Showing papers on "Thin-layer chromatography published in 2019"

Recent Trends in the Application of Chromatographic Techniques in the Analysis of Luteolin and Its Derivatives.

Abstract: Luteolin is a flavonoid often found in various medicinal plants that exhibits multiple biological effects such as antioxidant, anti-inflammatory and immunomodulatory activity. Commercially available medicinal plants and their preparations containing luteolin are often used in the treatment of hypertension, inflammatory diseases, and even cancer. However, to establish the quality of such preparations, appropriate analytical methods should be used. Therefore, the present paper provides the first comprehensive review of the current analytical methods that were developed and validated for the quantitative determination of luteolin and its C- and O-derivatives including orientin, isoorientin, luteolin 7-O-glucoside and others. It provides a systematic overview of chromatographic analytical techniques including thin layer chromatography (TLC), high performance thin layer chromatography (HPTLC), liquid chromatography (LC), high performance liquid chromatography (HPLC), gas chromatography (GC) and counter-current chromatography (CCC), as well as the conditions used in the determination of luteolin and its derivatives in plant material.

Thin-Layer Chromatography

Abstract: Thin-layer chromatography , Thin-layer chromatography , کتابخانه مرکزی دانشگاه علوم پزشکی تهران

Advances in chiral multidimensional liquid chromatography

Abstract: It is well known that the chiral separation is different but very important in separation science. Increase in number of chiral centers makes the chiral separations more difficult. In this respect multidimensional chromatography is gaining importance in chiral separations. There is a great demand of multidimensional chromatography in the chiral separations. The present article describes the separation and identification various racemates using multidimensional chromatography i.e. high performance liquid chromatography, gas chromatography, super critical fluid chromatography, thin layer chromatography. Besides, the efforts were made to discuss the importance of chiral separations, multidimensional chromatography, future perspectives and challenges. Certainly, this article will be useful for the researchers, academicians, government authorities and industrial persons.

Analytical methods for the determination of paracetamol, pseudoephedrine and brompheniramine in Comtrex tablets.

Abstract: Comtrex® tablets composed of paracetamol, pseudoephedrine and brompheniramine are widely used for relieving symptoms related to common cold. This study has overcome the challenging dosage form ratio (250:15:1) and proposed chromatographic methods for analyzing the ternary combination were utilized displaying different apparatus, solvents and sensitivity ranges. Three chromatographic methods namely thin layer chromatography (TLC), high performance liquid chromatography with ultra-violet detection (HPLC–UV) and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) were developed and validated for the simultaneous determination of the three drugs. Concerning the TLC method, aluminum TLC plates pre-coated with silica gel 60F254 were used and methanol:water:ammonia (9:1:0.1, v/v/v) was applied as a mobile phase; scanning of the plates was carried out at 254 nm. For the HPLC–UV method C18 column was used with an isocratic elution mobile phase composed of water:acetonitrile (75:25, v/v; pH 3.2) and the detection was at 210 nm. For the UPLC-MS/MS method; separation was performed on a UPLC-BEH C18 column with methanol: 0.1% ammonium formate (60:40, v/v) as the mobile phase utilizing diphenhydramine as an internal standard and mass spectrometry was used for detection. The methods were simple, sensitive, accurate and precise. Statistical analysis revealed no significant difference from the reported methods in regard to accuracy and precision.

Thin-layer chromatography in medicinal chemistry

Abstract: Among widely used chromatographic methods modern thin-layer chromatography is not only the simplest to perform but is also considered as respectable analytical method in various phases of drug disc...

Speciation of astatine reacted with oxidizing and reducing reagents by thin layer chromatography: formation of volatile astatine

Abstract: Radio-chromatography was conducted by using the astatine radionuclides 209,210,211At produced in the 7Li induced reaction of 209Bi. The speciation of dissolved astatine chemical species of astatide (At−), astatate (AtO3−) and perastatate (AtO4−) was carried out by thin layer chromatography on silica gel with an ethanol/water solution. Amounts of the astatine species varied with concentrations of oxidizing and reducing reagents, potassium periodate, sodium sulfate and hydrazine hydrate. The oxidation–reduction reactions between At−(−I) and AtO3− (V) were found to form volatile At0 (0) and release it from a silica gel thin layer in the development.

Phytochemical Profiling and Larval Control of Erythrina variegata Methanol Fraction against Malarial and Filarial Vector.

Abstract: Erythrina variegata (E. variegata) bioactive chemical has been the potential to be utilized as a good, eco-friendly approach for the control of mosquito population. In the present investigation, methanol extract using insecticidal compounds isolated against mosquito larvae kill assay was carried out. Secondary metabolism was characterized by thin layer chromatography, column chromatography, Fourier transform-infrared spectroscopy, gas chromatography-mass spectral, and identification of compound. Mosquito immature third instar larval, Anopheles stephensi, and Culex quinquefasciatus have been exposed to different concentrations of 50-250 µg/ml. Totally, larvae were death rate 98.2% (significant value ) from methanol extract and it is significant toxicity against larvae of An. stephensi and Cx. quinquefasciatus with LC50/LC99 values were 157.69/339.55 µg/ml and 137.67/297.33 µg/ml, respectively. FT-IR analysis in the functional groups such as alcohol, amines, amides, alkenes, amines, aromatic amines, aliphatic amines, , amines, and alkyl halides searched the identity of secondary metabolites, which may act as 12-Octadecenoic acid, methyl ester compound and clearly indicates being phytochemical. Chemical constituents of twenty-five compounds were identified in the methanol extract. The major components were 12-Octadecenoic acid and methyl ester (37.31%). Compound molecules consist of carbon 19 atoms (gray), hydrogen 36 atoms (greenish blue), and oxygen 2 atoms (red), indicated by the different colors. The results were obtained suggesting that, in addition to their pharmaceutical and medicine sources, 12-Octadecenoic acid, methyl ester compound can also serve as a natural mosquito control.

Determination of chlorogenic acid, polyphenols and antioxidants in green coffee by thin-layer chromatography, effect-directed analysis and dot blot – comparison to HPLC and spectrophotometry methods

Abstract: The great prevalence of thin-layer chromatography over high-performance liquid chromatography is connected with the possibility of analyzing many samples in parallel. Therefore, the method is often used in screening and/or effect directed analysis to compare composition and chemical/biological properties of many samples in one run. It was already proved, that high performance thin-layer chromatography, in many cases, can replace high-performance liquid chromatography for quantitative analysis. The main aim of the paper is to show that simple thin-layer chromatography can also be used as a quantitative or at least as a semi-quantitative method, even when it concerns effect directed analysis e.g. direct bioautography. Chlorogenic acid content was measured in four methanol extracts of various green coffees and in one extract of black coffee using thin-layer chromatography with ultraviolet detection and thin-layer chromatography with effect directed detection. High-performance liquid chromatography was used as a reference method. Additionally, total contents of polyphenols and antioxidants were estimated using thin-layer chromatography or dot-blot on chromatography plates. These results were compared to spectrophotometric methods. It was proved that thin-layer chromatography can be used as a quantitative (using densitometry) or semi-quantitative method (using other detection methods including effect directed detection) as well as for estimating total antioxidants or polyphenols content.

HPTLC Screening of Folic Acid in Food: In Situ Derivatization with Ozone-Induced Fluorescence

Abstract: This paper proposes a facile and specific method tailored for quantifying and confirming folic acid in food, based on the combination of high-performance thin layer chromatography with fluorescence densitometry and surface-enhanced Raman spectroscopy. Chromatography was carried out on silica gel plates, using methanol/ethyl acetate/ammonia (6:4:1, v/v/v) as the mobile phase. For the first time, ozone gas was utilized as the derivative agent, which efficiently induced the appearance of strong fluorescence of the analyte. Thereafter, fluorescent densitometry measurements were carried out for quantitative purpose, offering good linearity (R2 > 0.999) and sensitivity (0.7–1.4 mg/kg). In addition, the applicability and reliability of the established method was validated with food and food supplement samples, showing good agreement with the data obtained by conventional HPLC-UV as the benchmark, but with remarkably higher efficiency. Apart from that, the in situ-obtained surface-enhanced Raman spectroscopic fingerprint of bands under optimized conditions (532-nm incident laser and tenfold concentrated silver nanoparticles) enabled unambiguous identification of the targeted compound, serving as a convenient and affordable tool to prevent potential mistake from false-positive results.

Cytotoxic Effects of Compounds Isolated from Ricinodendron heudelotii.

Abstract: This study was designed to explore the in vitro anticancer effects of the bioactive compounds isolated from Ricinodendron heudelotii on selected cancer cell lines. The leaves of the plant were extracted with ethanol and partitioned in sequence with petroleum ether, ethyl acetate, and n-butanol. The ethyl acetate fraction was phytochemically studied using thin layer chromatography (TLC) and column chromatography (CC). Structural elucidation of pure compounds obtained from the ethyl acetate fraction was done using mass spectra, 1H-NMR, and 13C-NMR analysis. The isolated compounds were subsequently screened using five different cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7, SW-480, and normal lung epithelial cell line, BEAS-2B, to assess their cytotoxic effects. Nine compounds were isolated and structurally elucidated as gallic acid, gallic acid ethyl ester, corilagin, quercetin-3-O-rhamnoside, myricetin-3-O-rhamnoside, 1,4,6-tri-O-galloyl glucose, 3,4,6-tri-O-galloyl glucose, 1,2,6-tri-O-galloyl glucose, and 4,6-di-O-galloyl glucose. Corilagin exhibited the most cytotoxic activity with an IC50 value of 33.18 μg/mL against MCF-7 cells, which were comparable to cisplatin with an IC50 value of 27.43 µg/mL. The result suggests that corilagin isolated from R. heudelotii has the potential to be developed as an effective therapeutic agent against the growth of breast cancer cells.

Preparation and Characterization of Silica-Carrageenan Adsorbent for Pb2+ and Cd2+as Interfering Ion

Abstract: Pb2+ and Cd2+ are poisonous heavy metal ions produced by industrial waste. Waste processing is always required before such material is released into the environment. A safe biomaterial such as silica-carrageenan was designed for the heavy metal adsorbent. The objectives of this research were to prepare and characterize silica-carrageenan adsorbent as well as testing them in some applications, by thin layer chromatography as well as in batch methods. Adsorption profiles of the two heavy metal ions were expected. The result showed that this material contained 1.10 g/cm3 density, 2.10% moisture level, 81.70% ash level, and iodine adsorption value of 21.80%. SEM pictures showed the homogeneous structures with globular particle shape below 100 nm dimension. FT-IR spectra showed the presence of the siloxane groups (≡Si-O≡), silanols (≡Si-OH-), and -OH groups from carrageenan. Both ions could not be eluted by all of the organic eluents on TLC plates of the material, but less than 50% of Pb(II) can be separated. This adsorption value decreased in the presence of Cd(II) in the silica-carrageenan system in batch method.

Capillary electrophoresis, high-performance liquid chromatography, and thin-layer chromatography analyses of phenolic compounds from rapeseed plants and evaluation of their antioxidant activity.

Abstract: Rapeseed plants, known for oil production, are also known to contain phenolic compounds such as phenolic acids and flavonoids, with potential antioxidant and anticancer activities. The separation and identification of 11 phenolic acids in rapeseed extracts (including leaves, flowers, Chinese seeds, Belgian seeds, and cake) by capillary electrophoresis were investigated. The results were compared with those obtained with high-performance liquid chromatography and thin-layer chromatography and showed that the capillary electrophoresis technique offers several advantages for the identification of phenolic compounds in various rapeseed extracts. The antioxidant activity of rapeseed extracts and reference compounds was evaluated using four different approaches, namely, 2,2'-azinobis- (3-ethylbenzohiazoline-6-sulfonic acid assay, free radical 2,2-diphenyl-1-picrylhydrazyl assay, electron paramagnetic resonance spectroscopy and the measurement of the total polyphenol content. The contents of total polyphenols in the tested extracts were ranging between 5.4 and 21.1% m/m and ranked as follows: Chinese seeds ˃ Belgian seeds ˃ Flowers ˃ Cake ˃ Leaves.

Development of a simple, low-cost and rapid thin-layer chromatography method for the determination of individual volatile fatty acids

Abstract: In this paper, a new thin-layer chromatography (TLC) method for the determination of individual volatile fatty acids (VFAs) is presented. The experimental procedure is based on the derivatization of VFAs with activating agents and a naphthalene-based amine to form an amide derivative, followed by fast TLC separation of these VFA derivatives and visualization with phosphomolybdic acid at room temperature. Quantification is then performed by densitometric measurements using free software after taking TLC pictures in a home-made black box for homogeneous and reproducible lighting of the plates. Optimization of the experimental conditions enables fast determination (20 minutes for 3 samples) of VFAs with detection limits (1.5–2.5 mg L−1) and relative standard deviations (4.6–6.7%) satisfactory enough for our analytical purpose using low-cost instruments with easy to find materials and software. The protocol was then applied to real samples (aqueous extracts of sewage sludge composts) and the results were compared with gas chromatography analysis with good agreement between the two methods.

Application of planar and column micellar liquid chromatography to the prediction of physicochemical properties and biological activity of compounds

Abstract: A review of applications of micellar liquid chromatography (MLC) with special stress upon micellar thin layer chromatography (MTLC) in drug discovery is given. MLC and MTLC are presented as valuabl...

Qualitative and Quantitative Analysis of Capsaicin from Capsicum annum Grown in Jordan

Abstract: As there is an increasing demand for Capsaicin from pharmaceutical firms worldwide, the aim of the present study is to find a simple, fast, and reproducible method for its extraction from the fruit of capsicum annuum. Soxhlet extraction method using n-hexan as a solvent was used. Capsaicin was isolated and purified using a combination of column chromatography (CC), and thin-layer chromatography (TLC). High-Performance Liquid Chromatography (HPLC) was used for qualitative and quantitative analysis. Capsaicin was further identified by a spectroscopic method, including nuclear magnetic resonance (NMR) and Mass spectroscopy). The extraction yield was 11.5%, and Capsaicin concentrations in the extract was 8332.3 mg/kg with purity up to 73.95%, then purification of the extract was done by column chromatography, through using two solvent system until the purified Capsaicin detected and collected. Our results present a simple, fast, and reproducible method for the extraction of Capsaicin from the fruit of C. annuum with an almost high yield. The main advantage of the present method, in addition to its simplicity, it cut many steps that usually found in the literature.

Fast screening and quantitative mass spectral imaging of thin-layer chromatography plates with flowing atmospheric-pressure afterglow high-resolution mass spectrometry.

Abstract: Thin-layer chromatography (TLC) was interfaced to high-resolution mass spectrometry (MS) using a flowing atmospheric-pressure afterglow (FAPA) ambient desorption/ionization source. The influence of different TLC stationary phases on the mass spectral signal response and mass spectral image quality in FAPA-MS was carefully investigated. Specifically, a mixture of selected analgesics (acetaminophen), alkaloids (nicotine and caffeine), and steroids (cortisone) was deposited on different stationary phases (silica plates, RP-modified silica plates, CN-modified silica plates, DIOL-modified silica plates, and NH2-modified silica plates), and TLC plates with different thickness (100, 200, 250, 500, 1000, 2000 μm) of the stationary phase. After analyte separation, mass spectral imaging was performed of the complete TLC plate via FAPA-MS and the detected ion abundance was compared. It was found that TLC plates with larger particle sizes (10–12 μm) and thicker stationary phase layers (e.g., 1000 μm and 2000 μm) led to higher signals (protonated molecules) compared to smaller particles sizes (6–8 μm) and thinner stationary phases (e.g., 100 μm and 200 μm). Instrumental detection limits in the low ng-range/band were determined for TLC-FAPA-MS of caffeine from RP-modified TLC silica plates. Lastly, a quantitative TLC-FAPA-MS method using stable isotope dilution analysis was developed and applied to the quantification of caffeine in energy drinks.

Comparative extraction and simple isolation improvement techniques of active constituents' momilactone A and B from rice husks of Oryza sativa by HPLC analysis and column chromatography.

Abstract: This paper reports comparative extraction efficiencies and enhancement methods for natural herbicidal (growth inhibitors) compounds, momilactone A and B, respectively from the dried husks of Oryza sativa using different extraction techniques and different solvent systems. Four different extraction techniques viz. percolation, agitation with heat, sonication and soxhlet using five solvent systems as ethyl acetate, acetone, acetonitrile, methanol and methanol:water (8:2) were evaluated. In these studies, it was observed that maximum extract yield was obtained using in methanol and methanol/water mixture as extracting solvent by soxhlet technique although the content of total momilactones A and B was higher in the methanol/water mixture in comparison to other extractions. The successive and simple isolation enrichment technique for momilactones A and B were achieved by solid-matrix partitioning after the treatment of methanolic extract with charcoal and using ethyl acetate as extracting solvent for momilactones A and B. The quantitative analysis of the extraction and enrichment development protocol was validated by a simple, accurate, reproducible RP-HPLC-UV–VIS method using a binary gradient elution comprising of acetonitrile and water (70:30). The separation was achieved on a waters Spherisorb S10 ODS 2 column (250 × 4.6 mm, I.D., 10 µm) that achieved a greater degree of linearity within an overall concentration of extracts and momilactones A and B, 1 mg mL−1 and higher degree of correlation (0.9928 ≤ r2 ≤ 0.9936) for momilactones A and B. So far, comparative extraction of momilactones A and B and HPLC of these compounds has not been reported. Standards of momilactones A (1) and B (2) were isolated along with other two compounds as orizaterpenoid (3) and 7-ketostigmaterol (4) from ethyl acetate extract of rice hulls of O. sativa and checked purity by HPLC-PDA-MS and identification of these isolated compounds (1–4) by complete spectroscopic techniques as IR, 1H NMR, 13C NMR, 2D NMR and HR-MS. The qualitative analysis of momilactone A and B separation technique by thin layer chromatography was also developed.

Quantitative phytochemical screening, thin-layer chromatography analysis, high-performance thin-layer chromatography fingerprinting, and antioxidant activity of leaves of diospyros montana (roxb.)

Abstract: Objective: The objective of this study was to investigate important phytochemical constituents and antioxidant potential of Diospyros montana Roxb. leaves belonging to the family Ebenaceae. Methods: Leaves were exhaustively extracted with ethanol and fractionated into petroleum ether, chloroform, and ethyl acetate extracts. The various fractions were further analyzed for phytochemical composition and concentration-dependent antioxidant activity using conventional methods and high-performance thin-layer chromatography (HPTLC) fingerprinting. Since leaves contained phenolic compounds, extracts were evaluated for total phenolic content, flavonoids contents, and in-vitro antioxidant activity. Antioxidant potential was assessed using parameters such as superoxide radical scavenging, nitric oxide inhibition, and β-carotene/linoleic acid antioxidant activity. Results: Primitive phytochemical investigation highlighted the presence of steroids, saponins, flavonoids, alkaloids, and tannins which were confirmed by TLC and HPTLC fingerprinting. The antioxidant activity of leaf extracts decreased in the following order ethyl acetate > ethanolic > chloroform > petroleum ether and it was comparable with standards such as ascorbic acid and butylated hydroxytoluene. Conclusion: The present study concludes that the ethanolic extract and fractions of D. montana (Roxb.) leaves have prominent antioxidant activity comparable to standards. Therefore, D. montana (Roxb.) leaves may be used as a probable source of natural antioxidants in the pharmaceutical industry.

Antioxidant Activity of Daemonorops draco Resin

Abstract: Jernang resin is secretion of jernang rattan ( Daemonorops draco , Arecaceae family) fruits which is endemic in Southeast Asia. This resin has various biological activities and empirically used as wound healing, headache medicines, and fever remedies by Anak Dalam ethnic group from Jambi. This study was performed to evaluate the antioxidant activity of nonpolar fraction of D. draco resin which collected from Jambi Province, Sumatera, Indonesia. Resin was extracted with n-hexane, ethyl acetate, and methanol respectively. The antioxidant properties of the extracts were then evaluated using 1,1-diphenyl-2picryl-hidrazyl radical scavenging assay. The most active extract was further fractionated using n-hexane and methanol and separated using column chromatography and preparative thin layer chromatography. Separation of the extract was conducted through antioxidant assay-guided fractionation. Characterization of the active fraction was carried out by infrared spectroscopy. The result shows that ethyl acetate extract provides higher antioxidant activity (IC 50 = 27.61 µg/mL) compare to methanol and n-hexane extracts. N-hexane fraction of ethyl acetate extract used for further separation using column and preparative thin layer chromatography due to its antioxidant activity. Separation using column chromatography resulting in 9 fractions (F.1-9). Fraction F.5 provide high antioxidant activity (IC 50 = 17.27 µg/mL) and further separated using preparative thin layer chromatography resulting two fractions with lower antioxidant activity F.5.1 (IC 50 = 85.18 µg/mL) and F.5.2 (IC 50 = 34.94 µg/mL). Characterization of fraction F.5.2 using infrared spectroscopy showed that component in fraction F.5.2 contains NH-substituted benzene.

An approach to analysis of primary amines by a combination of thin-layer chromatography and matrix-assisted laser desorption ionization mass spectrometry in conjunction with post-chromatographic derivatization.

Abstract: On-spot derivatization has been suggested for the modification of primary amine containing compounds for their analysis by thin-layer chromatography hyphenated with matrix-assisted laser desorption ionization mass spectrometry. The proposed approach was based on post-chromatographic treatment of separated analytes inside the chromatographic zones on the thin-layer chromatography plates by tris(2,6-dimethoxyphenyl)methilium reagent. The derivatives, containing permanent positive charge, reveal exceptionally intense peaks of their cationic moieties and high signal/noise ratio in mass spectra recorded directly from the plates. The method was tested on a series of aliphatic, aromatic, and amine-containing pharmaceuticals.

TLC fingerprint with chemometrics and antioxidant activity of selected lichens

Abstract: Selected lichens, collected in forests near Lublin (Poland) were extracted using Soxhlet apparatus with dichloromethane and methanol as solvents. The obtained extracts were analyzed using the Thin Layer Chromatography with silica gel as adsorbent and the mixture of toluene, ethyl acetate and formic acid (10/10/0.5; v/v/v, respectively) as mobile phase. Developed chromatographic plates were sprayed using the Naturstoff reagent to confirm the presence of some phenolic compounds. The images of plates were digitalized using TLC Analyzer software and the obtained chromatograms were exported to Excel and converted to csv files. Next csv files were loaded to SpecAlign program, where the smoothing, subtraction (original word misspelled) of background and normalization were performed. The chemical differences between samples were confirmed using the similarity (Pearson correlation coefficient) and distance (Euclidean distance) indices with cluster analysis and Principal Component Analysis (PCA). Additional...

Thin-Layer Chromatographic Enantioresolution of (RS)-Ketorolac Using L-Amino Acids as Chiral Additive in Stationary Phase

Abstract: Direct resolution of enantiomers of (RS)-ketorolac was achieved by thin-layer chromatography on silica gel plates using enantiomerically pure L-tryptophan, L-valine, L-methionine, and L-histidine as chiral additive in the stationary phase. The solvent system (acetonitrile, methanol water, and chloroform) with different ratios was successful in resolving the enantiomers. Spots were detected by use of iodine vapor. The detection limit was 0.4 μg mL−1 for each enantiomer of (RS)-ketorolac. The native enantiomers were isolated and characterized.

New Method for Isolation of Naringin Compound from Citrus maxima

Abstract: This research aims to know the proper isolation method to isolate naringin compound from Citrus maxima for natural product chemistry laboratory. This natural product chemistry laboratory provides students with the essential skills and knowledge required to perform the extraction, isolation, and structural identification. The isolation began with sample preparation, extraction with methanol, partition with n-hexane, purification by crystallization using isopropanol, by analyzing the purity with Thin Layer Chromatography (TLC) tested, and the presence of functional groups with Fourier Transform Infrared (FT-IR) spectrophotometer test. The result of FT-IR spectrophotometer analysis contains hydroxy group (-OH), aromatic cyclic groups (C=C), CH2, CH3, and ether groups.

Systematic Separation and Purification of Alkaloids from Euchresta tubulosa Dunn. by Various Chromatographic Methods

Abstract: High-speed countercurrent chromatography (HSCCC) and silica gel column chromatography were used to separate and purify alkaloids from Chinese herbal medicine Euchresta tubulosa Dunn. The purpose of this study is to provide a system mode for rapid separation of alkaloids from natural products. In the experiment, the eluent of silica gel column chromatography was screened by thin layer chromatography (TLC) to obtain four components with different polarity. Then, the two-phase solvent systems of different components were selected and purified by HSCCC. Four alkaloids with relatively high content were obtained by this mode successfully, including matrine (28 mg), oxymatrine (32 mg), N-formyl cytisine (24 mg), and cytisine (58 mg). The purity was higher than 91% by high performance liquid chromatography–ultraviolet (HPLC-UV) and their chemical structures were identified by nuclear magnetic resonance (NMR) and electron ionization mass spectrometry (EI-MS). The results showed that the combination of HSCCC and silica gel column chromatography could make alkaloids from natural products separate systematically.

Stability indicating high-performance thin layer chromatography method for estimation of ascorbic acid in Hibiscus sabdariffa L. aqueous extract

Abstract: Background: High performance thin layer chromatography (HPTLC) has become a routine analysis technique due to its advantages of low operating cost, high sample throughput and need minimum sample clean up. Aim: To develop and validate an accurate, specific, repeatable and stability-indicating HPTLC method for the determination of ascorbic acid in presence of their degradation products for assessment of stability of the ascorbic acid in Hibiscus sabdariffa L. preparations. Methods: Chromatographic sample separations employed thin layer chromatography plates (20 cm x10 cm) pre-coated with silica gel 60 F254 as a stationary phase. Solvent system consisted of acetone: toluene: water: glacial acetic acid (26:4:4:1 v/v) while scanning wavelength of 269 nm was used. Ascorbic acid was subjected to stress degradation conditions i.e. oxidation, dry heat treatment, photo degradation and hydrolysis under different PH. Method was validated according to international council for harmonisation guidelines. Results: Peaks of products formed were well resolved with different Rf values. The linear regression data for the calibration plots showed good linear relationship with r2 = 0.9912 in the concentration range 2-4 µg/ml. The mean value slope and intercept were -531.72 and 8040.22 respectively. Conclusion: A rapid, simple, accurate and specific HPTLC method for determination of ascorbic acid in Hibiscus sabdariffa L. preparations was developed and validated. In addition, this method separated all the degradants from stress conditions showing that it is a stability indicating method. The developed method could now be used in quality control of H. sabdariffa herb products.

Reversed Phase High Performance Thin Layer Chromatography of Aqueous Samples in Student Laboratories Using the Example of Anthocyanin Patterns from Flower Petals

Abstract: When student projects require an analytical step that is robust and sufficiently selective, high performance thin layer chromatography (HPTLC) is a method to be considered. However, for student lab...