Concept: Thin layer chromatography
Reproducible fabrication of the hierarchically porous monolithic silica in a large volume exceeding 1000 mL has been established. By the hydrothermal enlargement of the fully accessible small pores to exceed 50 nm in diameter, the capillary force emerged on solvent evaporation was dramatically reduced, which allowed the preparation of crack-free monoliths with evaporative solvent removal under an ambient pressure. The local temperature inhomogeneity within a reaction vessel in a large volume was precisely controlled to cancel the heat evolved by the hydrolysis reaction of tetramethoxysilane and that consumed to melt ice cubes dispersed in the solution, resulting in large monolithic silica pieces with improved structural homogeneity. Homogeneity of the pore structure was confirmed, both on macro- and meso-scales, using scanning electron microscopy, mercury intrusion and nitrogen adsorption/desorption measurements. Furthermore, the deviations in chromatographic performance were examined by evaluating multiple smaller monolithic columns prepared from the monolithic silica pieces cut from different parts of a large monolith. All the daughter columns thus prepared exhibited comparable performances to each other to prove the overall homogeneity of the mother monolith. Preliminary results on high speed separation of peptides and proteins by the octadecylsilylated silica monolith of the above production have also been demonstrated.
The objective of the present work was to develop a plant-bacterial synergistic system for efficient treatment of the textile effluents. Decolorization of the dye Scarlet RR and a dye mixture was studied under in vitro conditions using Glandularia pulchella (Sweet) Tronc., Pseudomonas monteilii ANK and their consortium. Four reactors viz. soil, bacteria, plant and consortium were developed that were subjected for treatment of textile effluents and dye mixture. Under in vitro conditions G. pulchella and P. monteilii showed decolorization of the dye Scarlet RR (SRR) by 97 and 84%, within 72 and 96 h respectively, while their consortium showed 100% decolorization of the dye within 48 h. In case of dye mixture G. pulchella, P. monteilii and consortium-PG showed an ADMI removal of 78, 67 and 92% respectively within 96 h. During decolorization of SRR G. pulchella showed induction in the activities of enzymes lignin peroxidase and DCIP reductase while P. monteilii showed induction of laccase, DCIP reductase and tyrosinase, indicating their involvement in the dye metabolism. High Performance Liquid Chromatography (HPLC), Fourier Transform Infra Red Spectroscopy (FTIR) and High Performance Thin Layer Chromatography (HPTLC) confirmed the biotransformation of SRR and dye mixture into different metabolites. Soil, bacteria, plant and consortium reactors performed an ADMI removal of 42, 46, 62 and 93% in the first decolorization cycle while it showed an average ADMI removal of 21, 27, 59 and 93% in the next three (second, third and fourth) decolorization cycles respectively for the dye mixture within 24 h. Consortium reactor showed an average ADMI removal of 95% within 48 and 60 h for textile effluents A and B respectively for three decolorization cycles, while it showed an average TOC, COD and BOD removal of 74, 70 and 70%, 66, 72 and 67%, and 70, 70 and 66% for three decolorization cycles of the dye mixture (second, third and fourth decolorization cycles), effluent A and effluent B respectively. Degradation of the textile effluents and dye mixture into different metabolites by the consortium reactor was confirmed using HPLC and FTIR. Phytotoxicity studies revealed the non-toxic nature of the metabolites of degradation of dye mixture, effluents A and B by consortium reactor. The developed consortial reactor system performed efficient treatment of the dye mixture and textile effluents, and can be used for treating large amounts of textile effluents when implemented as a constructed wetland by proper engineering approach.
An efficient HPTLC method was developed, which required minimal sample preparation for quantitation of the main anthocyanes in pomace, animal feed as well as various foods. The best separation of 11 anthocyanes was achieved on HPTLC plates silica gel 60 F254 with a mixture of ethyl acetate-2-butanone-formic acid-water for anthocyanins and ethyl acetate-toluene-formic acid-water for anthocyanidins. Due to the high flexibility of the HPTLC method, both anthocyane groups could be developed in a combined 2-step method. The second development was only necessary if anthocyanidins were detected in the samples. This normal phase separation was found superior to the best separation achieved on RP-18 phases with a mixture of water-n-propanol-formic acid. Absorbance measurement was performed using the multi-wavelength scan at 505 (or 510), 520, 530 and 555nm. The correlation coefficients of the calibrations ranged between 0.9993 and 0.9999 for the 11 anthocyanes. LOQs were all ≤90ng/zone, most even ≤30ng/zone and for pn-3-glc and pg-3-glc even ≤7ng/zone. With regard to the analysis of mv-3-glc in grape seed/marc meal and supplemented animal feed samples, the mean repeatabilities were 1.4% (laboratory 1) and 1.8% (laboratory 2). The intermediate precisions within a laboratory over several months were ≤6.7%. The ruggedness of the method was ≤5.5%. The method was transferred to other sample types. Juice and wine samples, which were from the same plant source, showed a comparable anthocyanin pattern, whereas the pattern was characteristically different between plant sources. Unknown anthocyanin sample components were analyzed via HPTLC-ESI-MS by eluting the zones of interest with the TLC-MS Interface, which was helpful for further characterization of unknowns. An interesting tool was demonstrated by effect-directed analysis with regard to radical scavenging properties and general bioactivity based on detection with Vibrio fischeri bacteria.
SUMMARY The present study was designated to ascertain the anthelmintic activity of the rhizomes of Paris polyphylla and to isolate and characterize the active constituents. The methanol extract from rhizomes of P. polyphylla showed signiﬁcant anthelmintic activity against Dactylogyrus intermedius with the median effective concentration (EC50) 22·5 mg L-1. Based on this finding, the methanol extract was fractionated by silica gel column chromatography in a bioassay-guided fractionation yielding 2 bioactive compounds, the structures of these compounds were elucidated as formosanin C and polyphyllin VII. The in vivo tests revealed that formosanin C and polyphyllin VII were significantly effective against D. intermedius with EC50 values of 0·6 and 1·2 mg L-1, respectively. The acute toxicities (LC50) of formosanin C and polyphyllin VII for grass carp were 2·8 and 2·9 mg L-1, respectively. The overall results provide important information for the potential application of formosanin C and polyphyllin VII in the therapy of serious infection caused by D. intermedius.
A reversed phase chromatographic system, composed of a stationary phase of C silica gel (ODS, 20μm) and a mobile phase of ethanol/water, was used to separate liquiritin and liquiritigenin in the raw material of flavonoids. The linear adsorption isotherm and the equilibrium-dispersive model were adopted to approximatively describe the chromatographic separation behaviors of liquiritin and liquiritigenin in the raw material under different column temperatures, ethanol contents and flow rates of the mobile phase, sample concentrations and feeding times. Combined with orthogonal design, the ED model was used to optimize the chromatographic separating conditions, the corresponding experimental result with a good agreement was obtained and the overload separation was realized.
Coiled planar capillary chromatography columns (0.9 mm I.D. × 60 cm L) were 3D printed in stainless steel (316L), and titanium (Ti-6Al-4V) alloys (external dimensions of ∼5 × 30 × 58 mm), and either slurry packed with various sized reversed-phase octadecylsilica particles, or filled with an in situ prepared methacrylate based monolith. Coiled printed columns were coupled directly with 30 × 30 mm Peltier thermoelectric direct contact heater/cooler modules. Preliminary results show the potential of using such 3D printed columns in future portable chromatographic devices.
A new method for on-spot detection and characterization of organic compounds resolved on thin layer chromatography (TLC) plates has been proposed. This method combines TLC with dielectric barrier discharge ionization (DBDI), which produces stable low-temperature plasma. At first, the compounds were separated on TLC plates and then their mass spectra were directly obtained with no additional sample preparation. To obtain good quality spectra the center of a particular TLC spot was heated from the bottom to increase volatility of the compound. MS/MS analyses were also performed to additionally characterize all analytes. The detection limit of proposed method was estimated to be 100 ng/spot of compound.
In this study Monascus strains were screened for lovastatin production. These strains namely Monascus purpureus, Monascus sanguineus and their co-culture were able to produce lovastatin in solid state fermentation. Sensitivity of lovastatin was tested on Saccharomycess cerevaceae and Candida sp. where the former exhibited large zone of inhibition as compared to the latter. Presence of lovastatin was confirmed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Quantification of lovastatin was done with UV spectrometer at 238 nm. Further, Plackett-Burman methodology was applied for screening of nutrients for lovastatin production. Different substrates were screened and amongst them, wheat bran was found to be the best substrate for lovastatin synthesis. Seven nutrients were screened according to the Plackett-Burman design for lovastatin yield. MgSO4.7H2O showed the positive impact on lovastatin yield whereas lactose showed the maximum negative effect with M. purpureus. For M. sanguineus, CaCl2.2H2O displayed the dominant negative effect and soybean the significant positive. With co-culture, the effect of lactose was positive whereas that of malt extract was negative and dominant. The maximum lovastatin yield for M. sanguineus, M. purpureus and co-culture was estimated to be 0.402, 0.27 and 0.26 mg/g respectively.
An efficient and stability-indicating method has been developed and validated for the quantitative determination of tetrahydrofuran (THF), a hydrolytic degradation impurity, in Busulfan injectable pharmaceutical products by using gas chromatograph equipped with a liquid autosampler and a flame ionization detector. The chromatographic separation was performed on a fused silica capillary (Stabilwax; 60 m length × 0.32 mm i.d., 0.5 µm film thickness) column. The methodology was validated in accordance with regulatory guidelines. The proposed method was found to be specific, stable, precise, linear, accurate, robust, and rugged in the concentration range from 4 to 1,080 ppm for THF. The developed method was successfully applied to determine the THF content in Busulfan injectable pharmaceutical products.
40 isoeugenol-tolerant yeasts were isolated from the rhizosphere soil samples which in turn were collected from aromatic plants in different regions of Iran, and further tested for their ability to grow on a minimal medium containing isoeugenol as the sole carbon and energy source. Nine isolates which were able to grow on isoeugenol were examined for their ability to convert isoeugenol into vanillin under growing cell experiments. Of the tested yeasts, the highest conversion efficiency was observed in isolate MP24. The isolate was identified as Trichosporon asahii based on morphological, biochemical and molecular (ITS region) characters and tested to effectively convert isoeugenol into vanillin under resting cell system. A comparative analysis of thin layer chromatography (TLC), UV-Vis spectrometry, and high-performance liquid chromatography (HPLC) verified that vanillin and vanillic acid are accumulated as two major metabolites using T. asahii strain MP24 resting cells. In the presence of 7.5 g/l of wet weight cells of the strain MP24 pre-grown on isoeugenol and harvested at the end of the exponential growth phase, the optimal concentration of vanillin reached 2.4 g/l with a molar conversion of 52.5% in the potassium phosphate buffer (100 mM, pH 5.8) supplemented with 5 g/l of isoeugenol and 2% (v/v) N,N-dimethylformamide (DMF). The total concentration of vanillin and vanillic acid obtained from the bioconversion process was 4.2 g/l (total molar yield of 88.3%). Until now, no data has been published on the conversion of isoeugenol into vanillin by the strains of the genus Trichosporon.