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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      130 004
      Identification of acetylcholinesterase inhibitors in water by combining two-dimensional thin-layer chromatography and high-resolution mass spectrometry
      Lena STÜTZ*, W. SCHULZ, R. WINZENBACHER (*Laboratory for Operation Control and Research, Zweckverband Landeswasserversorgung, Langenau, Germany; stuetz.l@lw-online.de)

      J Chromatogr A, 1624, 461239 (2020). Samples were chemical standards of acetylcholinesterase (AChE) inhibitors (azamethiphos, caffeine, donepezil, galanthamine, methiocarb-sulfoxide, paraoxon-ethyl) and of neurotoxic compounds, as well as drinking or contaminated water samples enriched through solid phase extraction. HPTLC on spherical silica gel (pre-washed twice by 20 min immersion in isopropanol, heated 20 min at 120 °C before and after pre-washing with acetonitrile). First separation (preparative TLC) with automated multiple development (16 steps). Effect-directed analysis for AChE inhibitors by immersion (speed 5 cm/s, time 1 s) into enzyme solution, incubation 5 min at 37 °C and immersion into substrate solution (indoxyl acetate 2 % in methanol); visualization under UV 366 nm. Active zones from untreated layers were eluted through the oval head of a TLC-MS interface to a second plate for a second separation with a panel of other mobile phases. Bands of interest were eluted from the second layer with water through the oval elution head of the TLC-MS interface pump, into a RP18 liquid chromatography guard column, followed by a quadrupole time-of-flight mass spectrometer. Full scan mass spectra (m/z 100–1200) were recorded in negative and positive modes using electrospray ionization (and collision-induced dissociation for MS2). Among the water contaminants, lumichrome (riboflavin photolysis product), paraxanthine and linear alkylbenzene sulfonates were identified as AChE inhibitors.

      Classification: 3d, 4d, 4e, 22, 29b, 35d, 37c
      130 005
      Multiobjective optimization of microemulsion – thin layer chromatography with image processing as analytical platform for determination of drugs in plasma using desirability functions
      Noura H. ABOU-TALEB*, D. T. EL-SHERBINY, N. M. EL-ENANY, H. I. EL-SUBBAGH (*Medicinal Chemistry Department, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt; nourahemdan@yahoo.com)

      J Chromatogr A, 1619, 460945 (2020). Samples were lamotrigin as standard, or extracted with an oil-in-water microemulsion (10 µL butyl acetate, 4 mL n-butanol, 925 mg sodium dodecyl sulphate, 8.6 mL water) either from patients’ raw plasma (for separation from blood proteins) after spiking, or from commercial tablets dissolved in methanol. TLC on silica gel with a water-in-oil microemulsion of 9 mL butyl acetate, 1 mL n-butanol, 250 mg sodium dodecyl sulphate, 250 µL water. Both optimal microemulsions were predicted using Taguchi orthogonal array and Plackett-Burman design. Evaluation in UV 254 nm, quantification from the digital picture using four image processing software programs. For lamotrigin (hRF 24), limits of quantification were 170 ng for pure drug and 10 ng for spiked plasma. Linearity (in range 20–200 ng/spot) was directly obtained for the calibration curve in spiked plasma; however, for pure drug, linearity was obtained only when using log values of the calculated densities (300–3000 ng/spot).

      Classification: 3a, 3d, 5c, 23e, 32c
      130 005
      Multiobjective optimization of microemulsion – thin layer chromatography with image processing as analytical platform for determination of drugs in plasma using desirability functions
      Noura H. ABOU-TALEB*, D. T. EL-SHERBINY, N. M. EL-ENANY, H. I. EL-SUBBAGH (*Medicinal Chemistry Department, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt; nourahemdan@yahoo.com)

      J Chromatogr A, 1619, 460945 (2020). Samples were lamotrigin as standard, or extracted with an oil-in-water microemulsion (10 µL butyl acetate, 4 mL n-butanol, 925 mg sodium dodecyl sulphate, 8.6 mL water) either from patients’ raw plasma (for separation from blood proteins) after spiking, or from commercial tablets dissolved in methanol. TLC on silica gel with a water-in-oil microemulsion of 9 mL butyl acetate, 1 mL n-butanol, 250 mg sodium dodecyl sulphate, 250 µL water. Both optimal microemulsions were predicted using Taguchi orthogonal array and Plackett-Burman design. Evaluation in UV 254 nm, quantification from the digital picture using four image processing software programs. For lamotrigin (hRF 24), limits of quantification were 170 ng for pure drug and 10 ng for spiked plasma. Linearity (in range 20–200 ng/spot) was directly obtained for the calibration curve in spiked plasma; however, for pure drug, linearity was obtained only when using log values of the calculated densities (300–3000 ng/spot).

      Classification: 3a, 3d, 5c, 23e, 32c
      129 071
      Comparison of high-performance thin-layer with overpressured layer chromatography combined with direct analysis in real time mass spectrometry and direct bioautography for tansy root
      Ágnes M. MÓRICZ*, T.T. HÄBE, P.G. OTT, G.E. MORLOCK
      (*Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, 1022 Budapest, Hungary; moricz.agnes@atk.hu)

      J Chromatogr A, 1603, 355–360 (2019). Samples were ethyl acetate root macerates of fully flowered Tanacetum vulgare (Asteraceae). HPTLC on silica gel (classical irregular particles vs. Lichrosphere with spherical particles) previously washed with methanol, dried for 5 min at room temperature, perimeter-sealed with a polymer coat, and heated for 30 min at 100 °C. Separation with toluene or with toluene – n-hexane 7:3, in classical capillary flow or in OPLC (overpressured layer chromatography). For OPLC, off-line infusion was used (closed mobile phase (MP) outlet, automatically stopping development); external pressure 50 bar, rapid MP flush 175 and 350 µL, MP flow rate 250 and 500 µL/min, 1830 and 3475 µL MP, development time 446 s and 424 s. Derivatization by immersion into vanillin – sulfuric acid reagent, followed by 5 min heating at 110 °C; or into PABA reagent (500 mg p-aminobenzoic acid, 18 mL glacial acetic acid diluted, 20 mL water, 1 mL o-phosphoric acid, 60 mL acetone), followed by 5 min heating at 140 °C. Effect-directed analysis using automated immersion: A) for free radical (DPPH•) scavengers; B) for activity against Gram-negative bacteria using Aliivibrio fischeri bioluminescence assay; C) for activity against Gram-positive bacteria with Bacillus subtilis bioassay. Four active polyynes were identified as hexadiynylidene-epoxy-dioxaspiro-decane (1), pontica epoxyde (nonene-triynyl-vinyl-oxirane) (2), tetradeca-triine-en-one (3) and trans-(hexadiynylidene)-dioxaspiro-decene (4), by hyphenating OPLC to quadrupole-orbitrap HRMS without eluent, using a DART interface (Direct Analysis in Real-Time, needle voltage 4kV, grid voltage 50 V, helium as gas, temperature 500 °C, full scan in positive ionization mode in m/z range 100-750). Polyynes (3) and (4) were coeluting in HPTLC but not in OPLC, demonstrating that (4) is not produced by oxidation during the DART-MS procedure. Separation with OPLC compared to HPTLC was performed in a shorter time and with better resolution at the same time. Layers with spherical particles gave higher resolution; zone distortions occurring in OPLC due to dissolved air in MP were prevented by previous MP sonication.

      Classification: 3b, 3d, 4e, 5a, 8b, 9, 32e
      129 071
      Comparison of high-performance thin-layer with overpressured layer chromatography combined with direct analysis in real time mass spectrometry and direct bioautography for tansy root
      Ágnes M. MÓRICZ*, T.T. HÄBE, P.G. OTT, G.E. MORLOCK
      (*Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, 1022 Budapest, Hungary; moricz.agnes@atk.hu)

      J Chromatogr A, 1603, 355–360 (2019). Samples were ethyl acetate root macerates of fully flowered Tanacetum vulgare (Asteraceae). HPTLC on silica gel (classical irregular particles vs. Lichrosphere with spherical particles) previously washed with methanol, dried for 5 min at room temperature, perimeter-sealed with a polymer coat, and heated for 30 min at 100 °C. Separation with toluene or with toluene – n-hexane 7:3, in classical capillary flow or in OPLC (overpressured layer chromatography). For OPLC, off-line infusion was used (closed mobile phase (MP) outlet, automatically stopping development); external pressure 50 bar, rapid MP flush 175 and 350 µL, MP flow rate 250 and 500 µL/min, 1830 and 3475 µL MP, development time 446 s and 424 s. Derivatization by immersion into vanillin – sulfuric acid reagent, followed by 5 min heating at 110 °C; or into PABA reagent (500 mg p-aminobenzoic acid, 18 mL glacial acetic acid diluted, 20 mL water, 1 mL o-phosphoric acid, 60 mL acetone), followed by 5 min heating at 140 °C. Effect-directed analysis using automated immersion: A) for free radical (DPPH•) scavengers; B) for activity against Gram-negative bacteria using Aliivibrio fischeri bioluminescence assay; C) for activity against Gram-positive bacteria with Bacillus subtilis bioassay. Four active polyynes were identified as hexadiynylidene-epoxy-dioxaspiro-decane (1), pontica epoxyde (nonene-triynyl-vinyl-oxirane) (2), tetradeca-triine-en-one (3) and trans-(hexadiynylidene)-dioxaspiro-decene (4), by hyphenating OPLC to quadrupole-orbitrap HRMS without eluent, using a DART interface (Direct Analysis in Real-Time, needle voltage 4kV, grid voltage 50 V, helium as gas, temperature 500 °C, full scan in positive ionization mode in m/z range 100-750). Polyynes (3) and (4) were coeluting in HPTLC but not in OPLC, demonstrating that (4) is not produced by oxidation during the DART-MS procedure. Separation with OPLC compared to HPTLC was performed in a shorter time and with better resolution at the same time. Layers with spherical particles gave higher resolution; zone distortions occurring in OPLC due to dissolved air in MP were prevented by previous MP sonication.

      Classification: 3b, 3d, 4e, 5a, 8b, 9, 32e
      129 063
      Automated piezoelectric spraying of biological and enzymatic assays for effect-directed analysis of planar chromatograms
      E. AZADNIYA, Gertrud E. MORLOCK* (*Institute of Nutritional Science, Justus Liebig University Giessen, and TransMIT Center of Effect-Directed Analysis, Giessen, Germany; gertrud.morlock@uni-giessen.de)

      J Chromatogr A, 1602, 458–466 (2019). HPTLC of caffeine, physostigmine (alkaloids) and hydroethanolic extract of Peganum harmala seeds (Nitrariaceae, Zygophyllaceae) on silica gel prewashed twice with methanol – water 3:1, followed by 1 h drying at 120 °C. Separation, after 5 min chamber saturation, with ethyl acetate – methanol – ammonia (25%) 85:11:4 (basic mobile phase) or ethyl acetate – toluene – formic acid – water 16:4:3:2 (acidic mobile phase, requiring neutralization with phosphate-citrate buffer). Derivatization with Dragendorff’s reagent and with anisaldehyde sulfuric acid. Effect-directed analysis by spraying A) with Gram-negative bioluminescent Aliivibrio fischeri suspension for antibacterial activity (caffeine was used as standard); B) with acetyl- and butyryl-cholinesterase (AChE / BChE) solutions for enzymatic inhibition. For AChE and BChE asssays, classical immersion into the enzyme solutions was also used for comparison, and inhibition densitometry for active analytes was performed by inverse scan measurement (fluorescence without optical filter) at 546 nm using a mercury lamp; activity was expressed as physostigmine equivalents. Active bands were eluted (only after basic MP) with methanol through the oval elution head of a TLC-MS interface pump, into a quadrupole-Orbitrap mass spectrometer. Full scan mass spectra (m/z 50−750) in positive ionization mode were recorded using heated electrospray ionization (HESI, spray voltage 3.5kV, capillary temperature 270°C). By comparison to literature, AChE inhibitors (also active against A. fischeri) were assigned to be harmine, harmaline and ruine (β-carboline alkaloids), and BChE inhibitors were harmol (same class) and vasicine and deoxyvasicine (quinazoline alkaloids, also called peganine and deoxypeganine). Piezoelectric spraying had the following advantages over automated immersion: (1) it covered the whole plate surface; (2) required much lower volumes of solutions; (3) applied always fresh enzyme or reagent solutions, thus avoiding gradual inactivation; (4) avoided zone distortions, shifts or tailings occurring during immersion or withdrawal of the plate, or due to the hydrophilicity of compounds.

      Classification: 3e, 4e, 22, 32e
      129 002
      Imaging high-performance thin-layer chromatography as powerful tool to visualize metabolite profiles of eight Bacillus candidates upon cultivation and growth behavior
      S. KRUSE, F. PIERRE, Gertrud E. MORLOCK* (*Institute of Nutritional Science, and Interdisciplinary Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University Giessen, Giessen, Germany; gertrud.morlock@uni-giessen.de)

      J Chromatogr A, 1640, 461929 (2021). Study of the impact of different strains, culture media and parameters (temperature, time, rotational speed, and glucide and amino-acid supply) on the metabolite profile of bacteria. Samples were cultivation broths of Bacillus subtilis, B. licheniformis, B. pumilus and B. amyloliquefaciens, as well as their respective supernatant liquid-liquid extracts (apolar solvents only or QuEChERS method with acetonitrile and MgSO4 – NaCl mixture 4:1). HPTLC on silica gel (normal phase and RP-18), either as bands (for small volumes of extracts) or as areas for supernatants and bigger volumes of extracts. Extract areas were focused with a three-step procedure (up to 20mm with acetone, and twice with methanol); unextracted supernatants were focused twice with methanol and once with tetrahydrofuran, but the application zone of the plate had to be cut before development, due to the high matrix load. Development with ethyl acetate – methanol – water at different ratios after activation of the plate surface with magnesium chloride (33% relative humidity), evaluation in white light and UV. Detection of antibacterial compounds with Aliivibrio fischeri bioassay. Derivatization with primuline (for lipophilic substances) and diphenylamine aniline sulfuric acid reagent (for saccharides). This method allowed a fast comparison: A) of the patterns of the different strains (presence /absence and intensity of detected or antibacterial bands); B) of cultivation parameters: the number of metabolites increased with time, rotational speed (oxygen level), and at 37°C (vs. 30°C), whereas a minimal medium allowed the detection of more metabolites, due to the lower matrix load; C) of the impact of the extraction parameters: choice of the solvents (QuEChERS method had no advantage here), solvent – supernatant ratio (1:3 showed richer patterns than 1:1); D) of the HPTLC parameters used (better separation and resolution with normal phase vs. RP18 layers).

      Classification: 3a, 10a, 11c, 27
      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