEUR, A. PROCTOR, A.G. SHARKEY, D.M. HERCULES, (Dept. of Chem., Univ. of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA)

      Anal. Chem. 67, 4565-4570 (1995). Introduction of a new approach for direct coupling TLC with matrix-assisted laser desorption/ionization mass spectrometry. To avoid excessive analyte spreading along a TLC plate, a matrix layer was first generated on a different substrate, from which it was transferred to the plate. The transfer was accomplished by pressing the matrix onto a previously wetted TLC plate. Successful direct imaging of silica gel TLC plates with high spatial resolution (250-500 µm) and high sensitivity has been demonstrated for several compounds, including rhodamine B, guinea green B, bradykinin, and angiotensin II, in the nanogram range. The detection limit was in the picogram range.

      Keywords:
      Classification: 3g, 4e