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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      131 077
      In-process quality control of wine by planar chromatography versus micro planar chomatography
      S. KIRCHERT, R. KAISER, Gertrud MORLOCK* (*Institute of Nutritional Science, Chair of Food Science, and Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany, gertrud.morlock@uni-giessen.de)

      J. Chromatogr. A. 1588, 137-149 (2019). HPTLC of sugars (1), amino acids (2), gluconic acid (3) and glycerol (4) in 20 wine samples on silica gel with i-propanol - n-butanol - boric acid solution (200 mg/10 mL) - acetic acid 14:6:3:1 for (1), 2-butanol - ammonia solution (25 %) - pyridine - water 19:5:17:13 for (2), methanol - water 7:3 for (3) and acetonitrile - boric acid solution (200 mg/10 mL) 4:1 for (4). Detection of (3) by heating at 190 °C for 20 min, followed by densitometric evaluation at 366 nm. Further detection by dipping into: 1) diphenylamine-aniline-phosphoric acid reagent, followed by heating at 120 °C for 10 min; 2) vanillin-sulfuric acid reagent, followed by heating at 135 °C for 20 min; 3) ninhydrin reagent, followed by heating at 110 °C for 5 min; 4) bromophenol blue, followed by heating at 110 °C for 10 min. Derivatized plates were documented in white light and under UV light at 366 nm. Quantification of (4) was performed using a deuterium/tungsten lamp at 380 nm. Micro planar chromatography was performed using a device, where the HPTLC foil was covered by a thick glass plate with a hole in the center, through which the mobile phase was supplied. Further analysis by mass spectrometry. 

       

      Classification: 4d, 6
      131 078
      Validated screening method for 81 multiclass veterinary drug residues in food via online-coupling high-throughput planar solid-phase extraction to High-Performance Liquid Chromatography−Orbitrap Tandem Mass Spectrometry
      A. MEHL, L. HUDEL, M. BÜCKER, Gertrud MORLOCK* (*Institute of Nutritional Science, Chair of Food Science, and Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany, gertrud.morlock@uni-giessen.de)

      J. Agric. Food. Chem. 70, 10886-10898 (2022). HPTLC of 81 veterinary drugs from 6 different groups (glucocorticoids, anthelmintics, antiparasitics, coccidiostats, nonsteroidal anti-inflammatory drugs, and antibiotics) in 4 different matrices (honey, pig muscle, cow milk, and chicken eggs) on silica gel with acetonitrile - ammonia - ethanol 13:4:3 up to 80 mm and then in the reverse direction with methanol - acetonitrile - ethanol - ammonia 6:2:1:1 up to 45 mm. After each step, the plates were automatically dried in a cold stream of air for 3 min. Detection under UV light at 254 nm and fluorescence light detection (FLD) at 366 nm. Zones were eluted from the plate using a fully automated auto TLC-LC-MS interface for further analysis by high-resolution tandem mass spectrometry. Most veterinary drugs except penicillins and cephalosporins were detected at the 5 μg/kg level in pig muscle, cow milk, and chicken eggs and 25 μg/kg level in honey.

      Classification: 4d, 28a
      131 079
      Equivalency calculation of unknown enzyme inhibitors in situ the adsorbent of effect-directed autograms
      E. AZADNIYA, Gertrud MORLOCK* (*Institute of Nutritional Science, and Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany, Gertrud.Morlock@uni-giessen.de)

      Anal. Methods. 11, 4939-4945 (2019). HPTLC of Peganum harmala seeds on silica gel with ethyl acetate - methanol - ammonia (25%) 85:11:4. Detection under UV light at 254 and 366 nm. Track pattern application by applying each reference compound solution (physostigmine: 0.1–1.5 ng/zone; rivastigmine tartrate and piperine: 200–2000 ng/zone). A new piezoelectric spraying workflow was applied for the HPTLC-enzyme assay: the plate was sprayed with the enzyme solution (6.6 units per mL AChE or 3.3 units per mL BChE), followed by incubation at 37 °C for 25 min and spraying with 0.5 mL substrate-chromogenic solution and drying. The enzyme inhibition densitograms of both assays were measured by inverse scan at 546 nm using a mercury lamp. Equivalency of the AChE/BChE inhibition was calculated for two quantitative modes: applied and developed. A higher accuracy was obtained via an appropriate co-developed reference inhibitor for the enzyme inhibition equivalency calculation. 

      Classification: 4e, 20
      131 003
      Development of a high-performance thin-layer chromatography method for the quantification of alkyl glycerolipids and alkenyl glycerolipids from shark and chimera oils and tissues
      M. PAPIN, C. GUIMARAES, B. PIERRE-AUE, D. FONTAINE, J. PARDESSUS, H. COUTHON, G. FROMONT, K. MAHÉO, A. CHANTÔME, C. VANDIER*, M. PINAULT (*Nutrition, Growth and Cancer INSERM UMR 1069, University of Tours, Tours, France; christophe.vandier@univ-tours.fr)

      Marine Drugs 20(4), 270 (2022). Samples were ether glycerols (EG) purified: (A) from Chimaera monstrosa liver oil (Chimaeridae); (B) from mixed liver oil of sharks Centrophorus squamosus (Centrophoridae) and Somniosus microcephalus (Somniosidae); (C) from Macaca fascicularis hearts (Cercopithecidae); (D) from tumors obtained by grafting in mice the human melanoma cell line MDA-MB-435s, and (E) from periprostatic adipose tissue of men with prostate cancer. Reduction of (phospho)ester glycerolipids into EG and fatty alcohols was part of the purification process. Octadecyl-glycerol and octadecenyl-glycerol were used as standards of alkyl- and alkenyl-glycerols, respectively. HPTLC on silica gel previously developed with chloroform – methanol 1:1, air-dried and activated for 30 min at 110° C. Application under nitrogen stream (6 bar). Development with petroleum ether – diethyl ether – acetic acid 60:140:1. After 2 h drying at room temperature under ventilation hood, visualization by 50 s immersing into sulfuric acid (7 % in ethanol), followed by 2 h drying under air-stream, and 14 min heating at 140° C. Plates were documented under white light illumination and densitometry was performed by computered scanning of the pictures. Alkyl-glycerols (mean hRF 34, LOQ 1235 ng/band) and alkenyl-glycerols (mean hRF 44, LOQ 2352 ng/band), present in all samples (except alkenyl-glycerols in shark oil), were quantified after method validation for specificity, sensitivity, accuracy, precision and repeatability. Linearity range was 1000 ng – 7000 ng for both EG types. To confirm the band identification, samples and standards were also submitted to acidic hydrolysis before HPTLC application. In this case, the bands of alkenyl glycerols did not appear, because chlorhydric acid reacted with the vinyl ether bonds to form glycerol and aldehydes.

      Classification: 4d, 4e, 9, 11c, 32f
      130 037
      Quantitative thin layer chromatography for the determination of medroxyprogesterone acetate using a smartphone and open-source image analysis
      Mary E. SOWERS*, R. AMBROSE, E. BETHEA, C. HARMON, D. JENKINS** (* and ** FHI 360, Product Quality and Compliance, Durham, North Carolina, USA; *msowers@fhi360.org; ** djenkins@fhi360.org)

      J Chromatogr A, 1669, 462942 (2022). Samples were medroxyprogesterone acetate (MPA) as standards and commercial drug extracts, dissolved in dichloromethane. TLC on silica gel (preactivated by 30 min heating at 120 °C) with dichloromethane – ethyl acetate 10:1, followed by 30 min drying at 120 °C. Derivatization by spraying with sulfuric acid (50 % in ethanol). Visualization in a 3D-printed chamber designed especially for this purpose, blocking extraneous light and including a smartphone holder, a fluorescent lamp and an optical density step tablet. Pictures were taken with the smartphone digital camera, after spraying (6 background images) and after 10 min heating at 120 °C (6 foreground images). In the last case, MPA appeared as black spots (hRF 16–20). Using an image processing software program: (1) one averaged background image and one averaged foreground image were created by concatenation and were split into 3 colour channels; (2) the green colour channels were corrected to remove background noise, by subtraction of an averaged darkfield image (taken on blank plate without light) and by comparison ratio to an averaged blankfield image (taken on blank plate with light); (3) the pixel values of the MPA bands were converted to optical density values through the Robard’s function, by comparison to a reference image of a theoretical optical density step tablet; (4)  furthermore, the corrected background image was subtracted from the corrected (and denoised with a Gaussian Blur) foreground image; a triangle threshold algorithm was applied on the resulting image, and was converted to a mask (white spots on black background); (5) applying the binary mask to the original corrected images (obtained in (2)), the final integrated density values of MPA spots were obtained. This method was validated for linearity range (1.25–3.75 mg/mL), for precision, for reproducibility, for robustness, and for accuracy expressed as average recovery values (101 % overall mean) by comparison of TLC results with HPLC-DAD results.

      Classification: 3f, 13a, 32a
      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
      130 147
      Globotriaosylceramide-related biomarkers of Fabry disease identified in plasma by high-performance thin-layer chromatography – densitometry – mass spectrometry
      C. JARNE, L. MEMBRADO, M. SAVIRÓN, J. VELA, J. ORDUNA, R. GARRIGA, J. GALBÁN, V. L. CEBOLLA* (*Institute of Carbon Chemistry, Spanish National Research Council (CSIC), Saragossa, Spain; vcebolla@icb.csic.es)

      J Chromatogr A 1638, 461895 (2021). Samples were sphingolipid-rich fractions of unproteinated blood plasma from healthy humans or from Fabry’s disease patients, as well as standards of sphingomyelin (SM) and of globotriaosylceramides (Gb3 = ceramide trihexosides), and related compounds (lyso-ceramide trihexosides, lactosyl ceramide, glucosyl ceramide). HPTLC on silica gel (Lichrosphere with spherical particles) by automated multiple development with a 9-step gradient, starting with pure methanol and ending with dichloromethane – methanol 9:1. Visualization and densitometry under UV 190 nm. Derivatization for Gb3 and derivatives (but not for SM) by immersion into orcinol solution (0.2 %, with sulfuric acid 10 %), followed by 15 min heating at 100 °C and by densitometry under visible light 550 nm. Bands of interest were directly eluted with methanol from underivatized plates into an ion-trap MS, through the oval head of a TLC-MS interface (with stainless steel frit to remove silica gel particles). Two different ionization processes were used: (A) electrospray ionization (ESI, capillary voltage 4 kV, endplate offset voltage -0.5 kV, nebulizer pressure 40 psi, drying gas 9 mL/min at 350 °C); (B) atmospheric pressure chemical ionization (APCI, capillary voltage 2–3 kV, current intensity 4.5 µA, nebulizer pressure 45 psi, drying gas 5 mL/min at 350 °C; vaporization at 450 °C). Full MS spectra were recorded up to m/z 1500 in positive ion mode. The relative ion intensities were used to quantify the detected species. Previous to this study, the precision of the elution head positioning was tested on Gb3 standard zones, comparing 3 positions for analyte elution: from the centre and from each higher or lower side of the band. The same main m/z peaks were observed in the 3 positions, but in different proportions. This was explained by the presence of coeluting Gb3 subclasses (the ceramide moiety CM being either saturated, mono-unsaturated fatty acyl with a slightly higher migration distance, or polar hydroxyl fatty acyl with the opposite effect on migration) and of coeluting Gb3 isoforms (the hexoside moiety consisting of glucose and/or galactose units). This resulted in the broadening and partial splitting of the standard band. In the plasma samples, 19 molecular species of Gb3 were identified (depending on the CM, the sugar isoforms being undistinguishable by MS): 5 with a saturated CM, 7 with two additional double bonds on the CM, 7 with a methylated CM. In case of Fabry’s disease, most Gb3 species with saturated CM were highly increased, whereas other species were decreased.

      Classification: 4e, 11c, 11e, 32f
      130 146
      Development of a thin-layer chromatography bioautographic assay for neuraminidase inhibitors hyphenated with electrostatic field induced spray ionisation-mass spectrometry for identification of active Isatis indigotica root compounds
      Y. ZANG (Zang Yichao), Y. MIAO (Miao Yu), T. WU (Wu Tao)*, Z. CHENG (Cheng Zhihong)** (*Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China, laurawu2000@163.com; **Department of Natural Medicine, School of Pharmacy, Fudan University, Shanghai, China, chengzhh@fudan.edu.cn)

      J Chromatogr A 1638, 461597 (2021). Samples were Isatis tinctoria (= I. indigotica) root extracts (Brassicaceae) and their fractions. Standards were oseltamivir acid (OA), a neuraminidase (NA) inhibitor; pinoresinol (PR, a lignan), β-sitosterol (SS, a sterol), and dihydro-neoascorbigen (DHNA, an alkaloid). HPTLC / TLC on silica gel with (1) petroleum ether – ethyl acetate – acetic acid 48:8:1 for petroleum ether extracts and SS, or 30:40:1 for ethyl acetate extracts, or 10:30:1 for PR; (2) with toluene – ethyl acetate – methanol – formic acid 16:3:1:2 or 10:4:1:2 also for ethyl acetate extracts and DHNA; (3) with n-butanol – acetic acid – water 25:4:3 for butanol extracts. OA was applied but not developed. RP-18, polyamide, cellulose, alumina layers were tested, but the resolution was lower. Derivatization by spraying with sulfuric acid (10 % in ethanol). Enzymatic assay by immersion of the plates into neuraminidase solution (6 U/mL), followed by 1 h incubation at 37 °C and by immersion into chromogenic substrate solution (1.75 mM 5-bromo-4-chloro-3-indolyl-α-D-N-acetylneuraminic acid). After 5 min, NA inhibitors were seen as white zones on blue background. The experiment was previously improved for the following parameters: incubation times, substrate and enzyme concentrations, followed by statistical evaluation and calculations using Box-Behnken design. Quantification by absorbance measurement (detection wavelength 605 nm, reference wavelength 420 nm). In optimal conditions, OA had LOD 300 ng/zone. Zones of interest on underivatized plates were directly submitted to MS, using EFISI (electrostatic-field-induced spray ionisation), as follows. Chromatograms were immersed 1–3 s into dimethicone – n-hexane 1:1 to form a hydrophobic film, and dried 30 min at room temperature; on the analyte spot, a hydrophilic droplet was formed with 5 µL methanol – water 1:1, extracting the analyte from the layer; the analyte was further attracted through a capillary tube (3–4 cm long, made of non-deactivated fused silica) under a strong electrostatic field, into the in-let orifice of the triple-quadrupole ­– linear ion-trap MS (induction voltage 4 kV; capillary voltage 40 V; tube lens voltage 100 V; capillary temperature 200 °C). Full-scan spectra were recorded in m/z range 50 – 1000, helium was used for collision-induced dissociation. 11 active compounds were identified in the extract: SS, 6 alkaloids (including cycloanthranilylproline, DHNA, hydroxy-indirubin, isatindigodiphindoside, isatindinoline A and), 3 lignans (including PR and isolariciresinol), 1 fatty acid (trihydroxy-octadecenoic acid).

      Classification: 4e, 8a, 8b, 11a, 13c, 22
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